V O L U ME 6 , ISS U E 4 AP RI L 2 0 2 2 MASS M ONTHLY A PPL ICATIO N S IN STRE N G TH SPO R T E R I C H E LMS | G R E G N UCK O LS | MIC HAEL ZO URDO S | ERIC T REXL E R The Reviewers Eric Helms Eric Helms is a coach, athlete, author, and educator. He is a coach for drug-free strength and physique competitors at all levels as a part of team 3D Muscle Journey where he is also the Chief Science Officer. Eric regularly publishes peer-reviewed articles in exercise science and nutrition journals on physique and strength sport, in addition to contributing to the 3DMJ blog. He’s taught undergraduateand graduate-level nutrition and exercise science and speaks internationally at academic and commercial conferences. He has a B.S. in fitness and wellness, an M.S. in exercise science, a second Master’s in sports nutrition, a Ph.D. in strength and conditioning, and is a research fellow for the Sports Performance Research Institute New Zealand at Auckland University of Technology. Eric earned pro status as a natural bodybuilder with the PNBA in 2011 and competes in numerous strength sports. Greg Nuckols Greg Nuckols has over a decade of experience under the bar and a B.S. in exercise and sports science. Greg earned his M.A. in exercise and sport science from the University of North Carolina at Chapel Hill. He’s held three all-time world records in powerlifting in the 220lb and 242lb classes. He’s trained hundreds of athletes and regular folks, both online and in-person. He’s written for many of the major magazines and websites in the fitness industry, including Men’s Health, Men’s Fitness, Muscle & Fitness, Bodybuilding.com, T-Nation, and Schwarzenegger.com. Furthermore, he’s had the opportunity to work with and learn from numerous record holders, champion athletes, and collegiate and professional strength and conditioning coaches through his previous job as Chief Content Director for Juggernaut Training Systems and current full-time work on StrongerByScience.com. Michael C. Zourdos Michael (Mike) C. Zourdos, Ph.D., CSCS, has specializations in strength and conditioning and skeletal muscle physiology. He earned his Ph.D. in exercise physiology from The Florida State University (FSU) in 2012 under the guidance of Dr. Jeong-Su Kim. Prior to attending FSU, Mike received his B.S. in exercise science from Marietta College and M.S. in applied health physiology from Salisbury University. Mike served as the head powerlifting coach of FSU’s 2011 and 2012 state championship teams. He also competes as a powerlifter in the USAPL, and among his best competition lifts is a 230kg (507lbs) raw squat at a body weight of 76kg. Mike owns the company Training Revolution, LLC., where he has coached more than 100 lifters, including a USAPL open division national champion. Eric Trexler Eric Trexler is a pro natural bodybuilder and a sports nutrition researcher. Eric has a PhD in Human Movement Science from UNC Chapel Hill, and has published dozens of peer-reviewed research papers on various exercise and nutrition strategies for getting bigger, stronger, and leaner. In addition, Eric has several years of University-level teaching experience, and has been involved in coaching since 2009. Eric is the Director of Education at Stronger By Science. Table of Contents 6 BY GR EG NUCKOL S Can You Avoid Plateaus by Manipulating Relative Training Intensity? A recent six-month crossover study had subjects perform three months of low-load training and three months of moderate-load training, in a randomized order. The researchers found that lean mass gains were similar during the first and last three months of training, in contrast with other research. Read on to learn if you can truly avoid plateaus via wholesale shifts in relative training intensity every few months. 24 BY MI CHAEL C. ZOUR DOS Everything You Need to Know About Rest Intervals Over the past decade, longer rest intervals have prevailed over shorter rest intervals in both research and practice for hypertrophy and strength. However, most of the rest interval data are from male lifters. Thus, a rest interval study in female lifters is a welcome addition to the literature. 39 BY ER I C HEL MS Can Bodybuilders Change Their Intra-to-Extracellular Water Ratio During Peak Week? More research is steadily published examining the “peak week” methods bodybuilders use in attempts to acutely enhance stage appearance. This study assesses a potential mechanism behind many peaking methods: manipulating one’s intra-to-extracellular water ratio. 50 BY ER I C T R EXL ER Coaching Beyond the Spreadsheet: How (and Why) To Promote Intrinsic Motivation A lot of evidence-based coaches and fitness enthusiasts invest considerable time and effort into optimizing the nuts and bolts of their programs. A new meta-analysis on psychological aspects of coaching suggests that there are ample opportunities (beyond the spreadsheet) to enhance a lifter’s long-term success and well-being. 63 BY GR EG NUCKOL S “Activation Training” May Increase Glute EMG A new study suggests that you can increase your glute activation during squats by doing some light glute “activation training” twice per day. This article will discuss some potential confounders in the study, and how confident we can be that glute activation training will actually improve muscle growth and strength gains. 72 BY ER I C T R EXL ER Should You Adjust Training Volume While Cutting? How should you manipulate training volume while cutting? Due to a lack of direct research, it’s one of the most commonly debated questions in evidence-based fitness. A new systematic review adds fuel to the fire, but clarity still eludes us. 88 BY MI CHAEL C. ZOUR DOS Should You Take A Few Days Off to Peak Strength? I’ve previously contended that tapering is overrated. However, I haven’t touched much on training cessation as a tapering strategy. Is training cessation the tapering strategy that you need to peak strength? A new study examined this concept. 101 BY ER I C T R EXL ER Research Briefs In the Research Briefs section, Eric Trexler shares quick summaries of recent studies. Briefs are short and sweet, skimmable, and focused on the need-to-know information from each study. 123 BY MI CHAEL C. ZOUR DOS VIDEO: Time-Efficient Programming Strategies Part 2 Part 1 of our time efficiency series provided examples of training strategies which can be used to decrease training time. However, there are certain circumstances which warrant training twice per day, in which further adjustments are needed to accommodate two-a-days. Therefore, part 2 of this series provides practical examples for how time-efficient programming strategies can be used to make twoa-days feasible. 125 BY ER I C HEL MS VIDEO: Interpreting Failure and Non-Failure Data You might have noticed the studies comparing failure versus non-failure for hypertrophy outcomes often conflict. We’ve reviewed many of them in MASS, and not only do they tend to conflict with one-another, but even within the MASS team, we don’t always see eye-to-eye when interpreting the impact of failure. Why is that? In this video, you’ll understand why interpreting these data is challenging. Letter From the Reviewers V olume 6, Issue 4 of MASS has arrived, and it’s absolutely packed with content to help you take your training, nutrition, and coaching to the next level. On the training side, Greg’s got an excellent article related to programming and periodization, which specifically examines whether or not you can avoid plateaus by switching up your relative training intensity. This month had so many great papers to choose from that Greg opted to write a second full-length review in lieu of his Research Briefs; in his second article, Greg explores the concept of using “activation exercises” to promote more glute activation while squatting. Also in the Training Department, Dr. Zourdos has two fantastic articles this month. In the first, he covers a new paper exploring the psychological, physiological, and performance changes that accompany short-term cessation of training. In the second, he takes a deep dive into the literature on optimal interset rest periods for promoting resistance training adaptations. On the nutrition side, Dr. Helms covers a very interesting paper about “peak week” in physique athletes, with results that appear to challenge some of the conventional wisdom about attempts to manipulate intracellular and extracellular fluid balance. Dr. Trexler also covers a topic near and dear to more physique-oriented lifters this month, with an article that explores if (and how) lifters should be adjusting their lifting volume in order to maximize lean mass retention when they’re in a caloric deficit. Moving beyond the nutrition category, Dr. Trexler’s second article more broadly relates to psychology and coaching. It covers a paper about how autonomy-supporting coaching behaviors can maximize client success, while discussing a variety of ways you can use selfdetermination theory to support success for yourself or your clients. Finally, Dr. Trexler’s Research Briefs take a quick and concise look at the 5:2 diet (a form of intermittent fasting) in lifters, the use of continuous glucose monitors, the effects of morning versus evening workouts on energy expenditure, and some of the potential risks faced by female physique athletes. As for this month’s video content, Dr. Helms has a very insightful video about how to interpret studies comparing “failure” and “non-failure” training interventions. In addition, Dr. Zourdos is back with part 2 of his excellent (and very practical) video series on implementing time-efficient programming strategies. As always, we hope you enjoy this issue of MASS. If you have any questions about the articles or videos in this month’s issue, or you’d just like to discuss them further, be sure to post your questions or comments in the MASS Facebook group. Sincerely, The MASS Team Eric Helms, Greg Nuckols, Mike Zourdos, and Eric Trexler 5 Study Reviewed: Different Load Intensity Transition Schemes to Avoid Plateau and NoResponse in Lean Body Mass Gain in Postmenopausal Women. Carneiro et al. (2022) Can You Avoid Plateaus by Manipulating Relative Training Intensity? BY GREG NUCKOLS A recent six-month crossover study had subjects perform three months of low-load training and three months of moderate-load training, in a randomized order. The researchers found that lean mass gains were similar during the first and last three months of training, in contrast with other research. Read on to learn if you can truly avoid plateaus via wholesale shifts in relative training intensity every few months. 6 KEY POINTS 1. Healthy, postmenopausal women completed 24 weeks of lower-body resistance training, consisting of 12 weeks of moderate-load training (sets of 8-12 reps), and 12 weeks of low-load training (sets of 27-31 reps), performed in a randomized order. 2. Both orders of training sequencing produced similar increases in lean soft tissue mass (15). Furthermore, average rates of lean mass accrual were similar in the first and second 12 weeks of training. 3. The present study employed a crossover design and reported individual subject data. Such data allows us to probe questions related to optimizing relative training intensity for individuals, and the reliability of classifying people as “high responders” and “low responders” to resistance training. W hen you reach a plateau in your training – you keep training hard, but further muscle growth and strength gains are hard to come by – how can you break through that plateau? Potential options range from fun (dreamer bulk, baby), to practical-but-boring (try to sleep more and manage stress better), to illegal-in-many-jurisdictions (up the dose, lift the most). One surprisingly controversial option, however, is to make significant adjustments to your training program. Some will argue that changing your training program is only logical, since your current program isn’t producing the results you want. Other people will accuse you of “program hopping,” or say you have “training ADHD,” and that you just need to commit harder to your current training approach (especially if it previously produced solid results for you). So, what does the research say? Can you get the gains rolling again by changing your training approach, or is doing so a waste of time? Surprisingly, there’s not a ton of research on the topic. However, a recent study (1) purports to demonstrate that switching to a completely different relative training intensity (percentage of 1RM) can help you avoid a plateau. In the present study, subjects completed 24 weeks of training. Half of the subjects did 12 weeks of low-load training (starting with 30% of 1RM, and performing sets of 27-31 reps), followed by 12 weeks of moderate-load training (starting with 80% of 1RM, and performing sets of 8-12 reps). The other half did 12 weeks of moderate-load training first, followed by 12 weeks of lowload training. The researchers found that, in contrast with other research (which suggests that hypertrophy slows down dramatically after about three months of training), lean mass gains occurred at the same rate during both 12-week blocks of training. So, are wholesale changes in training intensity the holy grail for avoiding or breaking through plateaus? Read on to find out. I’m not fully convinced, but the design and thorough data reporting in the present study allow us to probe several interesting and practical questions related to individual responses to different training styles. 7 Purpose and Hypotheses Purpose The primary purpose of this study was to compare the effects of low-load training followed by moderate-load training, versus moderate-load training followed by low-load training, for the purpose of supporting lean mass accretion. The secondary purpose was to see how changing training intensity would affect responsiveness to resistance training. Hypotheses No hypotheses were directly stated. Subjects and Methods Subjects 24 postmenopausal women participated in the present study. All subjects were at least 50 years old, had not menstruated in the preceding 12 months, did not use hormone re- placement therapy, were free of significant cardiometabolic or orthopedic issues, and had not participated in regular physical activity more than once per week in the six months preceding the study. Subject characteristics can be seen in Table 1. Experimental Design This study took place over 28 weeks, including a 24-week training intervention. During the first week, subjects performed three familiarization sessions to get acquainted with the exercises used in the study (leg press, knee extensions, leg curls, and calf raises). During the second week, subjects completed 1RM tests to determine their initial training loads, and researchers collected the subjects’ basic anthropometric data (height, weight, and body fat), along with assessing thigh lean soft tissue mass (via DXA). From weeks 3-14, subjects completed twelve weeks of resistance training. During week 15, research- 8 ers reassessed the subjects’ thigh lean soft tissue mass and 1RM strength for all four training exercises. From weeks 16-27, subjects completed 12 more weeks of resistance training. Finally, thigh lean soft tissue mass was reassessed in week 28. Post-training 1RM strength was not assessed (or, at minimum, it wasn’t reported). All subjects completed two different resistance training programs. Both programs consisted of leg press, knee extensions, leg curls, and calf raises, all performed for three sets (2) with 90 seconds of rest between sets. All sets were performed “until, or close to, voluntary concentric failure,” according to the study (though, as far as I can tell, proximity to failure wasn’t strictly controlled or directly quantified). The two programs only differed in terms of training load. The moderate-load program started with subjects at 80% of their 1RM, with the aim of completing 8-12 reps per set, while the low-load program started with subjects at 30% of 1RM, with the aim of completing 27-31 reps per set. When subjects completed at least 12 reps during the first set of an exercise on the moderate-load program, or 31 reps during the first set of an exercise on the low-load program, training loads were increased by 5-10% for their next training session. Half of the subjects were randomly assigned to complete the moderate-load program first, while the other half completed the low-load program first. After the first 12 weeks of training and the mid-study strength and lean mass assessments, subjects switched training programs for the second half of the study. So, half of the subjects completed 12 weeks of moderate-load training followed by 12 weeks of low-load training, and half of the subjects completed 12 weeks of lowload training followed by 12 weeks of moderate-load training. The researchers were primarily interested in two outcomes: progression of training loads (absolute training loads, total reps completed, and volume load), and accrual of thigh lean soft tissue mass. The lean mass data was also analyzed in two different ways. First, the researchers compared the two training approaches (low-load followed by moderate-load training, versus moderate-load followed by low-load training) to see if either loading scheme produced better outcomes. Second, the researchers split apart “high responders” and “low responders” to resistance training following the first 12 weeks of training, using a median split (i.e., the 50% of subjects with the largest lean mass gains during the first 12 weeks of training were deemed to be high responders, and the 50% of subjects with the smallest lean mass gains were deemed to be low responders). They were interested in assessing whether training responsiveness during the first 12 weeks of training was predictive of responsiveness during the last 12 weeks of training, and whether changing relative training intensities would improve overall training responsiveness in the initial low responders. Findings Table 2 shows the training load progression observed following the two training approaches. Overall, both of the programs worked, insofar as absolute load and volume load in- 9 creased over time. I’m not too interested in the direct comparisons between the two programs, though. According to the results table, the low-load program looks like it was more effective, but I think that’s an artifact of the way initial training loads were assigned. Once people get a bit of training experience (i.e., once someone establishes decent strength endurance), they can generally complete considerably more than 27-31 reps at 30% of 1RM, whereas 8-12 reps at 80% of 1RM is pretty challenging for most folks. So, by using 30% of 1RM as the initial intensity for the low-load training protocol, I think the researchers simply (inadvertently) stacked the deck for low-load training to appear to allow for greater progression of training loads. Regardless, it’s clear that both programs effectively promoted improvements in strength (demonstrated by absolute training loads increasing in both programs) and work capacity (demonstrated by total volume load increasing in both programs). 10 Table 3 shows the changes in lean mass over time. Both protocols were similarly effective at promoting increases in thigh lean soft tissue mass. In the group completing low-load training followed by moderate-load training, subjects gained an average of 0.4kg of lean mass in the first 12 weeks of training, and 0.3kg of lean mass in the last 12 weeks of training, for a net increase of 0.7kg. In the group completing moderate-load training followed by low-load training, subjects gained an average of 0.3kg of lean mass in the first 12 weeks of training, and 0.4kg of lean mass in the last 12 weeks of training, also for a net increase of 0.7kg. However, an interesting pattern emerges when we look at the thigh lean soft tissue mass accrual of “low responders” versus the “high responders.” During the first 12 weeks of training, which were used to determine re- sponsiveness, the low responders gained very little thigh lean soft tissue mass (0.1kg), while the high responders gained 0.6kg. However, during the last 12 weeks of training, the low responders actually gained (nominally) more thigh lean soft tissue mass (0.4kg) than the high responders (0.2kg; p = 0.16). The high responders did still wind up gaining significantly more thigh lean soft tissue mass over the entire 24 weeks of training (0.8kg versus 0.5kg; p = 0.044), but the difference between high and low responders narrowed considerably. You can see individual subject data illustrating the different time course of lean mass gains in Figure 1. Criticisms and Statistical Musings My only significant criticism of the present study was the decision to analyze high versus 11 low responsiveness to training using a median split. Ultimately, if you’re interested in analyzing whether training responses during the first 12 weeks of training are predictive of training responses during the last 12 weeks of training, regression analysis is far more informative (3). With a median split, you flatten out differences between individuals, such that the worst responder is treated the same as a subject in the 49th percentile, and the best responder is treated the same as a subject in the 51st percentile. Similarly, subjects near the median who experienced very similar responses during the first 12 weeks of training are treated as if they’re completely different. I extracted the data in Figure 1 using WebPlotDigitizer, and wanted to see the relationship between relative increases in thigh lean soft tissue mass in the first 12 weeks, versus increases in the last 12 weeks of training. You can see the results in Figure 2. Each data point represents a single subject; their x-axis coordinate tells you their relative increases in thigh 12 lean soft tissue mass during the first 12 weeks of training, and their y-axis coordinate tells you their relative increase in thigh lean soft tissue mass during the last 12 weeks of training. As you can see, there wasn’t much of a relationship between hypertrophy during the first phase of training and hypertrophy during the second phase of training (r = -0.28; p = 0.18). This scatterplot is more informative than the group-level analysis comparing mean responses at the bottom of Table 3. And, while Figure 1 displays all of the same information seen in this scatterplot, it’s still harder to directly interpret since the low responders and high responders are split out onto different axes. However, when we treat training responsiveness as a continuous variable (rather than a binary variable), we can more clearly see that lean mass accretion during the first phase of training was poorly predictive of lean mass accretion during the second phase of training. Interpretation This is a study I’ve wanted to see for a long time. My anecdotal observation is that some people simply seem to respond better to heavier training, and some people simply seem to respond better to lighter training. However, the controlled evidence to back up that observation was shaky at best. There were two studies that could be used to make that case, but both of them had some obvious issues. First, a study by Beaven and colleagues ran subjects through four different training protocols (3 sets of 5 reps at 85% of 1RM, 4 sets of 10 reps at 70% of 1RM, 5 sets of 15 reps at 55% of 1RM, and 4 sets of 5 13 reps at 40% of 1RM), and tested the subjects’ acute salivary testosterone and cortisol responses (4). Subjects completed three weeks of training with the protocol that elicited the largest increase in testosterone:cortisol ratio, and three weeks with the protocol that elicited the smallest increase (or largest decrease) in testosterone:cortisol ratio. The researchers found that subjects experienced a larger increase in body mass during the three weeks when they performed the protocol that elicited the largest increase in testosterone:cortisol ratio. However, the limitations in that study should be obvious. The training intervention was really short (just three weeks with each protocol), and it’s a stretch to assume that increases in body mass necessarily equal increases in muscle mass. Another study by Jones and colleagues assigned subjects to training protocols that were supposed to be compatible with their genetics or incompatible with their genetics, using a proprietary algorithm (5). The subjects completed strength endurance-based training or power-based training. Overall, subjects experienced larger improvements in several measures of performance when training in a manner that was compatible with their genetics. However, that study contained a clear conflict of interest – the algorithm used to assign subjects to different groups isn’t publicly available, and an employee of the company that developed the algorithm was one of the authors of the study. Now, studies with conflicts of interest shouldn’t be discounted out of hand, but it helps for results to be independently validated by other research groups that lack those same conflicts of interest. To the best of my 14 knowledge, the results of the study by Jones and colleagues haven’t been replicated. Furthermore, as we’ve covered in MASS before, there’s quite a bit of evidence that many training variables have a much smaller influence on hypertrophy than innate differences in trainability. For example, a study by Hammarström and colleagues (reviewed in MASS; 6) investigated the effects of training volume (total sets performed) on quad growth. Subjects completed six weekly sets of quad work with one leg, and 18 weekly sets with another leg. The researchers found that higher training volumes tended to result in more muscle growth, but that innate differences in trainability influenced hypertrophy far more than training volume. In other words, someone who experiences a lot of muscle growth with high training volumes will probably experience a lot of muscle growth with lower training volumes, and someone who doesn’t experience much growth with low training volumes probably won’t experience that much more growth with higher training volumes. A study by Damas and colleagues (7 – also reviewed in MASS) had similar findings when testing the effect of keeping training variables consistent session-to-session versus varying load, rest intervals, the muscle actions performed, and training volume. Subjects who experienced a lot of growth following varied training were also likely to experience a lot of growth with more consistent training, and subjects who experienced little growth with varied training were unlikely to experience way more or way less growth with consistent training (Figure 3). Thus far, I’ve painted a pretty bleak picture for folks who want to optimize their training. Maybe manipulating training variables can improve your results slightly, but the vast majority of your results are merely dictated by your innate trainability. However, there’s a notable exception to this rule. Another study by Damas and colleagues tested the effects of different training frequencies (frequencies of 2, 3, and 5 times per week), using a within-subject unilateral design (8). Each training session employed the same volume, such that a frequency of five times per week coincided with 2.5-times more volume than a frequency of 2 times per week. In that study, innate trainability didn’t seem to matter quite as much. Some subjects grew a ton with higher volumes and frequencies (and not very much with lower volumes and frequencies), and some grew a ton with lower volumes and frequencies (and not very much with higher volumes and frequencies). So, while volume itself seems to matter less than innate trainability when training frequencies are the same (6), a single individual can achieve dramatically different results – either better results or worse results – when pairing higher or lower training volumes with higher or lower training frequencies (Figure 4). I’ve long suspected that relative training intensity was another variable that can influence individual results. Some people really seem to respond well to heavier training, while other people swear by low-load, highrep training. However, while some studies employing within-subject unilateral designs have tested the effects of different relative training intensities (9 – MASS review; 10 15 – MASS review), they haven’t reported individual subject data, which would be necessary to see if individual results do, in fact, significantly differ when training at different relative intensities. ilarly effective when it came before moderate-load training and when it followed moderate-load training (and the same was true with moderate-load training, preceding or following a period of low-load training). The present study helps fill that gap (1). While it didn’t employ a within-subject unilateral design, the subjects did all complete a relatively long period of both low-load training and moderate-load training. It’s possible that the crossover design may have introduced some sequencing effects (i.e., perhaps subjects respond differently to one training style after a period of training with a different training style), but that seems unlikely, since group-level results of both moderate-load and low-load training seemed unaffected by which training style was performed first. In other words, low-load training seemed sim- Referring back to Figure 2, it doesn’t just show individual results during the first twelve weeks of training versus the last twelve weeks of training. Since subjects changed training styles at the midpoint of the study, it also shows individual results following moderate-load training versus low-load training. Figure 5 displays the same data in a slightly different format (similar to Figure 1), showing that individual hypertrophy responses to one loading scheme have virtually no bearing on individual hypertrophy responses to the other loading scheme. 16 This is an exciting finding, because it presents us with another clear option to try when “normal” training isn’t producing particularly notable results in a particular trainee. Most hypertrophy-focused training employs a moderate set volume (5-10 sets per muscle group per session), a moderate intensity (loads that let you complete 6-15 reps per set), and a low-to-moderate frequency (training most muscle groups 1-3 times per week). For most people, that produces pretty good results. However, if that doesn’t work particularly well for someone, there aren’t a ton of great troubleshooting recommendations that we know are likely to produce substantially different outcomes. There are some things that might, on average, produce slightly better results (i.e., increasing training volume; 6). There are also plenty of options for which within-subject variability is unquantified. For example, we know that training to failure and stopping a few reps shy of failure tend to produce similar muscle growth, on average, but we don’t know if they tend to produce substantially different results within a single trainee. If stopping a few reps shy of failure doesn’t result in much growth for you, are you likely to achieve meaningfully different results if you start training to failure? We don’t know for sure. Ideally, we’d have a long list of training variables that are known to result in large within-individual differences in muscle growth. However, until now, the Damas study which tested the effects of different volumes and frequencies provided us with the only known set of variables that produce large within-subject differences in muscle growth (8). So, if “normal” hypertrophy training wasn’t working, you could advise someone to double (or halve) their weekly training volume and per-muscle training frequency, and be reasonably confident that such a recommendation would produce substantially different results…but that’s a pretty dramatic recommendation. The present study suggests that a less dramatic recommendation could also be prudent: if sets of 10 aren’t cutting it for you, give sets of 30 a shot instead. Before wrapping up, I want to tie up a few loose ends. First, the authors of the present study suggest that their findings demonstrate that shifting from moderate- to low-intensity training or from low- to moderate-intensity training prevents (or at least delays) plateaus, and preserves training responsiveness over a longer period of time (1). Some evidence suggests that hypertrophy tends to slow down quite a bit after about 12 weeks of training (11), but subjects in the present study grew just as much during the last 12 weeks of training as the first 12 weeks of training. However, I’m not sure I agree with the authors’ interpretation of their results. It appears to me that changing training intensities only preserved the same average rate of progress because it dramatically improved the results of the subjects who experienced minimal muscle growth during the first 12 weeks of training. If anything, changing training intensities may have hindered the growth of subjects who experienced substantial muscle growth during the first 12 weeks of training. In other words, average results were similar during both 12week blocks of training because most of the subjects completed one block of training they responded well to, and one block of training 17 they didn’t respond well to; for about half of the subjects, the first block of training was the effective block, and for the other half of the subjects, the second block of training was the effective block. I think a better takeaway is that you shouldn’t necessarily change training intensity every so often for its own sake; rather, you should change training intensity if it becomes clear that a particular relative training intensity isn’t producing the results you want, but you should stick with a particular relative training intensity as long as it’s still working for you. Second, this study could be interpreted as a study comparing linear periodization versus reverse linear periodization. As we discussed recently, it appears that linear and reverse linear periodization result in similar muscle growth, on average (12). The present study adds to that body of literature. Third, the present study beautifully illustrates a pitfall that’s pretty common in the evidence-based fitness community. When you consume a lot of scientific literature, it’s easy to fixate on average results, because most statistical techniques are focused on testing for differences between means. However, averages often cover up a lot of underlying variability. For example, imagine someone asks you, “should I give low-load training a shot? I’ve been doing sets of 8-12 for the past six months, and I haven’t seen any results.” It might be tempting to answer, “don’t waste your time. Low-load and moderate-load training produce similar muscle growth, so if moderate-load training isn’t working for you, low-load training probably won’t either.” While that answer would be based on a kernel of truth (13), it would still be a pretty bad answer. “Thing A and Thing B produce similar results, on average,” is not the same as, “Thing A and Thing B produce similar results for all (or even most) individuals.” When fielding questions or evaluating anecdotes, it’s important to keep that distinction in mind. Fourth, the present study helps illustrate one of my problems with the concept of identifying high versus low responders to resistance training. Ultimately, if someone is identified as a “high responder,” that just means they responded particularly well to one particular training program. Similarly, if someone is identified as a “low responder,” that just means they responded particularly poorly to a particular training program. Over the course of your training career, I’m sure you can think of periods where you were making rapid progress, and periods when your results were stagnating (or even regressing). If a researcher took a snapshot of your training at various points in your lifting career, they might identify you as a high responder sometimes, and a low responder other times. Thus, the label doesn’t seem particularly meaningful, because your innate ability to respond to training didn’t change – you were the same biological organism the whole time (I assume). In the present study, if the median split technique to identify high versus low responders was repeated after the subjects completed all 24 weeks of training, a full third of the subjects would have switched groups (Table 4). Four of the “high responders” (within the top 50% of responders) after 12 weeks of training would have been categorized as “low 18 responders” (within the bottom 50% of responders) after 24 weeks of training; similarly, four of the low responders after 12 weeks of training would have been categorized as high responders after 24 weeks of training. After completing a single training program, we really don’t know if a particular individual is a high or low responder to training in a general sense. Furthermore, it’s worth noting that virtually all subjects ended up accruing a substantial amount of lean mass over the course of the study. It’s not uncommon for studies to report that approximately 1/3rd of subjects are “nonresponders” – people who either lose muscle, or experience gains that fall below the limits of reliable detectability. In the present study, 7 out of 24 subjects (29%) either had reductions in lean mass, or increases smaller than 1.3% (the lower end of reliable detectability for the DXA used for lean mass measurements) after the first 12 weeks of training. However, after giving low responders the opportunity to try a new training program for an additional 12 weeks, only two subjects (8%) would have been classified as nonresponders after all 24 weeks of training. With all of that in mind, I think most classifications of “high responders,” “low responders,” and “nonresponders” are essentially bunk. At minimum, there’s not great evidence that such a classification is particularly persistent or reliable, and the present study provides evidence that such classifications are not persistent or reliable. Finally, just to address a potential criticism of this article, I’m sure some readers may be concerned that the subjects of the present 19 study were untrained postmenopausal women. First, I don’t think that’s inherently a limitation; postmenopausal women do exist, after all, and some of them read MASS. So, even if the results of this study don’t generalize beyond that population, the results are certainly still valuable. Second, and more importantly, I do suspect that the results of the present study will generalize to other populations. In studies on older adults, I’m primarily concerned about three things when assessing whether the results are likely to generalize: 1) are the subjects healthy enough to handle a robust training stimulus, 2) are the results broadly in line with studies on other populations, and 3) are the subjects so old that they simply don’t experience a robust training response anymore. This study ticks all three boxes. First, the subjects were completing 18 sets of quad training to failure (or near failure) per week, so they were clearly capable of handling some pretty challenging training. Second, it’s very well-established in a variety of populations (including both trained and untrained lifters) that moderate-load and low-load training produce similar hypertrophy, on average. That was the main point of intersection between the present study and the broader literature, and the results of the present study were perfectly in line with the broader literature. Third, the subjects clearly experienced a robust hypertrophy response: thigh lean soft tissue mass increased by an average of 0.7kg (7.6%) over 24 weeks of training. A 2020 meta-analysis found that whole-body lean mass increases by about 1.5kg (about 2.5%) after about 10 weeks of training, on average, in subjects between 18 and 40 years old (14). You can’t make a strict apples-to-apples comparison between those two figures – thigh lean soft tissue mass isn’t identical to whole-body lean mass, and 24 weeks is much longer than 10 weeks – but they’re certainly in the same general ballpark. Thus, while I’d certainly like to see these results replicated in other populations, I’m not too terribly concerned about a lack of generalizability. Next Steps I’d love to see the present results replicated in other populations. I’d also love to see this same study design applied to other training approaches. As just one of many potential possibilities, I’d love to see a study investigating whether people truly get desensitized to training volume over time. There’s a popular idea proposing that if your training volume creeps too high, you’ll be unable to continue building muscle if you try shifting to a lower-volume approach. A crossover study could investigate that claim. One group could perform 12 weeks of high-volume training (maybe 20 sets per muscle group per week), followed by 12 weeks of lower-volume training (maybe 10 sets per muscle group per week). Another group would complete the same blocks of training in the opposite order (lower volume followed by higher volume). The study could investigate total muscle growth over the full 24 weeks of training, and also examine whether the high-volumeto-low-volume group was unable to continue building muscle during the lower volume block of training. 20 APPLICATION AND TAKEAWAYS If moderate-load training isn’t helping you build muscle at the rate you’d like, lowload training might just help you get over your plateau. Even though low-load and moderate-load training are similarly effective at building muscle, on average, that doesn’t necessarily mean that your individual results will be similar with both approaches. The present study demonstrates that how well you respond to training at one intensity isn’t predictive of how well you’ll respond to training at a very different intensity. 21 References 1. Carneiro MAS, de Oliveira Júnior GN, Sousa JFR, Martins FM, Santagnello SB, Souza MVC, Orsatti FL. Different load intensity transition schemes to avoid plateau and noresponse in lean body mass gain in postmenopausal women. Sport Sci Health. 2022. https://doi.org/10.1007/s11332-022-00907-2 2. During the very first week of training, subjects only completed one set per exercise. They completed two sets per exercise in week 2. They completed three sets per exercise in the subsequent 22 weeks of training. 3. Altman DG, Royston P. The cost of dichotomising continuous variables. BMJ. 2006 May 6;332(7549):1080. doi: 10.1136/bmj.332.7549.1080. PMID: 16675816; PMCID: PMC1458573. 4. Beaven CM, Cook CJ, Gill ND. Significant strength gains observed in rugby players after specific resistance exercise protocols based on individual salivary testosterone responses. J Strength Cond Res. 2008 Mar;22(2):419-25. doi: 10.1519/JSC.0b013e31816357d4. PMID: 18550956. 5. Jones N, Kiely J, Suraci B, Collins DJ, de Lorenzo D, Pickering C, Grimaldi KA. A genetic-based algorithm for personalized resistance training. Biol Sport. 2016 Jun;33(2):117-26. doi: 10.5604/20831862.1198210. Epub 2016 Apr 1. PMID: 27274104; PMCID: PMC4885623. 6. Hammarström D, Øfsteng S, Koll L, Hanestadhaugen M, Hollan I, Apró W, Whist JE, Blomstrand E, Rønnestad BR, Ellefsen S. Benefits of higher resistance-training volume are related to ribosome biogenesis. J Physiol. 2020 Feb;598(3):543-565. doi: 10.1113/ JP278455. Epub 2020 Jan 15. PMID: 31813190. 7. Damas F, Angleri V, Phillips SM, Witard OC, Ugrinowitsch C, Santanielo N, Soligon SD, Costa LAR, Lixandrão ME, Conceição MS, Libardi CA. Myofibrillar protein synthesis and muscle hypertrophy individualized responses to systematically changing resistance training variables in trained young men. J Appl Physiol (1985). 2019 Sep 1;127(3):806-815. doi: 10.1152/japplphysiol.00350.2019. Epub 2019 Jul 3. PMID: 31268828. 8. Damas F, Barcelos C, Nóbrega SR, Ugrinowitsch C, Lixandrão ME, Santos LMED, Conceição MS, Vechin FC, Libardi CA. Individual Muscle Hypertrophy and Strength Responses to High vs. Low Resistance Training Frequencies. J Strength Cond Res. 2019 Apr;33(4):897-901. doi: 10.1519/JSC.0000000000002864. PMID: 30289872. 9. Lasevicius T, Ugrinowitsch C, Schoenfeld BJ, Roschel H, Tavares LD, De Souza EO, Laurentino G, Tricoli V. Effects of different intensities of resistance training with equated 22 volume load on muscle strength and hypertrophy. Eur J Sport Sci. 2018 Jul;18(6):772780. doi: 10.1080/17461391.2018.1450898. Epub 2018 Mar 22. PMID: 29564973. 10. Nóbrega SR, Ugrinowitsch C, Pintanel L, Barcelos C, Libardi CA. Effect of Resistance Training to Muscle Failure vs. Volitional Interruption at High- and Low-Intensities on Muscle Mass and Strength. J Strength Cond Res. 2018 Jan;32(1):162-169. doi: 10.1519/ JSC.0000000000001787. PMID: 29189407. 11. Counts BR, Buckner SL, Mouser JG, Dankel SJ, Jessee MB, Mattocks KT, Loenneke JP. Muscle growth: To infinity and beyond? Muscle Nerve. 2017 Dec;56(6):1022-1030. doi: 10.1002/mus.25696. Epub 2017 Jun 11. PMID: 28543604. 12. DE Camargo JBB, Brigatto FA, Braz TV, Germano MD, Nascimento GS, DA Conceição RM, Teixeira I, Sanches TC, Aoki MS, Lopes CR. Order of Resistance Training Cycles to Develop Strength and Muscle Thickness in Resistance-Trained Men: A Pilot Study. Int J Exerc Sci. 2021 Aug 1;14(4):644-656. PMID: 34567366; PMCID: PMC8439707. 13. Schoenfeld BJ, Grgic J, Ogborn D, Krieger JW. Strength and Hypertrophy Adaptations Between Low- vs. High-Load Resistance Training: A Systematic Review and Meta-analysis. J Strength Cond Res. 2017 Dec;31(12):3508-3523. doi: 10.1519/ JSC.0000000000002200. PMID: 28834797. 14. Benito PJ, Cupeiro R, Ramos-Campo DJ, Alcaraz PE, Rubio-Arias JÁ. A Systematic Review with Meta-Analysis of the Effect of Resistance Training on Whole-Body Muscle Growth in Healthy Adult Males. Int J Environ Res Public Health. 2020 Feb 17;17(4):1285. doi: 10.3390/ijerph17041285. PMID: 32079265; PMCID: PMC7068252. 15. The actual term used in the study was “thigh free-bone LBM.” I’m pretty sure they meant lean soft tissue mass of the thigh (all of the lean mass of the thigh, minus bone mass – lean soft tissue mass is the most common term for this), but I’m not 100% positive. █ 23 Study Reviewed: The Effect of Rest Interval Length on Upper and Lower Body Exercise in Resistance-Trained Females. Millender et al. (2022) Everything You Need to Know About Rest Intervals BY MICHAEL C. ZOURDOS Over the past decade, longer rest intervals have prevailed over shorter rest intervals in both research and practice for hypertrophy and strength. However, most of the rest interval data are from male lifters. Thus, a rest interval study in female lifters is a welcome addition to the literature. 24 KEY POINTS 1. In a crossover design, researchers examined the effects of rest interval length on rep performance and blood lactate responses. The lifters performed four sets to failure at 75% of their 10RM on the chest press and leg press with one and three minutes of interset rest. 2. Findings showed that the lifters better maintained rep performance and, thus, performed more total volume on the chest press (+33.01%) and leg press (+33.60%) in the three-minute than in the one-minute rest condition. There was no significant difference between conditions for the acute blood lactate response. 3. This study shows that longer interset rest leads to more volume than set-equated short rest interval training to failure. Overall, longer rest intervals are preferable to maximize short term volume and long term strength and hypertrophy. F or many years, short rest intervals (i.e., 30-90 seconds) were recommended to maximize muscle hypertrophy due to the substantial increase in anabolic hormones associated with short interset rest (i.e., the hormone hypothesis). However, a 2009 study from Buresh et al (2) showed no significant difference in muscle growth with 2.5- versus 1-minute rest intervals, but increases in arm cross-sectional area did tend to favor the 2.5-minute group. Nonetheless, the hormone hypothesis persisted, but, in 2016, a study from Schoenfeld et al (3) rocked hormone hypothesis defenders to their core. Schoenfeld et al found that, over eight weeks, trained men who rested three minutes between sets experienced greater lower body muscle growth and strength than men who rested for one minute between sets. The primary mechanism by which longer rest yields greater muscle growth is that longer interset rest allows lifters to maintain training loads better from set-to-set than shorter rest, thereby enabling more volume when sets are equated between short and long rest training. Additionally, many acute, crossover-design studies (4, 5, 6, 7, 8, 9) demonstrate that lifters can perform more volume with longer than shorter rest intervals. Although the data seem clear on this topic, all but one (10) of the acute studies examining rest interval length and rep performance in young individuals were conducted in male populations. Therefore, the presently reviewed study from Millender et al (1) on trained women is a welcome addition to the literature. Millender had 14 women perform four sets to failure at 75% of their 10-repetition maximum (RM) on the chest press and leg press, while resting for either one or three minutes between sets. The researchers assessed total volume performed and the acute blood lactate response. Unsurprisingly, the women performed significantly more volume on both the chest press (+33.01%) and leg press (+33.60%) in the three-minute rest condition; however, the blood lactate response did not differ between conditions. These findings confirm that set-to-set rep performance is better-maintained with longer rest intervals, 25 leading to more total volume when sets are equated between short and long rest training. Therefore, the simple interpretation is that lifters should use longer rest intervals of about three minutes. Although that simple interpretation is generally good advice, it’s a bit simplistic. Therefore, this article will aim to: compare volume performance and the acute blood lactate response to four sets to failure with 75% of a 10RM load on the chest press and leg press between short (one-minute) and long (three-minute) rest intervals in trained women. 1. Review the data examining the acute studies on rest interval length and volume performance. The researchers hypothesized that the rate of decline in reps would be uniform from set-to-set in both conditions, and total volume performance would be greater in the three-minute rest condition. No hypothesis was provided regarding the blood lactate response. However, gauging the introduction’s tone, it seems that the researchers expected a greater acute lactate response in the one-minute rest interval condition. 2. Review the longitudinal data on rest interval length, hypertrophy, and strength outcomes. 3. Discuss how volume and long term outcomes play out when sets are equated between short and long rest interval training to equate for total training session time. 4. Examine the rate of decline in reps from setto-set during both failure and non-failure training with short and long rest intervals and if this differs between men and women. 5. Determine appropriate rest intervals across different exercises and programming strategies. Purpose and Hypotheses Purpose The purpose of the reviewed study was to Hypotheses Subjects and Methods Subjects 14 women who had trained at least two times per week for at least one year completed the study. Additional subject details are in Table 1. Study Protocol All subjects completed this study over three days. On day one, subjects performed chest press and leg press 10RM testing. Subjects returned to the laboratory to complete two different experimental conditions; however, 26 the researchers did not specify the time between days in the study. In both conditions, subjects completed four sets to failure at 75% of 10RM (about 55% of 1RM) on the chest press, then, 30 minutes later, completed four sets to failure on the leg press also at 75% of 10RM. The only difference between conditions is that subjects rested three minutes between sets in one condition and one-minute between sets in the other condition. Outcome measures included total volume (sets × reps × load), reps per set, and the acute blood lactate response. Lastly, all reps were performed with a two second eccentric and a one second concentric. Findings Lifters performed more volume on both the chest press (+33.01%) and leg press (+33.60%) in the three-minute rest condition (Figure 2). Further, lifters performed more reps on sets two, three, and four in the three-minute condition than in the one-minute condition (Table 2). The blood lactate response was not significantly different between conditions. Lastly, the researchers did not report means and standard deviations. Thus, the volume percentages differences above and data in Table 2 are estimations extracted via WebPlotDigitizer from graphs in the published paper. 27 Criticisms and Statistical Musings without reaching momentary failure, it’s possible that lifters held back a little bit on the penultimate set to prepare for the last set. This study was pretty straightforward, but I’d like to bring up two minor points. First, there was minimal decrease in the number of reps performed from set three to set four in both conditions for both exercises. In fact, in the one-minute rest condition, there was a nominal increase of 1.33 reps, on average, from set three to set four. This finding is surprising since it’s expected that there would be a decrease in reps performed each set when training is performed to failure, and the same load is maintained. It’s hard to imagine performing sets to failure and performing slightly more reps on set four than on set three, especially if only resting one minute between sets. One explanation for this could be related to how the researchers defined failure: “failure was achieved if the subject voluntarily terminated the set, could not complete the concentric phase of the lift, broke their form to complete the concentric phase of the lift, or could not maintain the 2:1 cadence for two consecutive repetitions.” Therefore, since lifters could terminate sets voluntarily, even Second, the researchers assessed effort-based rating of perceived exertion after each set using the OMNI scale (11). The researchers noted that RPE after every set was between 8-10 (8 RPE was anchored to the descriptor “hard” while 10 RPE was anchored to “hardest exertion possible”). Since some sets were terminated at an 8 or 9 RPE, it is likely that some sets weren’t performed to momentary failure. Sets ending with an 8 RPE support the first point above that some lifters may have held back on the penultimate set. Additionally, the researchers did not statistically analyze the RPE values. Comparing the RPE values would have determined if the lifters perceived longer rest with more volume (three-minute condition) or shorter rest with less volume (one-minute condition) to be more difficult. Interpretation The reviewed study from Millender et al (1) is important to discuss because most acute 28 and longitudinal data pertaining to rest interval length come from male lifters. Further, although we have covered this topic before in MASS (one, two) there are some updates and nuances to discuss. This interpretation will cover the acute and longitudinal data to date and discuss how the literature shapes up for both women and men. Additionally, since most studies comparing rest interval lengths use failure training we’ll examine the rate of repetition decline from set-to-set across different exercises and loads in rest interval studies. There is only one previous acute study, to my knowledge, examining rest interval length for rep performance in young women (10) and one acute study for rep performance in older women (12). Additionally, one longitudinal study examined rest interval length in a mixed-sex cohort (13) and another longitudinal study solely in women (14). The present study was in concert with the existing body of literature on men (4, 5, 6, 7, 8, 9), showing that performance from set-to-set is better maintained with longer rest intervals when 29 training to failure. Table 3 summarizes acute crossover design interset rest studies comparing longer versus shorter rest intervals for rep performance. A portion of Table 3 (4, 5, 6, 7, 8, 9) was originally printed in Volume 4 Issue 5, and it has been significantly updated (1, 10, 12, 13) for this article. Table 3 paints a clear picture. That is, in both sexes, across different loads and reps ranges (3RM to >20RM), and on various exercises (squat, bench, chest press, leg press, flyes), performance is better maintained with longer interset rest. Therefore, if the number of sets is equated between rest interval lengths, more total volume will be performed with long rest intervals. Although this notion holds in both men and women, data from Ratamess (10) suggests that rep performance may be better maintained in women than in men during bench press sets at 75% of 1RM (Table 4). In Table 4, it appears that women had barely any decline in rep performance with three minutes rest, only lost one rep from sets 1-3 with two minutes rest, and two reps from sets 1-3 with one minute rest. On the other hand, male lifters from sets 1-3 lost ~2 reps, ~4 reps, and ~6 reps with three, two, and one minute of interset rest. Importantly, participants were told to perform “up to” 10 reps per set. Thus, the first set was likely not to failure for some participants, probably masking a more exacerbated decline in the number of reps performed from set-to-set. It’s also possible that women, on average, can perform more reps at a given relative load than men (at least at loads <70% of 1RM), which, in MEN HAD A LARGER DECREASE IN REPS FROM SET-TO-SET THAN WOMEN AT ALL DIFFERENT REST INTERVALS. 30 part, accounts for the higher number of total reps. However, any way you want to slice it, men had a larger decrease in reps from set-toset than women at all different rest intervals. The next set of findings from Ratamess was published in a different paper (15) but was part of the same study referenced in Table 4. Ratamess also had the women and men perform three sets of “up to” 10 reps at 75% of 1RM on the barbell incline bench press, barbell shoulder press, and bent over row following the bench press. In all conditions, subjects rested for two minutes between sets of assistance movements. The take home message for the assistance work is that both men and women tended to perform fewer reps on the first set of incline bench and shoulder press in the one-minute than in the three-minute rest condition, presumably due to lingering fatigue. However, the largest declines in rep performance from sets 1-3 occurred for women in the three-minute condition on the incline bench and for men in both the two- and three-minute conditions on the shoulder press. Overall, the data from Ratamess shows that women may be more resistant to fatigue than men during sets to failure (or close to failure). However, when a primary compound movement (bench press) is performed first, the rest interval for that primary compound movement is unlikely to affect total volume performance on subsequent assistance exercises. In a previous study from Willardson and Burkett (6), trained men performed four sets to failure with an 8RM load on both the squat and bench press. The rate of decline in reps from Williardson and Burkett can be seen in Table 5. In Willardson and Burkett, rep maintenance was again time-dependent; both the absolute (number of reps) and relative (%) decrease in rep performance from set-to-set was greater in the squat than the bench press at all interset rest intervals. Here’s a summary of the rate of decline in rep performance from set-to-set with various rest intervals in men and women based upon the data presented above: 31 1. Rep performance is better maintained on the bench press than the squat when training to failure. 2. Women have slightly lower decreases in reps from set-to-set than men across all rest intervals with moderate reps (i.e., 8-10). 3. Men lose about 2-3 reps per set, with 1-minute of interset rest and 1-3 reps per set with 2-3 minutes of interset rest with moderate reps. 4. Women lose about 1-2 reps per set with 1-minute of interset rest at moderate loads. 5. Women lose, on average, <1 rep per set when resting ≥ 2 minutes. I should stress that the decline in rep performance is likely individual and exercise-dependent; thus, the above take homes are not blanket statements to be applied across the board. Also, the study from Ratamess likely did not cause most women to train to failure 32 on the first set, and some likely did not reach failure on the second set, meaning the rate of rep decline is higher than observed. I also don’t find the lack of group differences for blood lactate in the presently reviewed study especially important. In Hill-Haas et al (14), 20-second rest intervals did lead to a greater acute blood lactate response than 80-second rest intervals. However, others comparing the acute blood lactate response between one and three minutes (16), and 30 seconds, one minute, and two minutes (17 MASS Review) of interset rest have shown no significant difference in the blood lactate response, despite subjects performing more volume in the longer rest interval conditions. Most importantly, the one-minute rest condition in the presently reviewed study still performed fewer reps despite a lack of difference in the blood lactate response between conditions. Although some studies show no difference between short and long rest intervals for hypertrophy (16, 18) and strength (13, 16, 18), others do favor long rest intervals for hypertrophy (2, 3) or strength (14). Similar to the acute literature, the data are mostly relegated to men. Studies from Longo et al. (13 - MASS Review) and Hill-Hass (14) enrolled women, but these women were not resistance trained. A summary of these longitudinal studies is in Table 6. With the exception of one study on older men (19), Table 6 shows that the longitudinal data mostly tracks the acute data. In other words, some studies favor longer rest intervals for strength and hypertrophy, and some are neutral. Regarding studies in women, Hill-Haas showed that longer rest intervals led to greater strength gain. However, these longer rest intervals in Hill-Haas were only 80 seconds compared to a shorter interval of 20 seconds. This comparison still shows the concept of longer rest intervals allowing the maintenance of performance from set-to-set and better long term outcomes. The Longo study used a mixed-sex cohort, and was the first study to equate for volume between long and short rest by adding sets to the short rest interval protocol. In practice, the purpose of taking short instead of long rest and performing more sets would be to save total training time. However, as Greg previously illustrated, this strategy doesn’t save that much time. Short rest intervals still have their place when true time-efficient strategies, such as restpause training and agonist/antagonist supersets, are used. Further, not all exercises need the same rest intervals. Three to five-minute, or even longer, rest intervals may be used on major movements (i.e., squat, bench press, and deadlift), but are hardly ever necessary on some assistance movements (i.e., biceps curls, triceps extensions, lateral raises). Lastly, while recommendations such as 3-5+ minutes of interset rest for major movements, and 2-3-minute rest intervals for most assistance movements, are reasonable suggestions, I don’t think lifters need to have their eyes glued to a stopwatch between sets. We’ve reviewed studies in MASS showing the efficacy of self-selected rest intervals. Specifically, Ibbot et (20 - MASS Review) observed that, when resting intuitively, trained men selected, on average, 4-5-minute 33 rest intervals and completed nearly 100% of the volume when prescribed 5 × 5 at a 5RM on squats. Simao et al (21 - MASS Review) found that trained men selected rest intervals of ~90-133 seconds across various exercises to failure at 75% of 1RM over an 8-week training study. Simao also had another group rest exactly 75 seconds between all sets, and found that the self-selected group performed more reps throughout the training study. Additionally, de Salles et al (22) reported that, when performing three sets to failure at 75% of 1RM on the squat, bench press, leg press, and biceps curl, subjects performed a similar number of total repetitions with two minutes of interset rest versus a self-selected rest interval. The average self-selected rest intervals from de Salles were: 104.74 (squat), 117.07 seconds (leg press), 115.84 seconds (bench press), and 102.67 seconds (biceps curl). Overall, I think it’s a good idea to know how long you’ve generally been resting, but staring at a clock isn’t necessary, and you’ll probably know when you’re good to go. IT’S A GOOD IDEA TO KNOW HOW LONG YOU’VE GENERALLY BEEN RESTING, BUT STARING AT A CLOCK ISN’T NECESSARY, AND YOU’LL PROBABLY KNOW WHEN YOU’RE GOOD TO GO. Next Steps I’d like to see a study comparing shorter (two-minute) versus longer (five-minute) rest intervals with high volume non-failure training. For example, researchers could split lifters into two groups using the same RIR prescription for 10 weeks (or another longitudinal time frame) but different rest intervals. Specifically, both groups could train sets to a 1-3 RIR, but one group could take two minutes rest, and the other group could take five minutes of interset rest. Researchers could measure muscle size and strength before and after the study. The overarching purpose of the proposed study would be to see if the longer rest interval group would maintain a higher load and more volume, and if that advantage led to enhanced strength and hypertrophy. Of course, other rest interval comparisons could be made, such as one versus three minutes, or a wider comparison of one versus five minutes. While I think either of these comparisons (1 vs. 3 minutes or 1 vs. 5 minutes) would lead to greater volume and long term adaptations with the longer rest intervals, I don’t think many trained lifters take only one minute between sets on the squat or bench press. Therefore, I’d opt for the more ecologically valid comparison of two versus five minutes. 34 APPLICATION AND TAKEAWAYS 1. Millender et al (1) found that lifters who performed four sets to failure with 75% of their 10RM (~55% of 1RM) on the chest press and leg press better maintained rep performance from set-to-set with three versus one minute of interset rest. 2. When the number of sets is equated, and sets are taken to failure, longer rest intervals enhance volume performance, and women, on average, tend to maintain rep performance from set-to-set better than men. Also, longitudinal studies tend to show that longer rest intervals lead to greater hypertrophic and strength outcomes than shorter rest intervals when the number of sets are equated. 3. When comparing two different rest interval lengths (i.e., three versus one minute), choosing the longer interval for both acute rep performance and long-term outcomes is preferable. However, there is a point of diminishing returns for rest interval length. Further, short rest intervals still have their place in various programming strategies, such as rest-pause and agonist-antagonist superset training. 35 References 1. Millender DJ, Mang ZA, Beam JR, Realzola RA, Kravitz L. The Effect of Rest Interval Length on Upper and Lower Body Exercises in Resistance-Trained Females. International Journal of Exercise Science. 2021;14(7):1178-91. 2. Buresh R, Berg K, French J. The effect of resistive exercise rest interval on hormonal response, strength, and hypertrophy with training. The Journal of Strength & Conditioning Research. 2009 Jan 1;23(1):62-71. 3. Schoenfeld BJ, Pope ZK, Benik FM, Hester GM, Sellers J, Nooner JL, Schnaiter JA, Bond-Williams KE, Carter AS, Ross CL, Just BL. Longer inter-set rest periods enhance muscle strength and hypertrophy in resistance-trained men. Journal of strength and conditioning research. 2016 Jul 1;30(7):1805-12. 4. Hernandez DJ, Healy S, Giacomini ML, Kwon YS. 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The effect of rest interval length on the sustainability of squat and bench press repetitions. Journal of Strength and Conditioning Research. 2006 May 1;20(2):400. 9. Scudese E, Willardson JM, Simão R, Senna G, de Salles BF, Miranda H. The effect of rest interval length on repetition consistency and perceived exertion during near maximal loaded bench press sets. The Journal of Strength & Conditioning Research. 2015 Nov 1;29(11):3079-83. 10. Ratamess NA, Chiarello CM, Sacco AJ, Hoffman JR, Faigenbaum AD, Ross RE, Kang J. The effects of rest interval length on acute bench press performance: The influence of gender and muscle strength. The Journal of Strength & Conditioning Research. 2012 Jul 36 1;26(7):1817-26. 11. Robertson RJ, Goss FL, Rutkowski JA, Lenz BR, Dixon C, Timmer J, Frazee KR, Dube J, Andreacci JO. Concurrent validation of the OMNI perceived exertion scale for resistance exercise. Medicine and science in sports and exercise. 2003 Feb 1;35(2):33341. 12. Jambassi Filho JC, Gurjão AL, Prado AK, Gallo LH, Gobbi S. Acute effects of different rest intervals between sets of resistance exercise on neuromuscular fatigue in trained older women. The Journal of Strength & Conditioning Research. 2020 Aug 1;34(8):223540. 13. Longo AR, Silva-Batista C, Pedroso K, de Salles Painelli V, Lasevicius T, Schoenfeld BJ, Aihara AY, de Almeida Peres B, Tricoli V, Teixeira EL. Volume load rather than resting interval influences muscle hypertrophy during high-intensity resistance training. J Strength Cond Res. 2020 Jun 10. 14. Hill-Haas S, Bishop D, Dawson B, Goodman C, Edge J. Effects of rest interval during high-repetition resistance training on strength, aerobic fitness, and repeated-sprint ability. Journal of sports sciences. 2007 Apr 1;25(6):619-28. 15. Ratamess NA, Chiarello CM, Sacco AJ, Hoffman JR, Faigenbaum AD, Ross RE, Kang J. The effects of rest interval length manipulation of the first upper-body resistance exercise in sequence on acute performance of subsequent exercises in men and women. The Journal of Strength & Conditioning Research. 2012 Nov 1;26(11):2929-38. 16. Fink JE, Schoenfeld BJ, Kikuchi N, Nakazato K. Acute and long-term responses to different rest intervals in low-load resistance training. International journal of sports medicine. 2017 Feb;38(02):118-24. 17. Lopes CR, Crisp AH, Schoenfeld B, Ramos M, Germano MD, Verlengia R, da Mota GR, Marchetti PH, Aoki MS. Effect of rest interval length between sets on total load lifted and blood lactate response during total-body resistance exercise session. Asian Journal of Sports Medicine. 2018 Jun 1;9(2). 18. Ahtiainen JP, Pakarinen A, Alen M, Kraemer WJ, Häkkinen K. Short vs. long rest period between the sets in hypertrophic resistance training: influence on muscle strength, size, and hormonal adaptations in trained men. The Journal of Strength & Conditioning Research. 2005 Aug 1;19(3):572-82. 19. Villanueva MG, Lane CJ, Schroeder ET. Short rest interval lengths between sets optimally enhance body composition and performance with 8 weeks of strength resistance training in older men. European journal of applied physiology. 2015 Feb;115(2):295-308. 37 20. Ibbott P, Ball N, Welvaert M, Thompson KG. Variability and Impact of Self-Selected Interset Rest Periods During Experienced Strength Training. Perceptual and motor skills. 2019 Jun;126(3):546-58. 21. Simão R, Polito M, de Salles BF, Marinho DA, Garrido ND, Junior ER, Willardson JM. Acute and Long-Term Comparison of Fixed vs. Self-Selected Rest Interval Between Sets on Upper-Body Strength. The Journal of Strength & Conditioning Research. 2022 Feb 1;36(2):540-4. 22. De Salles BF, Polito MD, Goessler KF, Mannarino P, Matta TT, Simão R. Effects of fixed vs. self-suggested rest between sets in upper and lower body exercises p █ 38 Study Reviewed: Changes in Intra-to-Extra-Cellular Water Ratio and Bioelectrical Parameters from Day-Before to Day-Of Competition in Bodybuilders: A Pilot Study. Nunes et al. (2022) Can Bodybuilders Change Their Intra-to-Extracellular Water Ratio During Peak Week? BY ERIC HELMS More research is steadily published examining the “peak week” methods bodybuilders use in attempts to acutely enhance stage appearance. This study assesses a potential mechanism behind many peaking methods: manipulating one’s intra-to-extracellular water ratio. 39 KEY POINTS 1. Bodybuilders acutely manipulate nutrition in the days prior to and day of getting on stage in an attempt to enhance appearance. One purported mechanism of enhancing appearance is increasing the intra-to-extracellular water ratio. 2. The authors of this study evaluated this claim by measuring changes in intrato-extracellular water ratio with bioelectrical impedance as well as upper arm, waist, and thigh circumference among 11 bodybuilders the day prior to, and day of competition. 3. Intra-to-extracellular water ratio likely increased, as did upper arm circumference, while waist circumference decreased. However, we can’t attribute specific peaking practices to these outcomes nor directly confirm that these changes enhanced appearance. T he present study (1) is the latest in a series of recent publications investigating the methods physique athletes use in the days prior to and on the day of competition to enhance appearance. I’ve covered this topic multiple times in MASS. In Volume 1, I made a video on the limited research and the physiological principles that can be applied to peaking. In Volume 3, I reviewed a survey that comprehensively investigated the peaking methods of 81 natural physique athletes in the UK (2), and in the next issue we were fortunate enough to have the authors of that survey provide their thoughts on the study’s findings as bonus content. Most recently, in Volume 4, I reviewed a quasi-experimental study that compared anthropometric differences and differences in photo silhouette scores from bodybuilding judges between competitors who practiced carbohydrate loading, versus those who did not (3). I’ve been intrigued as this body of evidence moves from theoretical, to observational, to quasi-experimental, and this latest study steps sideways to look at a potential mechanism of action. For background, many peaking strategies are purported to increase the intra-to-extracellular water ratio; supposedly reducing subcutaneous water and increasing muscle-cell hydration, theoretically enhancing appearance. To investigate this claim, the present study evaluated changes in upper arm, thigh, and waist circumference as well as the intra-to-extracellular water ratio with single-frequency bioelectrical impedance in 11 male bodybuilders from the day prior to the day of competition. Indeed, compared to the day prior, the bodybuilders experienced a significant decrease in waist circumference, total body water, and extracellular water, and an increase in upper arm circumference and intracellular water, resulting in an increased intra-to-extracellular water ratio on the day of competition. In this review I’ll discuss the limitations of these findings, what they do and don’t tell us, and what the next steps should be to advance peaking research. 40 Purpose and Research Questions Purpose The authors of the present study “aimed to evaluate changes in body water fractions and BIA [bioelectrical impedance] parameters from the day-before to day-of competition in bodybuilders.” Hypothesis The authors “hypothesized that TBW [total body water] and ECW [extracellular water] would decrease, ICW [intracellular water] would increase, and R and Xc [metrics inversely related to TBW and representing muscle cell membrane integrity, quality, and density, respectively] would increase.” Subjects and Methods Subjects Out of 50 male and female athletes invited to participate in this study, 11 male bodybuilders volunteered (more on the relevance of this in the discussion). These bodybuilders had the following demographic characteristics: age = 28.8 ± 4.1 years (range: 22–35); weight = 80.5 ± 7.9 kg; height = 172.0 ± 7.2 cm; body mass index = 27.2 ± 1.9 kg/m2; prior competitions = 6 ± 4. One bodybuilder competed in the junior category (≤ 23 years-old, ≥ 75 kg) while the remaining 10 competed in the open category of both the men’s physique and bodybuilding divisions across various weight classes (men’s physique = 5; men’s bodybuilding = 5). Study Design and Assessments This study was conducted over two days, the day prior to competition and the day of competition. The participants were amateur competitors at a state-level bodybuilding competition sanctioned by the International Federation of Bodybuilding and Fitness (IFBB). The day prior to competition, the participants reported to the contest venue for their official weigh-ins, and then the researchers measured their waist, right-side upper-arm, and mid-thigh circumferences, and obtained a self-reported height. Following anthropometry, single frequency phase-sensitive bioelectrical impedance was used to assess foot-to-hand body water metrics following standardized lab procedures to ensure accuracy. These measurements were then repeated the following day, the day of competition, before the “warm-up” (I assume the authors meant before pumping up) prior to prejudging. All 11 competitors agreed to take part in the bioimpedance analysis, but only eight agreed to have their circumferences measured. Notably, while the authors reported low variability using their standardized lab techniques for bioimpedance, these measurements were carried out after the athletes had fasted for a minimum of 1.5 hours. Previously validated equations were used to estimate total, intracellular, and extracellular body water (see the Criticisms and Statistical Musings section for details on the equations). Findings Given the relevance of the findings to the focus of MASS, I’ll focus primarily on the 41 circumference measurements and the main bioelectrical impedance findings, total body water, intracellular water, and extracellular water, rather than getting into the “raw” bioimpedance outcomes from which these data were estimated. Circumferences and Bodyweight From the day prior to the day of the contest, the competitors experienced significant decreases in waist circumference (79.3 ± 3.2 cm to 78.6 ± 2.8 cm; p = 0.036; effect size = −0.21) and increases in upper-arm circumference (36.1 ± 1.5 cm to 36.8 ± 1.5 cm; p = 0.028; effect size = 0.40), and no significant change in thigh circumference (56.6 ± 2.6 cm to 56.2 ± 2.0 cm; p = 0.468; effect size = −0.14) or bodyweight (80.8 ± 7.9 kg to 80.2 ± 8.0 kg; p = 0.158; effect size = −0.07). Body Water As shown, there were significant decreases in total body (51.4 ± 4.6 L to 50.3 ± 4.2 L; p = 0.028; effect size = −0.22) and extracellular water (19.8 ± 1.8 L to 17.2 ± 1.4 L; p < 0.001; effect size = −1.39) and a significant increases in intracellular water (31.6 ± 2.9 L to 33.1 ± 2.8 L; p < 0.001; effect size = 0.50), resulting in significant increases in both the intra-to-extracellular water ratio (1.60 ± 0.03 L to 1.92 42 ± 0.01 L; p < 0.001) as well as the intracellular-to-total body water ratio (0.61 ± 0.01 L to 0.66 ± 0.01 L; p < 0.001). Notably, all but one participant experienced decreases in total body water, while all 11 participants increased intracellular and decreased extracellular water. Criticisms and Statistical Musings What follows is one minor point that will help you better understand its limitations – but doesn’t fundamentally change the interpretation of this study – and one major point on methodology that potentially does. First, like almost all studies on physique athletes, this study has a small sample size, limiting our ability to generalize the findings to the broader population of physique competitors. This is no fault of the authors, and their paper hints at just how difficult it is to recruit dedicated athletes in close proximity to competition. Specifically, of the 50 competitors invited to participate, only 11 agreed. Further, in the grand scheme of research, this was an incredibly non-invasive study. The researchers simply made observations, they didn’t manipulate the participants’ nutrition or training, and the measurements didn’t require blood draws, fatiguing exercise tests, or long personal questionnaires about eating behavior or body image. All the researchers wanted was to take body circumference and bioimpedance measurements on two consecutive days, which I suspect took, at most, 3045 minutes on each day. Further, the researchers didn’t require the participants to come to the lab; rather, they were at the competition venue. Despite that, only 11 agreed to participate, and of those 11, three opted out of the circumference measurements. This is not because bodybuilders are selfish or anti-science, as even I would have hesitated to participate in this study. The second measurements were taken on the day of competition, before the pump-up, immediately before getting on stage. From a scientific perspective, it might have been beneficial to select this time point to avoid the acute effect of the pump-up routine on water balance. But, from a competitor’s perspective, I’d be really nervous that I’d miss, or have to rush, my pump-up, or, at worst, miss my stage time and get disqualified. Also, I can understand not wanting to get circumference measurements; depending on the type of stage color you use, the tape measure could smudge it, and potentially impact your appearance. All this is to say, it’s a challenge to get high quality data on physique athletes close to competition. Moving on to the major limitation, the authors assessed body water in a dynamic state, in a very unique population, using single frequency bioelectrical impedance. As reviewed, peaking strategies differ between athletes as to whether more or less carbs are consumed, whether alcohol is or isn’t consumed on show day, whether water is restricted or not (or loaded then restricted), whether diuretics are or aren’t used (herbal or potentially prescription in the case of the present study’s non-tested competitors), and whether other dehydration techniques are implemented or not. These differences also exist within athletes on different days as they progress through their peaking plans. To increase the 43 validity and reliability of body composition testing via bioimpedance, efforts to control hydration status are recommended, such as taking measurements after an overnight fast, at the same time of day, after a similar prior day of eating and drinking, and at a similar proximity to the last training session (4). These best practices, which couldn’t occur in the present study, are encouraged due to the limitations of bioelectrical impedance, as changes in hydration can impact body composition measurements. Bioimpedance estimates body composition using assumptions about the hydration of different body tissues, and by measuring the body’s resistance to electrical current. However, this is all to improve the validity and reliability of body composition measurements, not measurements of body water. Certainly, you might think that bioimpedance measurements of body water are more robust to variation than measurements of body composition, as the typical view is that bioimpedance estimates body composition by “measuring” body water. However, bioelectrical impedance estimates body water from electrical resistance, then uses those (estimated) values to estimate body composition. Thus, estimations occur at all levels, even for the measurement of body water. Thus, the efforts to control hydration status and proximity to exercise that are important for body composition measurements are equally important for body water measurements. To improve upon these issues, instead of single-frequency bioimpedance, researchers can utilize multi-frequency alternatives like multi-frequency bioelectrical imped- ance analysis or bioimpedance spectroscopy, which use multiple frequencies ranging from low (which don’t penetrate cell membranes, and only pass through extracellular fluid volume) to high (which do penetrate cell membranes, and therefore pass through extra and intracellular fluid volume). By utilizing a combination of high and low frequency currents, multi-frequency alternatives allow the tester to distinguish between intracellular and extracellular fluid volume (5). In contrast, the presently reviewed study used a single-frequency device, which does a poor job of precisely detecting changes in total body water (6), and makes no direct distinction between intracellular and extracellular fluid compartments. For this reason, the authors used previously published equations for estimating fluid compartments in athletes (7). Moreso, the researchers who developed these equations obtained their data under best-case-scenario conditions by testing after an overnight fast lasting at least 12 hours, at least 15 hours from the last exercise session, in a confirmed euhydrated state. Even in such ideal conditions, “TBW could be over- or underestimated by ~5.6 kg, ECW could be underestimated by ~3.6 kg or overestimated by ~4 kg, and ICW could be over- or underestimated by ~6 kg (7).” These ideal conditions, through no fault of the present study’s authors, simply weren’t possible, as the aim was to observe the effect of manipulating these variables. The bodybuilders were definitely not euhydrated, may or may not have trained recently (some physique competitors do a light session one-day out), and were only fasted for “at least” 1.5 hours, likely due to carb loading. On top of these issues, the fact that the 44 participants were bodybuilders creates a problem. The equation the authors used was specifically based on a mixed-sex sample of team sport, endurance, track and field (sprinters, hurdlers, and jumpers), and combat athletes. According to the creators of the equation, they developed it because “Athletes differ from the general population specifically with sport-specific differences in body geometry, that almost always are ignored by researchers despite awareness that geometry is a factor affecting bioimpedance measurements, and that BIA prediction equations are sample-specific (7).” Likewise, you’d expect bodybuilders’ body geometry to differ meaningfully from this cohort of athletes. Ultimately, single frequency devices and estimation equations are much less accurate for estimating changes in body water when dealing with abnormally altered hydration states where interindividual differences in lean tissue hydration are potentially too high for the uniform estimation equations to accurately represent intracellular or extracellular water volumes (8). Just how abnormal were the hydration states of the competitors in this study? Well, the authors actually noted that the phase angle (the raw variable representing an index of the ratio between extracellular and intracellular water) of this group of competitors was the highest ever observed in the literature, and that the phase angle of the participant on competition day with the highest score was the highest individual value ever reported in the literature, which was 4.4 standard deviations above the reference value for lean male athletes. In short, very abnormal. With that said, I don’t think this completely invalidates the present study’s findings. These bodybuilders probably did have high intra-to-extracellular water ratios, higher than most “normal” conditions, and this, in combination with the use of single-frequency bioelectrical impedance and unstandardized conditions, are the sources of this major limitation. In such abnormal conditions, with extreme body geometries, using equations that don’t represent the studied population, we’re likely to see variability and errors in measurement. Thus, I disagree with the authors’ suggestion that bioelectrical impedance derived intra-to-extracellular water ratios can be used to assess the effectiveness of a peaking strategy. The variability from the aforementioned reasons causes too much error for within-individual day-to-day comparisons (in addition to the fact that the intra-to-extracellular water ratio may not be a proxy for appearance improvement, which I discuss in the interpretation). In fact, in such a dynamic state, accurately measuring intra-to-extracellular water ratios may only be possible with multiple, complementary assessment methods beyond impedance testing to assess hydration status (9). So, what’s the take home of this section? For one, the specific values in the results may not be that accurate based on the variability associated with the methods and population, but I’d venture a guess that the directionality of the changes is probably accurate. Meaning, I think the bodybuilders might have increased their intra-to-extracellular water ratio, but, to know for sure, and to what degree, we need follow up studies with more rigorous methods. Also, we have to take a step back from 45 the authors’ suggestion of using bioelectrical impedance as a tool to assess individual peaking success, at least with single-frequency bioelectrical impedance. Instead we should just look at the present study as tentative proof that intra-to-extracellular water ratios can change in response to peaking, which is primarily what this paper is about anyway. Interpretation A huge part of the vernacular of assessing physiques in the bodybuilding world are comments on how “dry,” “separated,” “hard,” or “grainy” athletes look. If you’re a scientist and a bodybuilder like me, you end up with a love-hate relationship with these terms. Sure, they can be apt descriptions of what a physique looks like, and I get excited when I see physiques that exemplify these descriptions, but, at the same time, I can’t know if the terms accurately describe the physiological state, nor the cause, associated with that look. For example, many times I’ve seen extremely lean competitors who drank a ton of water on show day get described as “dry,” likely because they are lean and full enough (presumably from carbohydrate loading, which can enhance the appearance of muscularity [3]), and got a good pump, such that there’s nothing but stretched skin to obscure their muscularity, producing a hard, grainy, separated, and “dry” look, despite the fact that they are well-hydrated. Likewise, I’ve seen competitors who restricted their water intake get described as “watery,” potentially because they weren’t lean enough to look hard, and/or potentially because their blood pressure was too low, and they couldn’t get a good pump, leaving them looking “watery” even while dehydrated, because their water balance was out of whack. But, ultimately, all of this is supposition, and this supposition is a continual source of contention between bodybuilders who put faith in traditional peaking theory (which I discuss in depth HERE) and science-minded bodybuilders, who are skeptical of some of these claims. That’s where the present study comes in. A common claim among bodybuilders is that the traditional peaking process manipulates fluid shifts which increase intracellular water retention, while reducing extracellular water retention, increasing the intra-to-extracellular water ratio, which has a beneficial effect on appearance. A common sciency response to this claim is that intra-to-extracellular fluid balance is tightly regulated, and can’t be manipulated to any significant extent, and I’ll admit it, I’ve said as much. However, I think the present study might (see the criticisms section) establish that this sciency response is perhaps too sweeping, and that bodybuilders may be able to manipulate their intra-to-extracellular water ratio in the way they intend. In fact, every single participant in this study BODYBUILDERS MAY BE ABLE TO MANIPULATE THEIR INTRA-TO-EXTRACELLULAR WATER RATIO IN THE WAY THEY INTEND. 46 decreased their extracellular water while simultaneously increasing their intracellular water from the day prior to the day of the competition. This finding may be an important step in understanding what is happening physiologically during the peaking process. However, we have to fight against the urge to over extrapolate based on it. First, it’s important to note that intracellular is not synonymous with intramuscular, and that extracellular is not synonymous with subcutaneous. This is an important distinction from an appearance standpoint. For example, extracellular water retention within muscle, should enhance appearance. Anecdotally, I look more muscular in some muscle groups during the days after I train, perhaps due to intramuscular (but not necessarily intracellular) muscle damage-related edema. Indeed, the time course of acute muscle swelling in response to resistance training is roughly 48-72 hours (10), which is why researchers typically wait this long before assessing changes in muscle thickness, so they aren’t erroneously characterizing swelling as hypertrophy. Further, the vascular system is extracellular, but, theoretically, you wouldn’t want a fluid reduction in the vascular system as this would make it harder for blood to be delivered to your muscles while pumping up. All in all, just because bodybuilders might be able to increase their intra-to-extracellular water ratio, doesn’t mean it has a positive effect on appearance in all cases, or that appearance improves commensurate with this ratio. The next point worth highlighting is that all the competitors increased their intra-to-extracellular water ratio. I find this interesting, because there is a lot of variability in approaches JUST BECAUSE BODYBUILDERS MIGHT BE ABLE TO INCREASE THEIR INTRA-TO-EXTRACELLULAR WATER RATIO, DOESN’T MEAN IT HAS A POSITIVE EFFECT ON APPEARANCE IN ALL CASES. to peaking. Not all competitors carb load (3), and not all competitors manipulate hydration, and, of the competitors who do, they don’t all do it the same way or to the same magnitude (2). Further, in my experience, some bodybuilders do indeed mess up their appearance with their peaking strategies. So while it’s possible the researchers recruited 11 competitors who improved their appearance, I think it’s unlikely, and, considering they all increased their intra-to-extracellular water ratio, I question the notion that such an increase is a perfect proxy for an improvement in appearance (assuming the measurements were accurate). Ultimately, we don’t know any details about the competitors’ peaking strategies in the present study; we just know they probably increased their intra-to-extracellular water ratio. Thus, unfortunately, we simply can’t attribute any specific, individual peaking practice to the body water changes observed in this study. To conclude, body- 47 APPLICATION AND TAKEAWAYS The peak week approaches that bodybuilders use might result in acute increases in intra-to-extracellular water ratios that are higher on contest day than the day prior. Thus, there may be some accuracy to the claims that some combination of water, electrolyte, and carbohydrate manipulation meaningfully change these ratios. However, the specific methods that increase these ratios, and the degree to which an increase enhances appearance, if it does at all, is yet to be determined. builders may be increasing their intra-to-extracellular water ratios, but whether this is a good thing that scales with improvements in appearance, or what specific practices increase this ratio, is unknown. Next Steps As I mentioned in the interpretation, this is a cool mechanistic study that indicates bodybuilders are actually doing what they intend BODYBUILDERS MAY BE INCREASING THEIR INTRATO-EXTRACELLULAR WATER RATIOS, BUT WHETHER THIS IS A GOOD THING THAT SCALES WITH IMPROVEMENTS IN APPEARANCE, OR WHAT SPECIFIC PRACTICES INCREASE THIS RATIO, IS UNKNOWN. during peak week, physiologically speaking. However, the missing link is whether this physiological change commensurately impacts bodybuilders’ appearance the way they think it does. To investigate this, the methods of the present study (but using multi-frequency bioelectrical impedance analysis or bioimpedance spectroscopy, or even more direct reference methods, such as deuterium dilution and bromide dilution) could be combined with elements of the last study on carb loading I reviewed (3), where the researchers had bodybuilding judges score photos of the participants, while blinded to whether the photos were taken before or after carb loading. If changes in appearance could be quantified, as well as changes to intra-to-extracellular water ratios, while the peaking methods of the participants were documented, you could actually see which methods resulted in positive changes in appearance, and whether they coincided with increases in intra-to-extracellular water ratios. 48 References 1. Nunes, J. P., Araújo, J., Ribeiro, A. S., Campa, F., Schoenfeld, B. J., Cyrino, E. S., et al. (2022). Changes in Intra-to-Extra-Cellular Water Ratio and Bioelectrical Parameters from Day-Before to Day-Of Competition in Bodybuilders: A Pilot Study. Sports (Basel, Switzerland), 10(2), 23. 2. Chappell, A. J., & Simper, T. N. (2018). Nutritional Peak Week and Competition Day Strategies of Competitive Natural Bodybuilders. Sports (Basel, Switzerland), 6(4), 126. 3. de Moraes, W., de Almeida, F. N., Dos Santos, L., Cavalcante, K., Santos, H. O., Navalta, J. W., et al. (2019). Carbohydrate Loading Practice in Bodybuilders: Effects on Muscle Thickness, Photo Silhouette Scores, Mood States and Gastrointestinal Symptoms. Journal of Sports Science & Medicine, 18(4), 772–779. 4. Androutsos, O., Gerasimidis, K., Karanikolou, A., Reilly, J. J., & Edwards, C. A. (2015). Impact of eating and drinking on body composition measurements by bioelectrical impedance. Journal of Human Nutrition and Dietetics, 28(2), 165–171. 5. Marra, M., Sammarco, R., De Lorenzo, A., Iellamo, F., Siervo, M., Pietrobelli, A., et al. (2019). Assessment of Body Composition in Health and Disease Using Bioelectrical Impedance Analysis (BIA) and Dual Energy X-Ray Absorptiometry (DXA): A Critical Overview. Contrast Media & Molecular Imaging, 2019, 3548284. 6. Ugras S. (2020). Evaluating of altered hydration status on effectiveness of body composition analysis using bioelectric impedance analysis. The Libyan Journal of Medicine, 15(1), 1741904. 7. Matias, C. N., Santos, D. A., Júdice, P. B., Magalhães, J. P., Minderico, C. S., Fields, D. A., et al. (2016). Estimation of total body water and extracellular water with bioimpedance in athletes: A need for athlete-specific prediction models. Clinical Nutrition, 35(2), 468–474. 8. Kyle, U. G., Bosaeus, I., De Lorenzo, A. D., Deurenberg, P., Elia, M., Manuel Gómez, J., et al. (2004). Bioelectrical impedance analysis-part II: utilization in clinical practice. Clinical Nutrition, 23(6), 1430–1453. 9. Armstrong L. E. (2007). Assessing hydration status: the elusive gold standard. Journal of the American College of Nutrition, 26(5 Suppl), 575S–584S. 10. Ogasawara, R., Thiebaud, R. S., Loenneke, J. P., Loftin, M., & Abe, T. (2012). Time course for arm and chest muscle thickness changes following bench press training. Interventional Medicine & Applied Science, 4(4), 217–220. █ 49 Study Reviewed: Autonomy Support in Sport and Exercise Settings: A Systematic Review and Meta-Analysis. Mossman et al. (2022) Coaching Beyond the Spreadsheet: How (and Why) To Promote Intrinsic Motivation BY ERIC TREXLER A lot of evidence-based coaches and fitness enthusiasts invest considerable time and effort into optimizing the nuts and bolts of their programs. A new meta-analysis on psychological aspects of coaching suggests that there are ample opportunities (beyond the spreadsheet) to enhance a lifter’s long-term success and well-being. 50 KEY POINTS 1. The presently reviewed meta-analysis sought to quantify associations between coach autonomy support and a wide range of outcomes related to their clients’ or athletes’ experiences. 2. Autonomy support was correlated with a wide range of positive outcomes, including satisfaction of psychological needs, intrinsic motivation, general well-being, positive affect, life satisfaction, self-esteem, performance and achievement, effort, and athlete-coach relationship quality. 3. Self-determination theory yields some very simple and practical strategies that can facilitate the successful implementation of a great program, ultimately supporting a lifter’s subjective experience, general well-being, and intrinsic motivation, which can provide a solid foundation for long-term success. A lot of MASS readers coach others in pursuit of goals related to fitness or athletics. Conversely, many MASS readers are coached by someone else. Even if you don’t formally identify as a coach or a client (or both), you inevitably take part in the process of coaching yourself. As such, knowledge about effective coaching practices has tremendous utility, whether you’re using it to improve the coaching services you provide, evaluate the coaching services you receive, or reassess the strategies and tools you use when coaching yourself. Self-determination theory is used in several motivation-related applications of psychology, such as behavior change and athletic performance. It posits that people have a desire for personal growth, and that repeated instances of self-improvement, goal attainment, and skill mastery positively impact one’s sense of self. It also posits that people have inherent psychological needs for autonomy, competence, and relatedness. When these needs are satisfied, we are more likely to be driven by intrinsic motivation and thrive in the goal pursuit process, ultimately making decisions and engaging in self-directed behaviors that promote self-satisfaction, fulfillment, and enjoyment. In contrast, when these psychological needs are not sufficiently met, we might find ourselves in a state of amotivation (lack of motivation), or increasingly driven by extrinsic sources of motivation. This can result in a goal striving process that is characterized by a reduced sense of volition, enjoyment, and gratification. Even when goal-supporting tasks are being completed, it’s like crossing items off of a to-do list that was prepared for us (without our input), and we don’t cultivate the same feelings of mastery and fulfillment. The presently reviewed study (1) was a meta-analysis investigating the overall impact of coach autonomy support, which refers to “an assortment of coach or instructor-led behaviors that collectively yield a climate of support, care, and understanding within the sport setting.” The researchers sought to broadly 51 quantify the relationship between coach autonomy support and a wide range of psychological outcomes, in addition to exploring possible “moderators,” or additional variables that might impact the relationship between coach autonomy support and the outcomes of interest. In short, results generally indicated that coach autonomy support was positively associated with intrinsic motivation, satisfaction of basic psychological needs (autonomy, competence, and relatedness), well-being, and positive athlete functioning, and negatively associated with athlete distress and need frustration. These relationships were not significantly moderated by cultural group, type of sport, age, or competition level, which suggests that the findings may be generalizable to a broad variety of contexts. Psychology is important in endeavors related to fitness and athletics, but we only occasionally cover psychology papers in MASS. As a result, it’s possible that you’d like some clarification regarding the definitions of some of the terms used throughout this introduction section, and a little more context regarding how this theory relates to the typical fitness enthusiast or coach. Rest assured, the Interpretation section of this article will dig into the results of this study, with a deliberate focus on providing clear definitions of key terms and actionable examples for practical application. Purpose and Hypotheses Purpose The primary purpose of this meta-analysis was “to provide a basic overview of the [self-determination theory] research in this literature, providing broad descriptive evidence of various correlates and potential consequences of coach autonomy support, as well as their strength of association with important athlete outcomes.” The secondary purpose was “to examine possible moderators that could affect correlation magnitudes in this literature.” Hypotheses The researchers stated four hypotheses, which are directly quoted (with some elaboration removed in the interest of brevity) below: • “H1: Autonomy support will exhibit meta-analytic associations consistent with the internalization of motivation regulations in athlete motivation. That is, it should be most strongly and positively associated with motivations that are fully internalized and autonomous (i.e. intrinsic motivation), less related to external regulation, and negatively associated with amotivation. • H2: Autonomy support will exhibit main effect associations consistent with [self-determination theory] propositions: positive with basic needs, well-being, and negatively with ill-being and need frustration. • H3: Correlations with basic needs and internalized motivations will not vary as a function of the national culture of the study population. • H4: Correlations will be moderated by type of sport (e.g. team versus individual) with individual sports showing stronger associations.” 52 Methods Seasoned MASS readers are quite familiar with meta-analyses, but not quite in this exact format. We’ve covered numerous meta-analyses, which generally tend to follow the same format. The researchers identify a research question, such as “Does creatine increase maximal strength?” Then, the researchers gather up all of the comparable studies that investigate this question, while ensuring that they all conform to a set of pre-specified study criteria. Included studies will generally compare a creatine group to a comparator group (such as a control group or placebo group), and measure some continuous variable related to strength (such as bench press 1RM, squat 1RM, isokinetic peak torque, and so on). Due to the variety of different strength variables assessed, the researchers tend to convert all of these outcomes into standardized effect sizes (such as Cohen’s d or Hedges’ g). Finally, the researchers mathematically pool all of the individual study results together, and determine the overall (pooled) effect of, in this example, creatine supplementation on maximal strength. The presently reviewed paper took a similar approach in general, but aimed to quantify a very different type of effect size. This meta-analysis quantified correlations among participants within the included studies, rather than quantifying differences among groups within the included studies. Obviously the equations required for pooling correlation results are quite different from those required for pooling mean differences among groups, but the approach is statistically valid and the overall process of the meta-analysis is similar. These researchers searched the major electronic research databases for studies investigating the topic at hand, and included studies as long as they “investigated autonomy support in a sport or exercise setting distinct from physical education settings,” “measured self-rated, athlete-perceived or observer-rated autonomy support,” and “provided a correlation between autonomy supportive behavior and at least one relevant criterion variable (e.g., indices of athlete motivation or basic needs, well-being or distress, indicators of athlete functioning or climate, and other instructor or peer-related behaviors).” The initial search returned 13,780 studies. After screening and applying the exclusion criteria, this huge list was whittled down to 120. They further trimmed the list to avoid instances of duplicated results, leading to a final list of 119 studies, which included 131 samples and 38,844 total participants. With these studies, the researchers computed pooled correlations between coach autonomy support and a wide range of relevant outcomes, which generally fell into a few categories: 1) athlete motivation and basic needs, 2) athlete well-being, ill-being, and functioning, 3) sports climate and coach behaviors, and 4) athlete demographics. The correlations were presented in raw (uncorrected) form (Pearson’s r), and also presented as “true score correlations” (ρ), which are corrected to account for sampling and measurement error. The researchers also completed additional analyses to determine if results were meaningfully influenced by potentially impactful moderator variables, such as cultural group, type of sport, age, or competition level. 53 54 Findings Correlations between coach autonomy support and outcomes related to athlete motivation and basic needs are presented in Table 1. Correlations between coach autonomy support and athlete well-being, ill-being, and functioning are presented in Table 2. Correlations between coach autonomy support and sports climate, coach behaviors, and athlete demographics are presented in Table 3. It would be quite unpleasant to read through a wall of text detailing the results for each of the dozens of individual outcome variables contained within these tables, but fortunately the general findings can be summarized concisely. As the researchers put it: “Our meta-analysis confirmed positive associations with athlete basic need satisfaction, internal- ized motivation, well-being, positive athlete functioning, and negative associations with indicators of athlete distress and need frustration across cultures.” Even if you’re all about business and only interested in “the bottom line,” Table 2 shows that coach autonomy support was significantly associated with “performance and achievement” (ρ = 0.21, 95% confidence interval: [0.13, 0.30]). In addition, relationships did not appear to be substantially altered by the potential moderator variables investigated, which suggests that these correlations may be applicable and generalizable across a broad range of contexts. Interpretation The results of this study are fairly straightforward, and the limitations are similarly 55 straightforward. As a result, this Interpretation section will be heavily focused on understanding what self-determination theory is, how it applies to the typical fitness enthusiast (or coach), and how to actually put the theory into action. As I briefly mentioned in the Introduction section, self-determination theory assumes that people naturally have a curiosity to try new things, master new challenges, and to “integrate these experiences with a core sense of who they are” (2). Ideally, people operate with a strong sense of self-determined motivation, meaning that they are making volitional choices and taking volitional actions that are motivated by their own desires and ambitions, and they truly feel like they have some degree of control over dictating their own path forward. Self-determination theory was developed by Ryan and Deci (3), and it builds upon Maslow’s hierarchy of needs. Maslow proposed that humans have an inherent drive toward self-actualization, or becoming the best possible version of themselves (from their perspective). However, Maslow acknowledged that humans need to satisfy more basic, foundational needs (such as physiological needs and safety needs) before they can cultivate motivation to pursue higher-level goals related to self-actualization. Similarly, self-determination theory acknowledges that humans have an inherent drive toward self-improvement, but they will struggle to aggressively pursue this process when they lack the foundational conditions necessary. People are more likely to perceive a high level of self-determination in their choices and actions when they have a sense of relatedness, autonomy, and competence. However, when they are lacking one or more of these foundational elements, their sense of self-determination is impaired. Put concisely (2), relatedness refers to “being meaningfully connected with others,” autonomy refers to “feeling a sense of authentic choice in what one does,” and competence refers to “feeling effective in what one does.” Other authors define these terms with slightly different terminology (4), suggesting that relatedness refers to “the need to feel close to and understood by important others,” autonomy refers to “the need to feel choiceful and volitional, as the originator of one’s actions,” and competence refers to “the need to feel capable of achieving desired outcomes.” When these three needs are met, people tend to feel empowered to confidently and enthusiastically pursue growth opportunities, which are perceived as being very rewarding and fulfilling. Broadly speaking, motivation can be defined as “psychological energy directed at a particular goal.” However, an important aspect of self-determination theory is that it focuses on different types of motivation (5), with varying levels of quality among them. When insufficient relatedness, autonomy, or competence lead to a low sense of self-determination, it’s common to experience amotivation (a total lack of motivation). In this situation, a person might not feel competent enough to engage in goal striving behaviors, or might fail to see how a particular choice or behavior is valuable or relevant to their interests. Even if they are able to avoid a state of complete amotivation, they might instead find themselves relying heavily on extrinsic 56 motivation due to their low sense of self-determination. Self-determination theory lays out four different subtypes of extrinsic motivation (5), ranging from lowest quality (least internalized) to highest quality (most internalized), but intrinsic motivation is higher in quality than all forms of extrinsic motivation (4). When someone is acting due to extrinsic motivation, they might complete a task to get a reward from some authority figure, avoid ridicule or punishment from some authority figure, gain approval from peers, or avoid a sense of guilt. In contrast, someone acting due to intrinsic motivation is completing a task out of genuine interest, enjoyment, or the sense of satisfaction it brings. As Dr. Helms described in a previous MASS video, self-determination theory offers valuable insight for promoting sustainable intrinsic motivation. People feel more self-determined when their needs for relatedness, autonomy, and competence are sufficiently met. When people feel more self-determined, they tend to thrive, seeking to achieve goals that enhance their sense of self and enjoying the process along the way. They have a greater degree of intrinsic motivation, which leads them to complete goal-compatible behaviors with “greater effort, engagement, persistence, and stability” (4). In fact, when people are more self-determined, there is evidence to suggest that they perform better, display more creativity, and experience more happiness and satisfaction across contexts including marriage, academics, and weight loss programs (2). With this in mind, the presently reviewed findings are very straightforward and simple in nature, but with high potential for impact. The researchers assessed studies on coach autonomy support, which generally involves “taking steps to (a) provide choices to the athletes under one’s instruction, (b) provide athletes with a rationale for tasks and set limits, (c) acknowledge the athletes’ feelings and perspectives, (d) provide non-controlling, competence-based feedback, (e) aspire to prevent ego involvement, and (f) avoid overt controls, such as the use of tangible punishments or rewards to prompt desired behaviors” (1). As detailed in Tables 1, 2, and 3, autonomy support was positively associated with a huge list of positive psychological outcomes. It was positively correlated with the foundational components and the most important type of motivation involved in self-determination theory (relatedness, autonomy, competence, and intrinsic motivation), but also positively correlated with things like general well-being, positive affect, life satisfaction, self-esteem, performance and achievement, effort, and athlete-coach relationship quality. You might be surprised to see that coach autonomy support was associated with performance and achievement, but Dr. Helms previously reviewed some qualitative research suggesting that psychological attributes related to self-determination theory support success among world champions in a variety of sports. Coach autonomy support was also inversely associated with several unfavorable outcomes, such as thwarting and “need frustration” (absence of need satisfaction) of the foundational components of self-determination theory (relatedness, autonomy, and competence), negative affect, burnout, and amotivation. 57 Of course, we have to keep some noteworthy limitations in mind when interpreting these results. These studies are reporting observational correlations, so we can’t assume that coach autonomy support necessarily caused all of these positive outcomes. In addition, the researchers reported fairly substantial heterogeneity for a number of the reported outcomes. So, while results didn’t seem to substantially differ based on the moderator variables they tested (such as cultural group, type of sport, age, or competition level), there was still considerable variation in results among individual studies. Despite those limitations, the presently reviewed study provides some support for self-determination theory, while simultaneously suggesting that coaches have an opportunity to enhance their clients’ and athletes’ sense of relatedness, autonomy, and competence, while simultaneously promoting a long list of other positive psychological outcomes. This illustrates what is, in my mind, the most important point of this article: a good coach is not merely a spreadsheet generator. A coach’s job is to create and maintain a program that addresses the needs of the client, but also to cultivate an environment that enables the client to thrive. In this context, thriving refers not only to objectively successful goal attainment, but also to a positive subjective experience during the goal striving process. Coaches should aim to help their clients enjoy the process of achieving their goals, and to make the process a fulfilling and rewarding endeavor that contributes to personal growth and self-actualization. Now that we’ve established what self-determination theory is and A GOOD COACH IS NOT MERELY A SPREADSHEET GENERATOR. why it’s important, we can now discuss how to implement it in the context of a fitness program. Practical Application We can start promoting a client’s sense of self-determination before the first training session actually occurs. There is ample evidence (reviewed here) to suggest that establishing a robust and comprehensive goal hierarchy is a highly effective contributor to sustained client success. If you and your client approach goal setting in a collaborative manner, it opens up multiple opportunities to promote key elements of self-determination theory. The theory suggests that humans have a natural tendency to seek out self-improvement and self-actualization, and establishing a good superordinate goal at the top of the goal hierarchy can help a client see the clear connection between their goals, their values, and their ideal self (6). The mere act of collaborating on the goal setting process will foster a sense of relatedness, as this will ensure that you and your client are aligned and simultaneously pushing in the same direction together. Finally, as you begin filling in the details of intermediate and subordinate goals, there are an extremely wide range of options 58 to choose from. By seeking (and incorporating) feedback from your client and offering them genuine options to pick from, you can foster a heightened sense of autonomy. Collectively, this approach to goal setting should promote a great deal of intrinsic motivation for your client, which should be reasonably sustainable during the ups and downs of the subsequent goal striving process. there are multiple studies showing that incorporating even small opportunities for clients to make low-stakes choices can enhance performance. A client is most likely to thrive on a program when they share ownership of the decisions, they are being appropriately challenged, they believe the program is fully aligned with their goals, and they feel a sense of collaborative support from their coach. Similar methods can be applied during the program design process. When creating a program, it’s important that your client is asked to utilize skills and strategies that they are fairly comfortable with. A highly advanced program for a beginner client will directly threaten their sense of competence, and make the program far less enjoyable (and successful). Obviously, in the interest of self-actualization, your coaching will prompt the client to develop new skills and new proficiencies over time; as long as they are being challenged appropriately and you’re explaining how these challenges are conducive to their long-term success, you’ll be fostering a greater sense of intrinsic motivation. Just as with goal setting, it’s important to solicit feedback from your client during program design, and to actually incorporate that feedback to the extent possible. You can also build some autonomy-reinforcing opportunities into the program itself. For example, you can build in options for your client to determine when to take a diet break or a refeed, when to take a deload, how to distribute their total training volume throughout the week, which accessory lift to select, how many back-off sets to complete, or when to terminate a set. As Dr. Helms wrote back in Volume 1 of MASS, When providing corrective feedback to clients, we have another fantastic opportunity to support the foundational elements of self-determination theory. To support relatedness, all you need to do is show that you are truly listening to your client and trying to understand their perspective with empathy and compassion. As described by Mouratidis et al (7), we can also actively support autonomy when providing feedback. While some coaches might induce guilt or shame, verbally express disappointment, reactively withdraw support, or utilize threats of punishment, a coach aiming to support autonomy would “try to provide a desired amount of options and choice, coach from the players’ internal frame of reference, and give a meaningful rationale in case choice is constrained” (7). We can also promote a greater sense of competence when providing feedback, by actively providing some positive reinforcement and encouragement in combination with corrective feedback, and by carefully considering the skill level of the client when providing options for improving shortcomings or overcoming challenges. When we truly listen to a client, communicate areas requiring improvement while acknowledging areas of proficiency, provide some potential solutions that 59 are appropriate for their skill level, clearly explain the rationale behind these solutions, allow them to play a role in selecting their preferred option, and maintain a supportive style of communication throughout the process, we have seized an opportunity to cultivate an environment that fully supports the client’s well-being and promotes their longterm success. Obviously, these practical examples are written under the assumption that you are coaching someone else. However, you can still incorporate aspects of self-determination theory into the process of coaching yourself. A self-coached scenario implies a substantial degree of autonomy, but autonomy alone isn’t sufficient for promoting a high sense of self-determination. For example, freedom to make choices can lead to an unfavorable sense of self-doubt when you lack confidence in your ability to make the right choices and carry them out effectively. As a result, it’s important to pursue opportunities to boost your sense of competence. You might achieve this by attending courses or workshops to reinforce your practical skills, consuming more educational materials, or seeking out tools or equipment to facilitate your self-coaching process. You might also want to pursue opportunities to boost your sense of relatedness, as a completely independent fitness journey can potentially lead to an unfavorable sense of aimlessness or isolation. By doing something as simple as finding a training partner, regularly communicating with a peer or group of peers on a similar fitness journey, or joining a supportive online community with similar goals and interests, your self-coached process is no longer a completely isolating process, and you have a support network to boost your sense of relatedness. Next Steps While the correlations reported in this meta-analysis are intuitive and appear to be generalizable across many different contexts and scenarios, it’s important to recognize that these findings are observational in nature. As a result, it’s very hard to make causal inferences with this level of scientific evidence. In order to claim that greater coach autonomy support actually causes the favorable outcomes that it was correlated with in this meta-analysis, we’ll need well-controlled, longitudinal trials to build upon these findings. For example, it’d be really cool to see a longitudinal trial in which participants were randomly assigned to one of two coaching COACHES CAN IMPROVE THEIR CLIENT’S SUBJECTIVE EXPERIENCE, WELLBEING, AND INTRINSIC MOTIVATION, WHICH CAN ULTIMATELY PROVIDE A SOLID FOUNDATION FOR LONG-TERM SUCCESS. 60 APPLICATION AND TAKEAWAYS In the fitness world, coaches often spend a lot of time optimizing the quantitative components of the training and nutrition programs they prepare for clients, and rightfully so. Sets, reps, and loads are critically important, as are carbs, fats, and proteins. However, coaching involves a lot more than spreadsheet generation. The way your client experiences their program is important, and coaches influence the subjective experience of the client, whether that influence is intentional or unintentional. Coaches have an excellent opportunity to promote client autonomy by using simple strategies, such as inviting input, providing meaningful choices, explaining the rationale behind programming decisions, acknowledging the athlete’s feelings and experiences, and seeking to understand the athlete’s perspective. In doing so, there’s a high likelihood that coaches can improve their client’s subjective experience, well-being, and intrinsic motivation, which can ultimately provide a solid foundation for long-term success. approaches, which differ primarily (or, ideally, exclusively) by the degree to which they aim to provide autonomy support. Researchers could measure some of the outcomes explored in this meta-analysis to determine whether or not greater coach autonomy support actually causes some of the favorable outcomes that appear to be correlated with greater coach autonomy support. 61 References 1. Mossman LH, Slemp GR, Lewis KJ, Colla RH, O’Halloran P. Autonomy support in sport and exercise settings: a systematic review and meta-analysis. Int Rev Sport Exerc Psychol. 2022 Feb 2; ePub ahead of print. 2. Greenberg J, Schmader T, Arndt J, Landau M. Social Psychology: The Science of Everyday Life (1st ed). Macmillan Higher Education; 2015:221-223. 3. Ryan RM, Deci EL. Self-determination theory and the facilitation of intrinsic motivation, social development, and well-being. Am Psychol. 2000 Jan;55(1):68–78. 4. Patrick H, Williams GC. Self-determination theory: its application to health behavior and complementarity with motivational interviewing. Int J Behav Nutr Phys Act. 2012;9:18. 5. Ryan RM, Deci EL, Vansteenkiste M, Soenens B. Building a science of motivated persons: Self-determination theory’s empirical approach to human experience and the regulation of behavior. Motiv Sci. 2021;7(2):97–110. 6. Höchli B, Brügger A, Messner C. How Focusing on Superordinate Goals Motivates Broad, Long-Term Goal Pursuit: A Theoretical Perspective. Front Psychol. 2018 Oct 2;9:1879. 7. Mouratidis A, Lens W, Vansteenkiste M. How you provide corrective feedback makes a difference: the motivating role of communicating in an autonomy-supporting way. J Sport Exerc Psychol. 2010 Oct;32(5):619–37. █ 62 Study Reviewed: Activation Training Facilitates Gluteus Maximus Recruitment During WeightBearing Strengthening Exercises. Cannon et al. (2022) “Activation Training” May Increase Glute EMG BY GREG NUCKOLS A new study suggests that you can increase your glute activation during squats by doing some light glute “activation training” twice per day. This article will discuss some potential confounders in the study, and how confident we can be that glute activation training will actually improve muscle growth and strength gains. 63 KEY POINTS 1. Subjects performed glute “activation training” twice per day for a week. The training consisted of isometric clamshells, side-lying hip abduction, and fire hydrants. 2. Before and after the week of glute activation training, gluteus maximus EMG was assessed during bilateral and unilateral bodyweight squats. 3. During both bilateral and unilateral bodyweight squats, glute EMG increased by >50% on average. However, since these findings are very preliminary, we don’t yet know that glute activation training will definitely lead to greater muscle growth and strength gains. If you have trouble feeling a target muscle “firing” when lifting, a common recommendation is to give “activation training” a shot. In essence, you’re advised to find simple exercises that force the target muscle to carry the load, so that your nervous system can learn how to use the target muscle. This process is supposed to help you better activate the target muscle, so that you can utilize it more effectively during other exercises. While this recommendation sounds good in theory, I haven’t come across much evidence for its efficacy outside of a rehab setting. However, absence of evidence doesn’t necessarily imply evidence of absence. Fortunately, a recent study helps shed some light on the potential efficacy of “activation training.” In the present study (1), subjects completed one week of twice-daily activation training for their glutes. Before and after the training period, researchers assessed electrical activity in the subjects’ gluteus maximus during unilateral (single-legged) and bilateral (double-legged) bodyweight squats via electromyography (EMG), which provides a proxy measure for muscle activation (6). Following the week of glute activation training, glute EMG increased during bodyweight squatting variations by >50%, on average. So, is this definitive proof that “activation” training is effective? Read on to find out. Purpose and Hypotheses Purpose The purpose of this study was to investigate whether a one-week glute activation program can increase glute EMG during bodyweight bilateral and unilateral squats. Hypotheses The researchers hypothesized that glute EMG would increase following a one-week activation program. Subjects and Methods Subjects 12 subjects (5 females and 7 males) participated in this study. They were all physically active (exercising 3-4 days per week), but not actively engaged in resistance training. Of note, subjects were excluded if they had a 64 history of lower back and/or lower body pain, or a history of lower back or lower extremity injuries. Experimental Design This study employed a single cohort pre-post design. In other words, all subjects completed the same intervention, which means that we can see changes over time within the group, but there was no control group. Subjects completed two testing sessions, separated by seven days. The testing sessions began by assessing maximal isometric hip extension strength using a dynamometer. Following the hip extension strength assessment, subjects completed a submaximal reference voluntary contraction (RVC), to be used for subsequent EMG normalization (2). EMG electrodes were placed on the gluteus maximus, and the subjects completed five-second isometric hip extension contractions against a load equal to 75% of their maximal hip extension torque (for each subject, the same absolute load was used for both the pre-training and post-training reference voluntary contractions). Subjects were provided with a visual guide for the reference contraction to ensure they maintained the appropriate level of force output. For both the maximal and reference isometric contractions, subjects were positioned prone on the dynamometer with their hips hanging off the edge of the seat, and the pad positioned behind their knees. Their hips were in 30 degrees of flexion, and their knees were in 90 degrees of flexion. In essence, the subjects were in a position mimicking a bentknee reverse hyperextension. Following isometric testing, subjects were outfitted with reflective markers so that the researchers could assess joint kinematics using a camera system, and subjects completed three sets of three bilateral and unilateral bodyweight squats on a force plate. Bilateral squat stance was standardized (feet hip-width apart, with toes pointed forward), and unilateral squats were performed with the nonweight-bearing leg in 90 degrees of knee flexion. A metronome was used to standardize rep cadence for the bilateral squat (the eccentric and concentric were both 0.75 seconds), while subjects were allowed to perform the unilateral squat at a self-selected speed, so that they could more easily maintain balance. Glute EMG was assessed during both squat styles, and glute EMG values for each subject were normalized against the glute EMG values obtained during the reference isometric contractions. In the week between the two testing sessions, subjects completed twice-daily glute activation training. Each training season consisted of three exercises: side-lying clamshells, side-lying hip abduction, and quadruped fire hydrants. Subjects completed three one-minute isometric holds for each exercise (such that each activation session consisted of 9 total minutes of isometric holds). They were also provided with resistance bands to make the isometric holds more challenging; subjects started with the lightest band, and increased the band resistance as necessary. Subjects completed most of the activation training on their own, but at least four sessions were supervised by research assistants to ensure that the subjects were using proper technique. 65 Findings Hip joint kinetics and kinematics suggested that subjects’ squat technique didn’t meaningfully change after one week of glute activation training (Table 1). That’s a good thing, as it suggests that changes in glute EMG from pre- to post-training are reflective of “true” changes in glute EMG, rather than changes in glute EMG that may be reflective of changes in squat technique. Glute EMG during both bilateral and unilateral squats significantly increased from pre- to post-training (p < 0.01). For bilateral squats, glute EMG increased from 14 ± 6% RVC to 22 ± 11% RVC. For unilateral squats, glute EMG increased from 49 ± 21% RVC to 75 ± 34% RVC. In terms of individual subject data, 10 out of 12 subjects saw an increase in glute EMG during bilateral squats (with two subjects experiencing a decrease), and 9 out of 12 subjects saw an increase during unilateral squats (with one subject seeing a notable decrease, and two subjects experiencing no real change). Interpretation This article is a spiritual sequel to an article from Volume 4, which discussed a study in- 66 vestigating whether targeted accessory work could affect pec, triceps, and anterior deltoid activation (6) in the bench press (3). The study reviewed in that article found that targeted accessory work did seem to successfully increase EMG amplitudes for “lagging” muscles, but my discussion of the results pointed out several reasons why it may not be prudent to accept the results at face value. The present study shares one of the major drawbacks of the prior study (1). In both studies, it would likely be clear to the subjects that the purpose of the study had something to do with assessing muscle activation of the muscles being targeted by their assigned training intervention. If you show up to a lab, researchers put some electrodes on your butt, and then you’re told to do glute exercises twice per day for a week, you’re probably going to realize that the researchers are interested in assessing changes in glute EMG. With that in mind, it’s entirely possible that the post-training increases in glute EMG are IF YOU SHOW UP TO A LAB, RESEARCHERS PUT SOME ELECTRODES ON YOUR BUTT, AND THEN YOU’RE TOLD TO DO GLUTE EXERCISES TWICE PER DAY FOR A WEEK, YOU’RE PROBABLY GOING TO REALIZE THAT THE RESEARCHERS ARE INTERESTED IN ASSESSING CHANGES IN GLUTE EMG. 67 largely attributable to shifts in the subjects’ attentional focus. They may have simply been more cognizant of utilizing their glutes during their post-training squat assessments, resulting in an internal attentional focus on their glutes, thereby increasing glute EMG. It’s also possible that the changes partially reflect learning effects, which we can’t isolate due to the lack of a control group. Conversely, it’s also entirely possible that the observed increases in glute EMG in the present study are entirely attributable to the effects of one week of “activation training.” However, we don’t have a good way of disentangling these two potential explanations. With that said, I do think the results of the present study are a bit stronger than those of the prior study on bench pressing, for three primary reasons. First, in the prior study, subjects were assigned to groups based on the presence of muscle groups with “lagging” levels of activation, as identified during baseline testing. Thus, it’s possible that the results of that study were influenced by simple regression toward the mean – even if there were no “true” changes in muscle activation, you’d expect people with low pec EMG at baseline to record higher pec EMG values at post-testing, and people with high pec EMG at baseline to record lower pec EMG values at post-testing. Since all subjects in the present study underwent the same training intervention, and increases in glute EMG were observed in subjects with both low and high glute EMG amplitudes at baseline, it’s clear that the results of the present study weren’t driven by regression toward the mean. Second, the relative increases in glute EMG in the present study (53-57%) were simply much larger than the increases in pec (7.5%), triceps (20.5%), and front delt (12%) EMG observed during dynamic benching in the prior study. Changes in attentional focus can certainly impact muscle EMG, but the increases in the present study were large enough that they’re less likely to be explained solely by shifts in attentional focus. I think these results are more strongly suggestive of a “true” training effect. Third, the present study builds upon research that provides a clear mechanistic rationale for the observed effects. Back in 2016, the same research group found that a week of activation training could improve corticomotor excitability of the glutes (4). Thus, while the present study didn’t assess corticomotor excitability, it’s not unreasonable to assume that increases in corticomotor excitability help explain the observed increases in glute EMG, independent of potential shifts in attentional focus. So, how can we apply these findings? For starters, we certainly can’t claim that a week of activation training will definitely increase glute EMG during bodyweight squatting (it might for ~80% of people). We also can’t claim that increased glute EMG during bodyweight squatting will definitely translate to increased glute EMG when performing weighted lower body exercises (it very well might, but an overall increase in exertion may wash out the effect). We also can’t claim that increased glute EMG when performing weighted lower body exercises would definitely re- 68 sult in increased glute growth or an increased rate of strength gains (it very well might, but EMG hasn’t been validated as a predictor of longitudinal strength gains or hypertrophy; 5). So, with all of that in mind, the recommendations I’m about to give should be interpreted as super tentative recommendations. If you want to grow your glutes, if you feel like you struggle to fully integrate your glutes into compound lower body exercises, or if you feel like increased glute strength would pay dividends in exercises like squats and deadlifts, I don’t think it hurts to give daily “activation training” a shot. While more research is needed to know if glute activation training will truly aid in the pursuit of all of those goals, it doesn’t cost anything, the required time investment is pretty low, and the results of the present study are promising enough for me to think that daily glute activation training is at least worth experimenting with. I don’t know if the exercise protocol used in the present study (minute-long isometrics, twice per day) is the best possible glute activation training, but it certainly seems to work. If I were to give glute activation training a shot, I’d probably just do 30-40 bodyweight glute bridges a couple times per day (largely because I think I’d find the isometrics to be boring, and I personally feel clamshells and hip abduction exercises in my gluteus medius more than my gluteus maximus). It would be nice to be able to give glute activation training an unqualified endorsement, and to know the ideal daily glute activation protocol, but there are still a lot of unanswered questions. For now, though, I definitely don’t think it would hurt to give it a shot. I DON’T THINK IT HURTS TO GIVE DAILY “ACTIVATION TRAINING” A SHOT. Next Steps There are four follow-up studies I’d like to see. First, I’d like to see a replication of the present study, with the pre- and post-training assessments modified slightly. In both sessions, subjects should perform squats with both an internal attentional focus on squeezing their glutes, and an external attentional focus on squatting (well, jumping) explosively. This would negate my concern related to shifts in attentional focus potentially influencing the results. If glute EMG increased with both an internal and an external attentional focus from pre- to post-training, that would provide stronger evidence that “true” increases in glute activation (6) occurred. Second, I’d like to see an extension of the present study, using weighted exercises. It would be nice to see if glute EMG only increases when performing bodyweight exercises, or whether those increases still occur when performing squats and deadlifts with 70-85% of 1RM. 69 APPLICATION AND TAKEAWAYS 1. While longitudinal studies are needed to demonstrate that activation training can actually improve strength and hypertrophy outcomes, the present study suggests that activation training may actually increase activation of the target muscle during compound exercises. Thus, while I can’t yet give activation training a fullthroated endorsement, it’s certainly worth a shot if you feel like you struggle to integrate a particular lagging muscle into compound exercises. Third, I’d like to see a study comparing isometric and dynamic glute activation protocols. Do the increases in glute EMG occur only after isometric training, or would dynamic glute training lead to similar increases? Fourth, and most importantly, I’d love to see a longitudinal study on the subject. Two groups would complete the same training program, consisting of loaded deadlift and hip thrust training. One group would only perform the loaded barbell exercises, while the other group would perform a daily session of glute activation training. The study would compare strength gains and glute hypertrophy in both groups. If there were concerns that the activation training might directly and independently contribute to hypertrophy and strength gains (beyond potentially making the deadlifts and hip thrusts more effective), the group not performing activation training could perhaps do an extra set of deadlifts and hip thrusts in each workout to compensate. 70 References 1. Cannon J, Weithman BA, Powers CM. Activation training facilitates gluteus maximus recruitment during weight-bearing strengthening exercises. J Electromyogr Kinesiol. 2022 Feb 9;63:102643. doi: 10.1016/j.jelekin.2022.102643. Epub ahead of print. PMID: 35189569. 2. Besomi M, Hodges PW, Clancy EA, Van Dieën J, Hug F, Lowery M, Merletti R, Søgaard K, Wrigley T, Besier T, Carson RG, Disselhorst-Klug C, Enoka RM, Falla D, Farina D, Gandevia S, Holobar A, Kiernan MC, McGill K, Perreault E, Rothwell JC, Tucker K. Consensus for experimental design in electromyography (CEDE) project: Amplitude normalization matrix. J Electromyogr Kinesiol. 2020 Aug;53:102438. doi: 10.1016/j.jelekin.2020.102438. Epub 2020 Jun 10. PMID: 32569878. 3. Stronska K, Golas A, Wilk M, Zajac A, Maszczyk A, Stastny P. The effect of targeted resistance training on bench press performance and the alternation of prime mover muscle activation patterns. Sports Biomech. 2020 May 28:1-15. doi: 10.1080/14763141.2020.1752790. Epub ahead of print. PMID: 32460639. 4. Fisher BE, Southam AC, Kuo YL, Lee YY, Powers CM. Evidence of altered corticomotor excitability following targeted activation of gluteus maximus training in healthy individuals. Neuroreport. 2016 Apr 13;27(6):415-21. doi: 10.1097/ WNR.0000000000000556. PMID: 26981714. 5. Vigotsky AD, Halperin I, Trajano GS, Vieira TM. Longing for a Longitudinal Proxy: Acutely Measured Surface EMG Amplitude is not a Validated Predictor of Muscle Hypertrophy. Sports Med. 2022 Feb;52(2):193-199. doi: 10.1007/s40279-021-01619-2. Epub 2022 Jan 10. PMID: 35006527. 6. As a note, I’m using the term “activation” in this article because it’s the term used in the study, but excitation may be a better term, for reasons explained here. █ 71 Study Reviewed: Lean Mass Sparing in Resistance-Trained Athletes During Caloric Restriction: The Role of Resistance Training Volume. Roth et al. (2022) Should You Adjust Training Volume While Cutting? BY ERIC TREXLER How should you manipulate training volume while cutting? Due to a lack of direct research, it’s one of the most commonly debated questions in evidence-based fitness. A new systematic review adds fuel to the fire, but clarity still eludes us. 72 KEY POINTS 1. This systematic review sought to determine if differing levels of absolute training volume tend to correlate with better (or worse) lean mass changes among healthy, drug-free lifters consuming a hypocaloric (daily energy deficit ≥200kcal) and highprotein (daily protein intake ≥2.0g/kg of fat-free mass) diet. The researchers were also interested in evaluating relative changes in training volume (e.g., reducing or increasing volume from baseline). 2. The researchers concluded that actively reducing training volume during energy restriction may lead to greater losses of lean mass, whereas actively increasing training volume may lead to better lean mass retention. They also reported that highvolume programs were particularly effective for female lifters, who lost comparatively little lean mass. 3. Due to several confounding variables, I don’t believe this body of literature is suitable for answering the research questions at hand. Multiple perspectives are justifiable, but the question remains unanswered. Due to research on glycogen availability and detraining responses, I lean toward dropping volume a bit during particularly aggressive cutting phases, but the lack of direct research leaves plenty of room for individualization and differing perspectives. W eight loss phases (colloquially known as “cutting phases”) can get tough. Of course, there are the obvious challenges: hunger, lethargy, and food cravings are inherently unpleasant. However, fairly aggressive cutting phases (that is, cutting phases that implement a large daily energy deficit or result in very low body-fat levels) can lead to challenges in the gym as well. As cutting phases become increasingly aggressive, many lifters will tend to notice lower energy levels and impaired performance in the gym, along with hindered recovery from session to session. In light of these observations, many lifters cut some training volume in order to make their program more efficient, effective, and sustainable. This drop in volume might take the form of reducing accessory exercises, reducing set volume, or erring toward lower repetition ranges. But is this really an advisable strategy? You might be surprised to learn that we have shockingly little evidence to lean on when answering this question, and none of it addresses the topic in a truly direct manner. As Greg and I have previously discussed on our podcast (one, two), this question is frequently asked (and subsequently debated) in evidence-based fitness circles. However, we don’t have studies that actually compare longitudinal body composition changes in multiple groups undergoing experimental manipulations in training volume within the context of an intentional energy deficit. As a result, the presently reviewed paper (1) sought to address this question by leaning on indirect 73 research. They did a systematic literature search to gather studies investigating changes in lean mass among healthy, drug-free lifters consuming a hypocaloric (daily energy deficit ≥200kcal) and high-protein (daily protein intake ≥2.0g/kg of fat-free mass) diet for at least four weeks in duration, with the intention of determining if differing levels of training volume tend to correlate with better (or worse) lean mass changes. They were also interested in determining if relative changes in volume (that is, increasing or decreasing volume throughout a program) impacted lean mass changes. It would have been virtually impossible to justify pooling these data together for a formal meta-analysis, so the researchers instead opted to summarize the individual studies and evaluate the body of research in a qualitative manner, looking for general trends and patterns that might provide insight about the influence of training volume on lean mass changes during energy restriction. After reviewing the available literature, the researchers concluded that during energy restriction: 1) females on high-volume programs tended to retain more lean mass than males; 2) there was insufficient evidence to confidently conclude that high-volume programs spare more lean mass than low-volume programs (although the data seem to lean in that direction, particularly for female lifters); 3) actively reducing training volume may lead to greater losses of lean mass; and 4) actively increasing training volume may lead to better lean mass retention. However, they also cautioned that their “conclusions are based on correlational data, which pre- cludes the ability to draw strong causal inferences.” Aside from that caveat, I respectfully disagree with the premise that this body of research is suitable for answering the research questions at hand, and I believe there are several major confounding factors that are substantially influencing the researchers’ conclusions. As such, this article will discuss how the researchers’ conclusions came to be, which confounding variables might be driving those conclusions, and how other areas of research might point us toward entirely opposite conclusions. Purpose and Hypotheses Purpose The authors of this systematic review sought to investigate “whether higher training volumes are more appropriate for sparing lean mass during [caloric restriction].” While not directly stated as a purpose, they also sought to investigate the impact of relative changes 74 (from baseline) in training volume during energy restriction. Hypotheses As is common with systematic reviews, the researchers did not explicitly commit to a hypothesis. However, they highlighted the fact that resistance training volume “is a wellknown anabolic stimulus for muscle hypertrophy” in the introduction of the paper, and hinted at a rationale by which higher training volumes might be advantageous during caloric restriction. Methods I don’t think the researchers explicitly claimed the label of “systematic review” within this paper, but it was a systematic review nonetheless. The researchers conducted a systematic search of the literature, with the intention of aggregating all relevant studies published between 1990 and December of 2020. They were specifically looking for studies that evaluated the effects of various training volume levels on lean mass changes during caloric restriction in healthy, drug-free lifters. In order to be included in the review, studies needed to: “1) include lean, healthy, drug-free resistance-trained individuals, 2) last at least 4 weeks, 3) investigate hypocaloric conditions (≥200 kcal deficit/day), 4) report pre-post data for changes in lean mass, 5) employ a high-protein diet ≥2.0 g/kg [of fat-free mass], and 6) present information about [resistance training] variables used.” Unless I missed it, I don’t believe they provided specific criteria for how lean participants needed to be in order to satisfy these inclusion criteria. Notably, their inclusion criteria didn’t provide particularly specific requirements for how studies reported volume. The researchers stated that training volume “was preferentially expressed in total tonnage (number of repetitions × number of sets × intensity load; kg) or, when not applicable, in weekly sets/ muscle group. In the event that information regarding [resistance training] variables was missing, we quantified [resistance training] volume as sets/exercise.” As for categorizing training volumes as “high” or “low,” the researchers stated that “total sets per muscle group per week were categorized as follows: low (< 5), medium (5–9), or high (10 +).” The researchers would go on to categorize studies based on whether or not they used “progressive overload over time” or involved “reduced volume” (that is, a reduction in volume over the course of the program), but I couldn’t find any details about how these classifications were operationally defined. Based on the lax inclusion criteria and lack of clear definitions, there were multiple studies that “made the cut” to be included in the systematic review, but didn’t meet any of the classifications outlined – in other words, they weren’t categorized as high volume or low volume, they weren’t identified as using progressive overload, and they weren’t identified as using volume reductions over time. This presents a fairly substantial challenge for making inferences about training volume, as we’ll discuss later. After conducting the search and applying the inclusion and exclusion criteria, the researcher summarized the included studies by constructing a table containing information about study 75 methods, study duration, body composition changes, protein intake, resistance training program variables, and the estimated energy deficit. In conjunction with this summary table, the researchers also used a common scale (the PEDro scale) to assess the quality of each included study. This was not a meta-analysis, so the researchers did not attempt to formally pool the data from these studies to calculate an overall effect size. Rather, the researchers assessed the body of research in a qualitative manner, looking for general trends and patterns that might provide insight about the influence of training volume on lean mass changes during energy restriction. Findings The initial literature search yielded 2791 total studies. After screening these studies and applying exclusion criteria, the researchers ended up with a total of 15 studies, including 8 case studies. While case studies are not compatible with the PEDro scale, all other studies (except for one) were categorized as being “moderate quality” or higher. Absolute lean mass changes (from pre-testing to post-testing) in the included studies are presented in Figure 1. The researchers also provided a figure documenting the specific time course of lean mass changes (Figure 2). When interpreting figures 1 and 2, there are a couple of important things to keep in mind: 1) the results are divided by sex (female-only versus “other,” which includes all the male studies and a study by Campbell et al [2] with a mixed-sex sample); 2) the study by Stratton et al (3) was not included in these figures, as whole-body lean mass changes were not reported. In the absence of a quantitative meta-analysis, the “results” of this study consisted of a set of qualitative observations of trends and patterns in the literature, which were presented over the course of several paragraphs. In short, the researchers concluded that during energy restriction: 1) females on high-volume programs tend to retain more lean mass than males; 2) there is insufficient evidence to confidently conclude that high-volume programs spare 76 more lean mass than low-volume programs (although the data seem to lean in that direction, particularly for female lifters); 3) actively reducing training volume may lead to greater losses of lean mass; and 4) actively increasing training volume may lead to better lean mass retention. As a reminder, the researchers did not operationally define these categorizations (“reducing training volume” or “increasing training volume”) in quantifiable terms; it’s unclear if they’re specifically talking about changes in total volume load, changes in set volume, changes in repetition ranges, changes within a training block, or changes from the beginning to the end of a full program. To comprehensively assess the impact of relative changes in volume, you’d (ideally) want detailed information about how participants were training prior to study initiation, but this type of information was generally unavailable. As a result, it’s hard to conclusively determine which studies are actually observing a relative increase or decrease in training volume, relative to baseline. Interpretation There’s a common misconception that meta-analyses are “better” than systematic reviews, or that they provide a more robust level of evidence. In reality, that’s not always the case. A good meta-analysis will begin with a process that looks virtually identical to the systematic review process. However, after all of the studies are gathered and filtered according to the exclusion criteria, researchers who intend to conduct a meta-analysis have an important question to wrestle with: should we actually move forward with a quantitative THERE ARE FAR TOO MANY CONFOUNDING FACTORS WITHIN THIS BODY OF LITERATURE TO ATTRIBUTE DIFFERENCES IN LEAN MASS CHANGES TO DIFFERENCES IN TRAINING VOLUME. 77 statistical analysis? Sometimes, researchers will begin a project with the intention of conducting a meta-analysis, but will ultimately choose to do a systematic review (with no statistical analysis) instead. This is not a sign of failure or cutting corners, but rather a sign of prudent decision making and excellent discernment. There are many cases where it simply isn’t appropriate to mathematically combine a group of studies – due to the population studied, the study design, the details of the intervention, the outcomes measured, or any number of factors, the studies are simply too different from one another to lump them together and crunch the numbers. You might be wondering how this relates to the presently reviewed paper, given that there’s no indication that these researchers intended to conduct a meta-analysis in the first place. In my opinion, this paper finds itself in a scenario that is analogous to an intended meta-analysis with data that are simply too heterogeneous to combine. The presently reviewed paper sought to determine if alterations in training volume would meaningfully impact lean mass retention during energy restriction. Those types of inferences can only be made in a robust and generalizable manner if we believe that the included studies are generally similar in nature, except for quantifiable differences in resistance training volume from study to study. I respectfully reject that premise, and therefore place limited confidence in the conclusions proposed in the paper. In my opinion, there are far too many confounding factors within this body of literature to attribute differences in lean mass changes to differences in train- ing volume. These researchers spent an entire paper arguing their case, so a point-by-point rebuttal would require a document of similar length, which isn’t particularly feasible for an Interpretation section (or feasible for the busy readership of MASS). However, I believe I can concisely convey my perspective by identifying a few of the more glaring examples that highlight my skepticism. First, let’s take a look at the studies featuring male-only and mixed-sex samples in figures 1 and 2. The studies by Schoenfeld et al (4), Kistler et al (5), and Robinson et al (6) report substantial loss of lean mass (4+ kg). These are case studies on contest preparation in male physique athletes; considerable loss of lean mass is to be expected, as these athletes do everything in their power to optimize muscularity in the offseason, then undergo aggressive energy restriction to achieve an extremely lean physique. The Schoenfeld study is categorized as a high-volume study, and insufficient training volume information is provided by the Robinson and Kistler studies to allow for categorization. The only male contest prep study that fails to report considerable loss of lean mass is by Pardue et al (7), which is also categorized as a high-volume study, but that’s only true if you ignore the BodPod data. According to DEXA, the participant got to around 5.1% body-fat, but according to BodPod, they got to around 9.6% body-fat. If we assume that the “true” value is somewhere in-between (as a co-author of the paper, I believe this to be accurate), the lean mass losses look a lot more similar to the other case reports in this area. So, in the male studies, we’ve got four case reports; 78 two report insufficient volume information to be categorized, one high-volume study reported considerable lean mass losses, and another high-volume study reported large or small losses of lean mass, depending on which measurement you put more faith in. In summary, these case reports give us no indication that differences in training volume, or longitudinal changes in training volume, meaningfully alter lean mass retention. If we shift our focus to the other male studies in this systematic review, we see minimal lean mass losses reported by Campbell et al (2) and Dudgeon et al (8). This is fairly intuitive; while the case reports involved people with high baseline muscularity accomplishing large amounts of total weight loss in order to achieve extremely lean physiques, these other samples weren’t particularly huge or lean at baseline, they didn’t lose much weight, and they weren’t trying to get shredded. Even if we ignore those factors, the Campell study is categorized as utilizing progresive overload over time but also “reduced volume,” whereas the Dudgeon study is only categorized as utilizing progresive overload over time. At the surface level, this makes the effect of volume reduction seem equivocal, as both are treated as lean mass retention “success stories,” compared to the other studies including male participants. If we dig deeper than the surface level, we see that the Campbell study actually increased set volume over time; it looks like it was categorized as a “volume reduction” study because they included a deload halfway through the training program. While this is technically a transient volume reduction, it doesn’t really reflect the spirit of the research question; incorporating de- loads within a high-volume program is quite a bit different from intentionally reducing the overall volume of a program to accommodate the challenges of energy restriction. It’s also worth noting that participants could have utilized deloads in their usual training before the study, so this may or may not represent a “reduction” relative to baseline training habits. The lone example of the male studies that seems to directly support increasing (or at least maintaining) volume during a cut is the study by Mitchell et al (9). Participants had higher volume in the first 8 weeks than they did in weeks 9-16, and lean mass changes were more favorable in the first 8 weeks (+0.4kg) than the latter weeks (-0.9kg). However, there are several catches. This was an observational study in a small cohort of bodybuilders, so we would expect a greater threat for lean mass losses later in prep than earlier in prep, regardless of training specifics. It is known that some number of participants consumed high-calorie, high-carbohydrate refeeds prior to the 8-week midtesting, but there aren’t enough specifics to determine how that might have impacted the lean mass readings at that time point. It’s quite possible that some extra glycogen repletion and water weight could have inflated those lean mass values at week 8. In addition, the researchers did not control the training programs of participants; they merely calculated volume load (repetitions × sets × load) after the fact. As such, we can’t really conclude that an intentional decision to drop volume load led to lean mass losses. It’s equally possible that performance dropped a bit over the course of contest prep (it almost always does in male bodybuilders), and that 79 the observed drop in volume load represents an extremely common consequence of contest prep, rather than a strategic mistake causing the loss of lean mass. As a side note, these bodybuilders got to an average body-fat percentage of <7%, but lost only 4.1kg of total body mass during their entire contest prep. Given the context, this is a very modest magnitude of weight loss. They also lost only 0.5kg of lean mass from the start of prep to the end of prep. If you offered me that deal at the beginning of prep, I’d take it 10 times out of 10. Given all these caveats, it’s extremely hard to view the results of Mitchell et al as a cautionary tale about the perils of intentional volume reduction during energy restriction. We don’t know if the volume reductions were intentional or a simple consequence of performance impairment, if the time course of contest prep was a major confounding variable, and if the results for lean mass retention were actually excellent. In summary, the male-only and mixed-sample studies don’t really tell us much about the research question at hand. Unfortunately, we don’t get much from the female-only studies either. Only two samples documented losses of lean mass. One was the ketogenic diet group in a study (10) by Vargas-Molina et al (previously reviewed here), which was categorized as utilizing progresive overload over time but also incorporating volume reduction. As discussed many times in MASS (one, two, three), this small reduction in lean mass is consistently observed in keto studies (regardless of training volume), and may be related to the water weight loss associated with severe carbohydrate restriction. In addition, this was another instance where a study was categorized as a “volume reduction” study, despite the fact that volume progressively increased within each training block. Volume increased from week-to-week as participants transitioned through 1-week strength, hypertrophy, and muscular endurance microcycles, which culminated in a deload in week 4 of each training block. With this in mind, the studies by Vargas et al and Campbell et al are more relevant to research questions about incorporating deloads rather than strategically reducing the volume of your actual training sessions during a cut. The other female study reporting a loss of lean mass was by van der Ploeg et al (11). This was an observational study of five female bodybuilders during the 12 weeks prior to competition. There aren’t many details about their training programs, but they certainly don’t seem like low-volume programs – participants lifted for an average of nearly 6 hours per week, with the majority of sets in the 10-12 repetition range. This was categorized as a volume reduction study, but, once again, we have no clear indication that any of them were dropping volume as part of an intentional training strategy. The paper states that “None of the bodybuilders reported an increase in the volume of weight-training over the 12 [weeks], but four of them [out of five] stated that either the resistance or number of repetitions decreased as body mass was lost.” This could merely reflect the very common observation that your performance will likely drop throughout contest prep, and if you maintain the same general program structure, you’ll be unlikely to com- 80 plete the same number of repetitions with the same absolute training loads as prep continues. For example, it’s possible for absolute volume load (sets × reps × absolute load in kg) to decrease, even if you’re maintaining the same relative volume load (sets × reps × relative load in %1RM), purely due to performance decrements over time. A drop in absolute volume load could reflect an intentional decision to cut volume, but it could also reflect impaired performance on the exact same training program. It’s also worth noting that the competitors, on average, doubled their cardio volume during this time period, reaching nearly 10 hours per week of cardio. Another confounding variable favoring lean mass losses in this study pertains to the competitive category of the participants. They were competing in the “physique” division, and appear to have been striving for a different on-stage look than has been seen in similar case reports of female competitors. Based on DEXA values, these competitors began the observation period with nearly 56kg of fat-free mass, and finished prep at just under 10% body-fat. This combination of fat-free mass and leanness represents a look that falls more on the bodybuilding side of the competitive class spectrum than the bikini side, and would intuitively increase the likelihood of lean mass losses. You might push back on this assertion to some extent, given that head-to-head body composition comparisons are challenging when there are different measurement techniques involved, but it’s a factor worth considering. Overall, I don’t believe the empirical data included in the presently reviewed paper lend adequate support for the conclusions about differences between high-volume and low-volume approaches or longitudinal alterations in training volume. If we revisit the research question and purpose of the systematic review, I simply don’t think this body of research is well-suited for answering the question at hand. Weekly sets per muscle group were reported for three studies, and total volume load was available for only one study; for the other 11, training volume was quantified quite vaguely. In addition, “energy restriction” took many forms, ranging from recreational lifters losing a few pounds to experienced bodybuilders doing a full contest prep. On top of that, “volume reduction” did not specifically refer to the strategic reduction of training session volume to accommodate the unique challenges of energy restriction. Rather, it appears to have included things like incorporating deloads into a periodized training program, or experiencing very predictable performance decrements late in contest prep. However, that doesn’t mean I think the proposed conclusions are entirely indefensible. The researchers did a great job laying out the theoretical, mechanism-driven rationale by which maintenance of volume (or even increases in volume) might be favorable during energy restriction. They also provide some valuable insights about female lifters tending to retain lean mass more effectively than male lifters within these studies, and why that might be the case (although that’s probably a discussion for another day). However, I think there is a major disconnect between what these studies tell us and the question we’re 81 trying to answer. The authors were very transparent about the limitations of their paper and the tentative nature of their conclusions, so I am hopeful that people will practice caution when reading it, and won’t mistakenly assume that it provides a robust and definitive answer to this frequently debated question. sue if set volume per session is high enough. In other words, when a cut starts to get pretty aggressive, you might have to reduce training loads substantially if you insist on maintaining the exact same set and rep schemes, and your “borderline junk volume” can quickly become “absolute dumpster fire volume.” Sometimes we have to form tentative conclusions before strong scientific evidence is available. The topic at hand has not been directly studied, but, in the meantime, people are still doing fat loss phases and making decisions about training volume. While I welcome more direct research to provide some clarity, I personally lean toward keeping training variables pretty stable during conservative or moderate cutting phases, but sacrificing a bit of training volume (out of necessity) during more intense cutting phases, and my reasoning is two-fold. First, as discussed in a previous MASS article, even modest glycogen reduction has the potential to threaten high-volume resistance exercise performance. This might not be a huge deal when you’re in neutral or positive energy balance, or even if you’re doing a very conservative cut. However, if you’re cutting pretty aggressively (which generally involves a very large daily energy deficit or a very low body-fat level), glycogen repletion is a continuous uphill battle. Due to the persistent state of low energy availability, the limited carbohydrate you ingest is quickly and consistently put to use, such that it can be hard to make it to your workout with sufficient glycogen to fuel a tough workout full of high-repetition sets. Even with an approach that favors more lower-rep sets, glycogen can still become an is- If you trim some of your set volume and implement more higher-load, lower-rep sets, you can theoretically limit the degree to which glycogen depletion impacts training performance by shifting the bioenergetic burden of your workouts toward other energy systems that aren’t glycogen-dependent. By cutting volume in this manner, we have an opportunity to tailor the metabolic demands of our workouts to the relative capacities of our different energy systems, while reducing total training volume in a manner that accommodates our transiently reduced energy level and recovery capacity from session to session. Ultimately, the same stimuli that promote hypertrophy should generally promote lean mass retention during a cut. What changes is your recuperative capacity, since short-term (energy balance) and long-term (body fat) energy availability decrease as a cut progresses. It’s possible that my perspective on this topic is shaped by my tendency to err toward higher levels of volume during positive and neutral energy balance, as I think it’s valuable to explore the upper limits of your “ideal volume range” when conditions are ideal for muscle growth (that is, you have adequate energy availability and optimized recovery capacity). If you repeatedly observe that increasing volume dramatically offsets lean mass losses during a cut, this could pos- 82 SMALL AMOUNTS OF VOLUME SEEM TO GO A LONG WAY TOWARD PRESERVING LEAN MASS GAINS IN CONDITIONS THAT FAVOR MUSCLE ATROPHY. sibly suggest that you would have benefited from doing more volume in your gaining phase that preceded the cut. This whole glycogen rationale seems to imply that it’s okay to drop volume as long as intensity is maintained, and there’s some research to reinforce this idea. Bickel et al (12) studied how differing levels of volume reduction would impact the maintenance of training adaptations in cohorts of older and younger adults. After a 16-week lower-body resistance training program, participants spent the next 32 weeks doing one third of their initial training volume, one ninth of their initial training volume, or no training at all. As shown in Table 1, low-volume training was very effective at maintaining training-induced increases in lean mass, particularly in the younger cohort. Of course, there is a major limitation to acknowledge: the participants in this study were not on an energy-restricted diet. In addition, these were untrained subjects, who (by definition) aren’t challenged with the task of maintaining the high-level muscular adaptations seen in advanced lifters. As a result, it requires a leap of faith to apply these findings to the topic of volume fluctuations while cutting in well-trained lifters. Nonetheless, the results do suggest that even small amounts of volume seem to go a long way toward preserving lean mass gains in conditions that favor muscle atrophy. Personally, I am more 83 comfortable accepting these limitations when compared to the numerous confounding variables influencing the presently reviewed systematic review by Roth et al (1), but that’s admittedly a judgment call. Finally, there’s one more wrinkle to consider in this volume discussion. Even when we understand the typical effect of a particular training or nutrition strategy, we still have to be mindful of differences between individuals. An individual’s experience won’t always mirror the average group-level response observed in studies. Given that we don’t even have a firm understanding of the typical response to volume alterations during energy restriction, we should be even more open to tailoring approaches based on a given individual’s response. In the absence of an energy deficit, we know that there is considerable variation when determining the optimal amount of training volume to promote muscle hypertrophy (13). When you add energy restriction into the mix, things might get even more complicated. When cutting, it’s very possible that some lifters will find it particularly challenging to perform well and recover effectively on a high-volume program, while others might have a very different experience. With this in mind, it’s important to lean on past experience when determining if you should trim some volume during a cut. If you don’t have any experience to lean on, my inclination is to assume that most people will do a little bit better with some modest volume reductions during aggressive cutting phases. However, if you aren’t comfortable with this level of speculation, you could always include a mixture of high-volume and low-volume training sessions early in the cutting phase, and continuously monitor and compare performance and recovery responses to each type of session. As the cut progresses, you’ll quickly gain more clarity about whether you should be increasing, maintaining, or reducing your training volume. Next Steps This is probably the most obvious “Next Steps” section I’ve ever written – in short, somebody needs to do us a huge favor and actually investigate this research question. A nice approach would be to recruit a sample of participants and have them complete an 8-week familiarization phase, which would entail getting acclimated to a fairly standard high-volume, hypertrophy-focused training program in neutral energy balance. After this familiarization phase, participants would be randomly assigned to one of multiple groups; one group would maintain a similar amount of training volume, and another group would implement an intentional reduction of volume. Of course, we’d probably need multiple volume-reduction groups (or multiple studies) to determine if it’s particularly beneficial to drop volume by reducing repetition ranges or by trimming set volume (or neither). Throughout the duration of the training program, both groups would be in negative energy balance, with a daily energy deficit of around 250-500 kcal/day. Until this type of study is published and subsequently replicated, the debate about manipulating volume during aggressive weight loss phases will rage on. In the meantime, we’re left to lean on anecdote, theory, and indirect evidence, because it’s all we have. 84 APPLICATION AND TAKEAWAYS When it comes to the topic at hand, the only “wrong” answer is (in my opinion) an extremely confident one. At this point in time, we simply don’t have the applied, empirical evidence to confidently determine if lean mass retention is optimally promoted by high-volume or low-volume programs, or to determine if lean mass retention is optimally promoted by increasing, decreasing, or preserving volume, during periods of intensive energy restriction. In lieu of proper experimental evidence, we are left to form tentative conclusions based on anecdotal experience, mechanistic speculation, and indirect evidence. Based on evidence related to the effects of glycogen depletion on glycolytic exercise performance, and the effects of volume reduction on the maintenance of resistance training adaptations, I generally lean in favor of sacrificing volume to accommodate the unique demands of aggressive energy restriction. However, due to the glaring lack of direct evidence, this conclusion is extremely tentative in nature, and alternative conclusions are defensible. As such, this debate is sure to rage on until direct evidence becomes available. In the meantime, lifters and practitioners should lean on their experience and individualize their approach as needed; some lifters might struggle to perform well and recover from high-volume programs while cutting, whereas others might have entirely different experiences. 85 References 1. Roth C, Schoenfeld BJ, Behringer M. Lean mass sparing in resistance-trained athletes during caloric restriction: the role of resistance training volume. Eur J Appl Physiol. 2022 Feb 11; ePub ahead of print. 2. Campbell BI, Aguilar D, Colenso-Semple LM, Hartke K, Fleming AR, Fox CD, et al. Intermittent Energy Restriction Attenuates the Loss of Fat Free Mass in Resistance Trained Individuals. A Randomized Controlled Trial. J Funct Morphol Kinesiol. 2020 Mar;5(1):19. 3. Stratton MT, Tinsley GM, Alesi MG, Hester GM, Olmos AA, Serafini PR, et al. Four Weeks of Time-Restricted Feeding Combined with Resistance Training Does Not Differentially Influence Measures of Body Composition, Muscle Performance, Resting Energy Expenditure, and Blood Biomarkers. Nutrients. 2020 Apr 17;12(4):E1126. 4. Schoenfeld BJ, Alto A, Grgic J, Tinsley G, Haun CT, Campbell BI, et al. Alterations in Body Composition, Resting Metabolic Rate, Muscular Strength, and Eating Behavior in Response to Natural Bodybuilding Competition Preparation: A Case Study. J Strength Cond Res. 2020 Nov;34(11):3124–38. 5. Kistler BM, Fitschen PJ, Ranadive SM, Fernhall B, Wilund KR. Case study: Natural bodybuilding contest preparation. Int J Sport Nutr Exerc Metab. 2014 Dec;24(6):694– 700. 6. Robinson SL, Lambeth-Mansell A, Gillibrand G, Smith-Ryan A, Bannock L. A nutrition and conditioning intervention for natural bodybuilding contest preparation: case study. J Int Soc Sports Nutr. 2015;12:20. 7. Pardue A, Trexler ET, Sprod LK. Case Study: Unfavorable But Transient Physiological Changes During Contest Preparation in a Drug-Free Male Bodybuilder. Int J Sport Nutr Exerc Metab. 2017 Dec;27(6):550–9. 8. Dudgeon WD, Kelley EP, Scheett TP. Effect of Whey Protein in Conjunction With a Caloric-Restricted Diet and Resistance Training. J Strength Cond Res. 2017 May;31(5):1353–61. 9. Mitchell L, Slater G, Hackett D, Johnson N, O’connor H. Physiological implications of preparing for a natural male bodybuilding competition. Eur J Sport Sci. 2018 86 Jun;18(5):619–29. 10. Vargas-Molina S, Petro JL, Romance R, Kreider RB, Schoenfeld BJ, Bonilla DA, et al. Effects of a ketogenic diet on body composition and strength in trained women. J Int Soc Sports Nutr. 2020 Apr 10;17(1):19. 11. van der Ploeg GE, Brooks AG, Withers RT, Dollman J, Leaney F, Chatterton BE. Body composition changes in female bodybuilders during preparation for competition. Eur J Clin Nutr. 2001 Apr;55(4):268–77. 12. Bickel CS, Cross JM, Bamman MM. Exercise dosing to retain resistance training adaptations in young and older adults. Med Sci Sports Exerc. 2011 Jul;43(7):1177–87. 13. Scarpelli MC, Nóbrega SR, Santanielo N, Alvarez IF, Otoboni GB, Ugrinowitsch C, et al. Muscle Hypertrophy Response Is Affected by Previous Resistance Training Volume in Trained Individuals. J Strength Cond Res. 2020 Feb 27; ePub ahead of print. █ 87 Study Reviewed: The Effect of 3 vs. 5 Days of Training Cessation on Maximal Strength. Travis et al. (2022) Should You Take A Few Days Off to Peak Strength? BY MICHAEL C. ZOURDOS I’ve previously contended that tapering is overrated. However, I haven’t touched much on training cessation as a tapering strategy. Is training cessation the tapering strategy that you need to peak strength? A new study examined this concept. 88 KEY POINTS 1. Researchers had male and female powerlifters perform a strength-focused training block for four weeks. After four weeks, isometric force, body composition, and psychological scales were assessed, then subjects took either three or five days of complete rest before having outcome measures retested. 2. There were no significant differences between groups for any outcome measure from pre- to post-training cessation. There was a statistically significant decrease for isometric bench press force in the five day group, but the change was small (-2.38%). 3. Overall, this study showed that neither three nor five days of training cessation were beneficial for performance. The body of literature surrounding training cessation is underwhelming. At this point, I wouldn’t expect a large boost from a traditional taper or training cessation unless these strategies follow an overreaching phase, which causes substantial fatigue. I ’ve generally started MASS articles on tapering by whining that the concept is overrated. Then, I usually acknowledge that tapering is still good practice despite being overrated. Ultimately, these articles conclude with a statement indicating that maintaining load and decreasing volume are the tenets of tapering, and that tapering is most beneficial following a period of overreaching. However, an emerging strategy in the tapering research is training cessation, which Dr. Hayden Pritchard touched on in a MASS guest article. The presently reviewed study from Travis et al (1) had 19 lifters (16 men and 3 women) complete a four-week, powerlifting-specific (i.e., strength-focused) training block. Then, subjects took three days off of training (n = 9) or five days off of training (n = 10). Squat, bench press, and deadlift one-repetition maximum (1RM) were tested before and after the first four weeks of training. The researchers assessed isometric squat and bench strength, and various body com- position metrics, immediately after the four weeks (pre-training cessation) and immediately after training cessation. Strength increased during the four-week training block in both groups, with no between-group differences. Training cessation did not have any statistically significant effects on isometric squat strength; however, there was a statistically significant (p < 0.001) but small (-2.38%) decline in isometric bench press strength from before to after five days of training cessation. There were no significant differences between groups for body composition changes during the training cessation periods. However, the changes in various measurements such as skeletal muscle mass of the torso, right arm, and left arm had effect sizes favoring the three day group. Overall, these results suggest that lifters can maintain 1RM strength on the powerlifts following three days of training cessation, but upper body strength may slightly decrease after five days of complete rest. This article will aim to: 89 1. Review the present findings. 2. Place the present findings in context with the whole body of literature. 3. Examine if training cessation can increase strength or only maintain it. 4. Discuss the popularity of training cessation to peak strength among lifters. Purpose and Hypotheses Purpose The purpose of the reviewed study was to compare changes in strength, body composition, and psychological state following three and five days of training cessation after a preceding four-week powerlifting training block. Hypotheses No hypotheses were provided. Subjects and Methods Subjects 19 powerlifters (16 men and 3 women) participated in the present study. They were all well-trained and members of a University powerlifting club. Some lifters had competed in sanctioned powerlifting meets, while oth- ers had not yet competed. Subjects’ characteristics and baseline relative strength levels are in Table 1. Study Overview The presently reviewed study was a parallel-groups design with 19 powerlifters (16 men and 3 women) who were pair-matched by Wilks Score into two groups (five and three days of training cessation). For example, if two lifters with Wilks Scores of 435 volunteered for the study, one would have been placed in the three day group and the other in the five day group so that baseline Wilks Scores would be as similar as possible between groups. First, all 19 lifters performed the same four weeks of powerlifting-focused (low rep and high load) training for four weeks. Then they did not train for either three or five days. The researchers assessed squat, bench press, and deadlift strength pre-study and after four weeks (before training cessation). Isometric strength, body composition, and psychological scales were assessed pre-study, after four weeks (before training cessation), and after training cessation. Table 2 lists more specifics of all outcome measures. Training Program Table 3 shows the specifics of the training program. In brief, subjects trained three times 90 per week for the four-week block. They performed 1 to 5 reps per set with 80-100% of 1RM on the back squat, bench press, close grip bench press, and barbell row (days one and two) or the back squat, bench press, and deadlift (day three). Findings 1RM Strength Strength significantly increased (p < 0.05) during the four-week block for most measures and increased non-significantly for other measures (Table 4) with no group differences. Isometric Force During the four-week training block, iso- metric bench press strength statistically increased (p < 0.017); however, isometric squat strength did not significantly change (p > 0.05). During the training cessation period, isometric squat force did not significantly change (p > 0.05) in either group; however, isometric bench press force significantly decreased (p < 0.001; -2.38%) only in the five day training cessation period. Body Composition Body composition changes related to fat-free mass, fat mass, body mass, and skeletal muscle mass tended to increase over the fourweek block. Further, there were no significant within- or between-group differences for any body composition measure from pre- to 91 post-cessation. Importantly, Figure 1 shows the individual response for changes in fat mass and skeletal muscle mass, which were small and variable. Psychological Scales Most measures did not change throughout the study. The only change from before to after the cessation period was that muscle soreness decreased (p = 0.04). Overall, the psychological measures were uninteresting and did not significantly impact the findings; thus, we won’t harp on them. Statistical Criticisms and Musings Two minor points, and a third, which is a statistical note. First, I have previously reviewed a study from this research group. In that article, I said the following, which I would like to state here as well in the interest of full disclosure: “Although I believe I can provide an honest and objective analysis of this study, I feel it necessary to disclose my relationship with the authors. I am close friends with the senior author, Dr. Caleb Bazyler, who is also a previous guest contributor to MASS. Further, Dr. Bazyler, myself, and the lead author (Dr. Travis) have published a paper together. You can decide if this information is important, but I want to make sure I am disclosing anything that could be perceived as a potential conflict….In short, I know the authors well, and you can decide what to do with that information.” 92 Second, the previous study I reviewed from this research group was also a tapering study. In that article, I noted that outcome measures were assessed pre-study and again after the tapering period, but not immediately before and after the tapering period. I suggested that it would have been ideal for the researchers to also assess outcome measures immediately before the taper period to assess the true effects of the taper. Along with that suggestion, I noted that it would be difficult to test 1RM strength immediately before and after the taper period as 1RM tests within 1-2 weeks of each other would be time-consuming and fatiguing, but isometric tests would be feasible. In the current study, the researchers performed isometric tests at the beginning and end of the training cessation period, which was excellent. The presently reviewed study did not assess 1RM strength after the training cessation period, presumably due to the aforementioned time and fatigue considerations. I cannot fault the authors for that choice since that would have been admittedly difficult to do. However, it is worth pointing out that the decrease in isometric bench press force during the five days of training cessation does not necessarily indicate a decrease in dynamic bench press strength. As I noted in the last tapering review, since testing 1RM before and after the training cessation period would have been challenging, the authors could have used submaximal velocity to predict 1RM (video and downloadable calculator) before and after the cessation period. While this prediction does have a degree of error, it would have been feasible and straightforward. Third, although there were no significant changes in body composition measures from pre- to post-cessation, the authors did note moderate to large effect sizes in favor of the three-day group for changes in various measures. For example, the authors reported a 0.78 between-group effect size favoring the three-day group for skeletal muscle mass. Yet, the three-day group only increased skeletal muscle mass by 0.9% (33.1 ± 4.9kg to 33.4 ± 5.2kg), while the five-day group had a 1.1% decrease (35.2 ± 8.1kg to 34.8 ± 7.8kg). When using the equation [(mean three-day group change score – mean fiveday group change score) / pooled standard deviation of the pre-test mean], I get an effect size of 0.10. However, the authors calculated a Cohen’s dz value (then converted it to hedges g, which accounts for sample size). A Cohen’s dz uses a similar equation to the one above, except it divides by the pooled standard deviation of the change scores instead of the pre-test mean, inflating the effect size. Overall, it’s somewhat immaterial as the raw values are presented, and the changes from pre- to post-cessation are small. Nonetheless, if someone wanted to argue that the difference in skeletal muscle mass was meaningful, this could very well be explained by changes in total body water. In fact, total body water decreased by 1.4% from pre- to post-cessation in the five-day group but increased by 0.8% in the three-day group. Thus, any muscle mass changes favoring the three-day group may be explained by the decrease in body water. However, it should be stressed that the changes in skeletal muscle mass and total body water are small and unlikely to be meaningful. 93 Interpretation Technically, training cessation is a tapering strategy. As we’ve covered before, there are various tapering strategies, including step tapers and exponential tapers. As I already whined about, my general thoughts are that tapering is largely overrated. Tapering may yield a small (1-3%) benefit (2, 3), on average, but there should be a reason to taper (i.e., substantial fatigue is present). In other words, if someone is training with low volume, a taper may not be warranted. However, if someone is overreaching, tapering (i.e., decreasing volume and maintaining load lifted) is likely beneficial for maximal strength. Since we’ve covered tapering multiple times in the past, I want to focus this interpretation on the reviewed study’s strength findings, and the training cessation literature. The main take-home from Travis et al (1) is a slight decrease in isometric bench press performance after five days of training cessation. Otherwise, neither training cessation duration affected performance. Further, neither training cessation duration significantly affected skeletal muscle mass or fat mass, but muscle mass tended to be higher, and fat mass lower, following three days of cessation compared to five days. One could argue that strength and muscle mass can be maintained after three to five days of rest, but I don’t see much difference between the groups. First, there was no group × time interaction, and a significant decrease in isometric strength in the five day group is not equivalent to saying that strength decreased more than the three day group. Also, skeletal muscle mass did TAPERING MAY YIELD A SMALL (1-3%) BENEFIT (2, 3), ON AVERAGE, BUT THERE SHOULD BE A REASON TO TAPER (I.E., SUBSTANTIAL FATIGUE IS PRESENT). not statistically change in either group during the cessation period. Additionally, the individual changes (Figure 1) in both isometric strength and muscle mass tended to be small and variable. On the other hand, just because a statistically significant change in isometric bench press strength wasn’t observed after three days of training cessation doesn’t mean strength wasn’t decreasing. After three days of training cessation, there was a 0.94% decrease in isometric bench strength. While I normally wouldn’t even mention a 0.94% change in most outcome measures, it is only logical that strength will gradually decrease when you take time off. For example, if there were a 10 day training cessation group in this study, it would be surprising if strength was not lower after 10 days compared to five days of cessation. Ultimately, what’s most important to state is that the small nominal difference in strength changes between groups is 94 likely not biologically meaningful, and we do not know if these changes in isometric strength were indicative of changes in dynamic strength. Although the tapering literature has been historically endurance training-focused, more resistance training and tapering data have emerged in recent years. Similarly, there is a large body of training cessation literature, including a meta-analysis from Bosquet et al 2013 (4), focused on endurance and sport-specific outcomes. The meta-analysis included 24 studies that examined strength and power outcomes following a resistance training program. However, most of these studies were really detraining studies, in which subjects didn’t train for more than a week and, in some cases, over 200 days; thus, they are not applicable in the present context. The presently reviewed study makes it the fifth (1, 5, 6, 7, 8) to assess the efficacy of less than one week of resistance training cessation on maximal strength performance. All five studies are summarized in Table 5. Table 5 shows that the training cessation literature is underwhelming in both the number of well-designed studies and the positive results. For starters, the Anderson and Cat- 95 THE TRAINING CESSATION LITERATURE IS UNDERWHELMING IN BOTH THE NUMBER OF WELL-DESIGNED STUDIES AND THE POSITIVE RESULTS. tanach (8) study was only a conference abstract, while one of the Weiss studies (6) tested calf raise 1RM performance. This leaves us with the presently reviewed study from Travis et al (1), Pritchard et al (5), and Weiss et al (7). Most importantly, none of these three studies found that performance was significantly increased from pre- to post-cessation periods of two to seven days. One could argue that training cessation is worthwhile, as Pritchard showed percentage increases for all performance measures following both 3.5 and 5.5 day cessations, leaning in favor of 3.5 days. Weiss et al also showed nominal increases in 1RM bench press, but all effect sizes were trivial, and Travis et al observed performance to decrease. To further highlight these three studies, Table 6 shows the within-group percentage or effect size (whichever was available) changes in each study from pre- to post-cessation period. I think Table 6 further highlights the underwhelming nature of the training cessation literature. It’s possible that, similar to a conventional taper, training cessation is most effective following an overreaching phase. In other words, tapering is purported to be effective because it allows fatigue and soreness to dissipate (9). However, as I’ve written about before, the tapering literature is also underwhelming, and tapering is likely most effective following overreaching. None of the studies in Table 5 or 6 used an overreaching phase prior to training cessation; thus, it’s unlikely the lifters were fatigued enough to warrant 2-7 days of training cessation. In fact, I’d argue that, without the presence of an overreaching phase, taking five days off is more indicative of a detraining study. Hwang et al demonstrated that lifters mostly maintained maximal strength following two weeks of detraining (10 - MASS Review). However, the present study (1) shows a slight decrease in strength following five days of cessation. 96 Further, other tapering studies also show small decreases in measurements of hypertrophy after one to two weeks of significant volume reduction (11, 12, 13). Therefore, while it may take some time for a decrease in muscle performance to become statistically significant following training cessation or traditional tapering, it does seem that muscle performance tends to decline with five days of cessation. Despite a lack of evidence supporting a significant benefit of training cessation on maximal strength, lifters do tend to use some form of training cessation. Specifically, survey data have found that strongmen and strongwomen (14) tend to cease training ~4 days before competition, elite male and female New Zealand powerlifters (15) reported ceasing training ~4 days before a meet, and male and female Croatian powerlifters (16) ceased training ~3-4 days before competition. The survey data also reported that lifters performed their final heavy sessions 4-10 days before competition. Therefore, based on the training cessation literature, it doesn’t seem that strength athletes are using optimal tapering techniques (unless those athletes were overreaching). However, it’s important to reiterate that the tapering literature as a whole isn’t especially overwhelming either. To conclude, I won’t write an in-depth rehash of previous articles, but I will briefly restate that tapering is generally overrated, and it probably works best following an overreach. Since tapering won’t net a huge benefit, the first rule of “meet week” or “test week” should be to do no harm. To do no harm, I’d follow the general recommendations in Table 7. You can find specific examples here and here. Next Steps First, there need to be more studies looking at the effects of training cessation on freeweight barbell 1RM performance. So far, the only study to test free-weight 1RM immediately before and after a cessation period was Weiss et al (7). However, it is difficult to test a 1RM, and then test it again just a few days later, following a period of training cessation. Therefore, it’d be great to see a future training cessation study utilize submaximal velocity predictions of 1RM pre- and post-cessation. Additionally, taper training is most effective following an overreach; future studies should use an overreaching phase before training cessation. There are many different ways an overreach and training cessation study could go, since no studies on the topic currently exist. However, I’d start with a longitudinal study consisting of four groups. All groups would first perform the same six-week training block (or some other time frame), then the group protocols would be: 97 APPLICATION AND TAKEAWAYS 1. Travis et al (1) found that both three and five days of training cessation have little effect on muscle performance following a four-week powerlifting-focused training block. 2. Although there wasn’t a large effect on performance, it does seem that upper body maximal isometric force was trending downwards after five days of training cessation. 3. Ultimately, I’m skeptical that training cessation, or any traditional tapering strategy, will lead to a large boost in strength following a low volume training block. I’m of the opinion that tapering, of any kind, is best utilized following an overreaching phase that causes substantial fatigue. 1. A two-week overreach + three days of training cessation 2. A two-week overreach + five days of training cessation 3. A one-week overreach + one week step taper, then three days of training cessation 4. Two weeks of regular training followed by three days of training cessation The above design is not perfect, but we have to start somewhere. 98 References 1. Travis SK, Mujika I, Zwetsloot KA, Gentles JA, Stone MH, Bazyler CD. The Effects of 3 vs. 5 Days of Training Cessation on Maximal Strength. Journal of Strength and Conditioning Research. 2022 Mar 1;36(3):633-40. 2. Pyne DB, Mujika I, Reilly T. Peaking for optimal performance: Research limitations and future directions. Journal of sports sciences. 2009 Feb 1;27(3):195-202. 3. Pritchard HJ, Tod DA, Barnes MJ, Keogh JW, McGuigan MR. Tapering practices of New Zealand’s elite raw powerlifters. The Journal of Strength & Conditioning Research. 2016 Jul 1;30(7):1796-804. 4. Bosquet L, Berryman N, Dupuy O, Mekary S, Arvisais D, Bherer L, Mujika I. Effect of training cessation on muscular performance: A meta‐analysis. Scandinavian journal of medicine & science in sports. 2013 Jun;23(3):e140-9. 5. Pritchard HJ, Barnes MJ, Stewart RJC, Keogh JWL, and McGuigan MR. Short term training cessation as a method of tapering to improve maximal strength. Journal of Strength & Conditioning Research 32: 458-465, 2018. 6. Weiss LW, Coney HD, and Clark FC. Optimal post-training abstinence for maximal strength expression. Research in Sports Medicine 11: 145-155, 2003. 7. Weiss LW, Wood LE, Fry AC, Kreider RB, Relyea GE, Bullen DB, and Grindstaff PD. Strength/power augmentation subsequent to short-term training abstinence. Journal of Strength & Conditioning Research 18: 765-770, 2004. 8. Anderson T and Cattanach D. Effects of three different rest periods on expression of developed strength [abstract]. Journal of Strength & Conditioning Research 7: 185, 1993. 9. Pritchard H, Keogh J, Barnes M, McGuigan M. Effects and mechanisms of tapering in maximizing muscular strength. Strength & Conditioning Journal. 2015 Apr 1;37(2):72-83. 10. Hwang PS, Andre TL, McKinley-Barnard SK, Morales Marroquín FE, Gann JJ, Song JJ, Willoughby DS. Resistance training–induced elevations in muscular strength in trained men are maintained after 2 weeks of detraining and not differentially affected by whey protein supplementation. Journal of strength and conditioning research. 2017 Apr 1;31(4):869-81. 11. Bazyler CD, Mizuguchi S, Sole CJ, Suchomel TJ, Sato K, Kavanaugh AA, DeWeese BH, Stone MH. Jumping performance is preserved but not muscle thickness in collegiate volleyball players after a taper. The Journal of Strength & Conditioning Research. 2018 Apr 1;32(4):1020-8. 99 12. Suarez DG, Mizuguchi S, Hornsby WG, Cunanan AJ, Marsh DJ, Stone MH. Phasespecific changes in rate of force development and muscle morphology throughout a block periodized training cycle in weightlifters. Sports. 2019 Jun;7(6):129. 13. Travis SK, Mizuguchi S, Stone MH, Sands WA, Bazyler CD. Preparing for a national weightlifting championship: A case series. The Journal of Strength & Conditioning Research. 2020 Jul 1;34(7):1842-50. 14. Winwood PW, Dudson MK, Wilson D, Mclaren-Harrison JK, Redjkins V, Pritchard HJ, Keogh JW. Tapering practices of strongman athletes. The Journal of Strength & Conditioning Research. 2018 May 1;32(5):1181-96. 15. Pritchard HJ, Tod DA, Barnes MJ, Keogh JW, McGuigan MR. Tapering practices of New Zealand’s elite raw powerlifters. Journal of strength and conditioning research. 2016 Jul 1;30(7):1796-804. 16. Grgic J, Mikulic P. Tapering practices of Croatian open-class powerlifting champions. The Journal of Strength & Conditioning Research. 2017 Sep 1;31(9):2371-8. █ 100 Research Briefs BY ERIC TREXLER In the Research Briefs section, Eric Trexler shares quick summaries of recent studies. Briefs are short and sweet, skimmable, and focused on the need-to-know information from each study. 102 107 Is the 5:2 Diet a Viable Option for Lifters? Continuous Glucose Monitors: What Are They Good For? 113 Understanding the Risks That Accompany the Rewards for Female Physique Athletes 119 Comparing the Effects of Morning Versus Evening Workouts on Total Daily Energy Expenditure 101 Study Reviewed: Intermittent Fasting and Continuous Energy Restriction Result in Similar Changes in Body Composition and Muscle Strength When Combined With a 12 Week Resistance Training Program. Keenan et al. (2022) Is the 5:2 Diet a Viable Option for Lifters? BY ERIC TREXLER “Intermittent fasting” is an umbrella term. In the evidence-based fitness world, we often think of intermittent fasting as time-restricted feeding, which involves implementing a daily fasting period (typically between 16-23 hours long), but allows for daily energy consumption within the specified feeding window. However, many other strategies can be considered forms of intermittent fasting (2). For example, there is alternate-day fasting, in which dieters alternate between normal eating days and complete fasting days (that is, virtually zero energy intake for the full 24-hour period). There’s also modified alternate-day fasting, which alternates between normal eating days and very, very low-calorie days (typically ≤40% of an individual’s maintenance calories, or ≤600 kcal/day). Another option is the “5:2 diet.” This consists of five normal eating days per week, along with two “fasting” days. These fasting days can be consecutive or nonconsecutive, and typically allow for ≤40% of an individual’s maintenance calories, or ≤600 kcal/day. We’ve covered time-restricted feeding many times in MASS (one, two, three), but I’m not aware of any studies investigating the 5:2 diet within the context of resistance training. Until now, that is. The presently reviewed study by Keenan et al (1) sought to compare the effects of 5:2 intermittent fasting and regular, continuous energy restriction on changes in strength and body composition over 12 weeks. This study was completed by 17 weight-stable, healthy, untrained adults between 18-45 years of age (8-9 males and 8-9 females in each group). In order to participate, males needed to have a body-fat percentage above 18%, and females needed to have a body-fat percentage above 25%, as measured via DXA. Training consisted of two supervised full-body resistance training sessions per week, in addition to one unsupervised training session that consisted of bodyweight calisthenics. The continuous diet group consumed a daily energy deficit of around 20% (that is, they consumed 80% of their estimated energy needs), while aiming for a daily protein intake of about 1.4g/kg. The 5:2 group consumed 100% of their estimated energy needs five days per week, and implemented 102 two modified, nonconsecutive fasting days per week (on non-training days). I call them “modified” fasting days because they allowed for some energy consumption, rather than requiring a complete absence of energy intake. On these fasting days, participants were instructed to consume only 30% of their energy needs (e.g., a 70% deficit), and to consume all of their calories between noon and 6pm. The 5:2 group was instructed to consume 1.5g/kg of protein on non-fasting days, and 1.1-1.2g/ kg on fasting days. As a result, the diets were approximately isocaloric and isonitrogenous, with both groups averaging a 20% energy deficit across the week and consuming an average of about 1.4g/kg/day of protein. In short, the performance results in this study weren’t particularly exciting or informative. Strength and strength-endurance were assessed by determining bench press and leg press 3RM values, in addition to total volume completed (load × reps) during a single set to failure with 70% of the individual’s estimated 1RM load for bench press and leg press. The performance results weren’t particularly exciting, because there were no significant interaction effects to speak of; these untrained participants generally got stronger in response to 12 weeks of training, and the males generally lifted greater loads than the females. Beyond that, the performance results were, in my opinion, bound to be fairly uninformative anyway. When untrained individuals complete 12 weeks of resistance training, their initial strength gains will be very large and driven primarily by factors related to motor learning and skill acquisition. In this context, you’re unlikely to observe a statis- tically significant effect of a nutrition intervention on strength outcomes, even in a very well-controlled study. In addition, participants in the presently reviewed study didn’t actually train the leg press or bench press exercises throughout the 12-week training program. This makes us even less likely to observe a statistically significant effect, given that we’re looking at residual adaptations that are carrying over to the bench press and leg press tests from entirely different training exercises. As a result, that’s just about all I’m going to say about the performance outcomes from this study. As we move to body composition results, things start to get more interesting. You might have noticed that the beginning of this study’s title gives away the ending: “Intermittent fasting and continuous energy restriction result in similar changes in body composition.” That statement isn’t untrue, but it tells only a portion of the whole story, and from a lifter’s perspective, it tells the least informative part (in my opinion). As that title suggests, DXA results indicated that participants increased lean mass while losing weight and fat mass, with no significant differences between the groups. However, in addition to measuring whole-body lean mass via DXA, the researchers also measured changes in muscle size via ultrasound and CT (computed tomography) scans. These more direct measures suggested that the continuous energy restriction diet led to significantly larger increases in muscle surface area, and led to more favorable changes in ultrasound measurements of muscle cross-sectional area and thickness, with two of the three ultrasound outcomes reporting p-values near 103 the statistical significance threshold (p = 0.05 and p = 0.07). A selection of body composition and muscle size outcomes are presented in Table 1. When reviewing research, we always have to keep important limitations in mind. When it comes to hypertrophy studies, there are two glaring and fairly ubiquitous limitations that we encounter frequently: limited muscle growth can occur over a timespan of only 8-12 weeks, and most common measurement techniques for muscle hypertrophy lack precision. As a result, it would be very shortsighted to confidently conclude that two dietary approaches are “equivalent,” just because changes in whole-body lean mass, measured via DXA, were not significantly different between groups. As a side note, this would also be incorrect, as we cannot say that things are “equivalent” just because they aren’t significantly different; you can find more information about this distinction here and here. The first implication of these limitations is that, whenever possible, we should place more confidence in more direct measures of hypertrophy than less direct measures of hypertrophy. In some of my recent work on protein sources, I’ve cautioned that blood amino 104 acid responses are not perfect proxies for muscle protein synthesis, and that muscle protein synthesis is not a perfect proxy for changes in lean mass. We can take that one step further by acknowledging that the change in wholebody lean mass is not a perfect proxy for muscle hypertrophy. Lean mass changes derived from DXA (and other common body composition techniques) are informative, but they refer to all non-fat tissues of the body rather than muscle tissue specifically. When compared to direct measures of hypertrophy (such as changes in volume or area, as measured via ultrasound, MRI, CT scan, or muscle tissue biopsies), these whole-body measures of lean mass are less ideal because they are influenced by non-muscle lean tissues, and they are less able to provide a precise quantification of changes in muscle size. In a study like this, where the DXA-derived lean mass values suggest no significant difference, but the more direct measures (ultrasound and CT scan) lean toward a less favorable change in the 5:2 diet group, I’m inclined to place more confidence in the ultrasound and CT scan results. It might seem that I’m placing too much confidence in these results, given that only one of the ultrasound and CT scan outcomes in Table 1 actually cleared the bar for statistical significance. That’s a defensible perspective, but there are some scenarios in which “almost significant” findings warrant some extra attention. In this case, the CT and ultrasound results all generally lean in the same direction, and we’re talking about hypertrophy measurements over a short 12week time frame. As we recently saw in a review by Dr. Helms, it’s very possible that we only get subtle clues about unfavorable hypertrophy responses in short-term studies (3) on intermittent fasting strategies (such as time-restricted feeding), which start to materialize into larger and more noteworthy discrepancies over longer periods of time (4). In addition, the 5:2 diet intervention in this study was structured in a way that defies our current understanding regarding “best practices” of total daily protein intake and protein distribution. The fasting days utilized a protein target (1.1-1.2g/kg) that is well below the standard “optimal” range of 1.6-2.2g/ kg (5), and the meal distribution guidelines constrained the feeding window in a manner that would reduce the likelihood of getting at least three large protein doses spread throughout the day, which seems to be favorable (6). So, we’ve got a short study timeline, some “almost significant” results leaning in the same direction, and they’re leaning in a direction that makes perfect sense based on our current understanding of protein intake and distribution. In this type of scenario, I’m inclined to pay a little more attention to the ultrasound and CT scan results, even if there aren’t statistically significant findings across the board. In conclusion, these findings make it hard to suggest that the 5:2 diet is an “optimal” approach for lifters. However, it’s also worth noting that this dietary strategy did not have an absolutely catastrophic impact on various indices of hypertrophy. Collectively, the data suggest that continuous energy restriction led to more favorable changes in muscle size, but the 5:2 approach might still have some utility if your top priority is fat loss, you’re 105 comfortable with a slightly suboptimal effect on muscle mass, and it’s the energy restriction method that most effectively suits your preferences and reinforces your consistency. Weight loss can be extremely challenging, and the method that most effectively supports your consistent adherence may not necessarily be the approach that is fully optimized for skeletal muscle growth or retention. If you do find the 5:2 approach to be an attractive option, I suspect you can minimize some of the downsides by following a few simple guidelines for your fasting days: make sure they’re scheduled on non-training days, try to aim for a protein target of (at least) 1.4-1.6g/kg, and try to get at least 3 large protein feedings, distributed fairly evenly throughout a feeding window of at least 8 hours in duration. This approach still might not lead to a totally optimal situation for muscle growth (or maintenance), but it’s probably the best way to structure the 5:2 diet for lifters. References 1. Keenan SJ, Cooke MB, Hassan EB, Chen WS, Sullivan J, Wu SX, et al. Intermittent fasting and continuous energy restriction result in similar changes in body composition and muscle strength when combined with a 12 week resistance training program. Eur J Nutr. 2022 Jan 27; ePub ahead of print. 3. Moro T, Tinsley G, Bianco A, Marcolin G, Pacelli QF, Battaglia G, et al. Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males. J Transl Med. 2016 13;14(1):290. 4. Moro T, Tinsley G, Pacelli FQ, Marcolin G, Bianco A, Paoli A. Twelve Months of Time-restricted Eating and Resistance Training Improves Inflammatory Markers and Cardiometabolic Risk Factors. Med Sci Sports Exerc. 2021 Dec 1;53(12):2577–85. 5. Morton RW, Murphy KT, McKellar SR, Schoenfeld BJ, Henselmans M, Helms E, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance traininginduced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018 Mar;52(6):376–84. 6. Yasuda J, Tomita T, Arimitsu T, Fujita S. Evenly Distributed Protein Intake over 3 Meals Augments Resistance Exercise-Induced Muscle Hypertrophy in Healthy Young Men. J Nutr. 2020 Jul 1;150(7):1845-1851. 2. Patikorn C, Roubal K, Veettil SK, Chandran V, Pham T, Lee YY, et al. Intermittent Fasting and Obesity-Related Health Outcomes: An Umbrella Review of Meta-analyses of Randomized Clinical Trials. JAMA Netw Open. 2021 Dec 1;4(12):e2139558. 106 Study Reviewed: Validity of Continuous Glucose Monitoring for Categorizing Glycemic Responses to Diet: Implications for Use in Personalized Nutrition. Merino et al. (2022) Continuous Glucose Monitors: What Are They Good For? BY ERIC TREXLER Diabetes is a serious medical condition requiring ongoing management. In Type 1 diabetes, which accounts for less than 10% of diabetes cases in the United States (2), an autoimmune attack damages the beta cells of the pancreas, which are responsible for producing and secreting insulin when blood glucose rises. As the beta cell population becomes depleted, an individual with type 1 diabetes begins to display symptoms of insulin deficiency and impaired blood glucose regulation, which is rectified by the use of exogenous insulin. In people who are progressing toward type 2 diabetes, peripheral cells outside of the pancreas can become less responsive to insulin over time, largely influenced by factors including genetic predisposition, lack of physical activity, aging, and excess adiposity. At first, the problem isn’t particularly severe; peripheral cells become less responsive to insulin, but our pancreatic beta cells can simply produce more insulin to induce the intended cellular response. This is known as insulin resistance, which can be characterized by high blood insulin levels, but fairly normal blood glucose levels. However, if the condition progresses, the body may become less able to effectively regulate blood glucose levels over time, leading to chronic hyperglycemia (high blood sugar) and a progressive impairment of beta cell function (2). As insulin resistance progresses into advanced type 2 diabetes, we increasingly see higher blood glucose levels and lower blood insulin levels, which indicate impaired glycemic control and progressive damage to beta cells. When you have diabetes, careful management of blood glucose levels is critically important. Acute hypoglycemic episodes (low blood glucose) can induce confusion, fainting, seizures, comas, and even death (if severe and untreated). In addition, it may adversely affect brain development in children, and may cause strokes or heart attacks in older adults. On the other end of the spectrum, chronic hyperglycemia can promote progressive beta cell deterioration, atherosclerosis, cardiovascular disease, stroke, retinopathy (eye issues), nephropathy (kidney issues), and neuropathy (nerve issues). Clearly, the stakes for effective blood glucose management are high. 107 People with diabetes can use many tools and assessments to monitor their blood glucose regulation. For example, they may use fasted blood glucose tests, blood tests that assess their blood glucose response to a standardized meal, or blood HbA1c tests, which give a decent assessment of average blood glucose levels over the preceding 2-3 months. Another option is to use a continuous glucose monitor, which involves implanting a sensor under your skin (usually on your arm or abdomen), which continuously monitors glucose levels in your interstitial fluid (the fluid found between cells). This makes all the sense in the world for diabetes management, but you might be surprised to hear that fitness enthusiasts are increasingly using continuous glucose monitors, in hopes that they’ll provide actionable feedback for ultra-personalized nutrition strategies. Of course, in order to enable such nutrition strategies, the devices have to give glucose feedback that is both valid (accurate) and reliable (consistent). The presently reviewed study by Merino et al (1) was very straightforward: the researchers analyzed data from a large study to assess the repeatability of continuous glucose monitor readings by looking at the level of within-device agreement (for the the Abbott Freestyle Libre Pro), and looking at the level of agreement between two different devices (the Abbott Freestyle Libre Pro and the Dexcom G6). In order to assess within-device agreement, 360 participants wore an Abbott Freestyle device on each arm. In order to assess between-device agreement, 34 participants wore the Abbott device on one arm, and the Dexcom device on the other. The available data documented blood glucose readings for 394 healthy participants, who utilized both devices over the span of 14 days in a free-living setting. Over the course of 14 days, they consumed a total of 4,457 standardized meals and 5,738 ad libitum meals. In short, this study reported pretty solid within-device repeatability, although the agreement between devices wasn’t quite as great. For example, when looking at the coefficient of variation for 2-hour glucose area-under-curve values after standardized meals, it was 3.7% within-devices and 12.5% between-devices. In the context of ad libitum meals, values increased to 4.1% within-devices and 16.6% between-devices. Figure 1 presents the agreement between measurements from the same device model (A) and measurements from two different device models (B), along with coefficient of variation statistics (C). If it sounds like the science is settled and we should all be ordering some continuous glucose monitors, it’s not quite that simple. First, there are somewhat contradictory findings to consider; while the presently reviewed study reported pretty good agreement, that’s not the unanimous consensus within the literature. Howard et al (3) reported repeatability statistics that were considerably less impressive. For example, both papers compared within-subject meal rankings (in terms of glucose responses) using the different devices. While the presently reviewed paper reported a high degree of between-device agreement (tau = 0.68), Howard et al reported considerably poorer agreement (tau = 0.43). Howard et al also reported a significant bias by which one 108 device provided higher glucose readings than the other, but the magnitude of this bias was significantly impacted by body-fat, such that discrepancies for leaner individuals were different than those for individuals with higher body-fat levels. For a visual representation of the poor agreement reported by Howard et al, Figure 2 shows how the two devices simultaneously reported very different glucose responses to the same exact meals, eaten by the same participant. Discrepancies between the results of Howard et al and the presently reviewed study could be caused by several factors. For instance, 109 Howard et al followed the placement recommendations provided by the device manufacturers, whereas the presently reviewed study standardized monitor placement in a manner that defied the Dexcom manufacturer instructions. While both compared an Abbott device to a Dexcom device, the specific models were different. As such, it’s possible that the newer device models used in the presently reviewed study simply perform substantially better than the older models from each company. However, even if we run with that justification, and trust that the newer models perform better, all that tells us is that these devices might help people monitor their blood glucose levels. That’s a far cry from justifying any claims about facilitating health or performance in individuals without diabetes. I’m not fond of leaning too hard on anecdotes, but they provide great insight about the subjective experience of a particular intervention, and this particular conversation (continuous glucose monitors for health and performance in people without diabetes) is completely bereft of our scientific fundamentals in the first place. Unless I’m missing something, the purported benefits seem to be hypothetical and asserted without evidence, which means you’d be well within your “scientific rights” to reject them without evidence. However, this article from Men’s Health managed to highlight just about all of my practical concerns about continuous glucose monitors. The article contains a lot of catastrophizing about normal daily fluctuations in blood glucose, which appears to be causing unwarranted distress (“Watching my glucose level rise and fall through the day told a different, and more alarming, story than the static reading at my doctor’s office”) and orthorexic tendencies (“My [continuous glucose monitor] seemed to be okay with things like eggs and bacon in the morning, steak or grilled salmon at dinner, salads and leafy vegetables, nuts instead of chips at snack time, and pretty much anything involving avocados”). It also led to a very predictable trend in which the devices seemed to blatantly penalize carbohydrate consumption, nudging people toward lower and lower carbohydrate intakes (“I’ve always loved carbs and have never been a fan of any kind of labeled diet, but my CGM was carb-shaming me”). If the goal is just to keep glycemic control within standard, non-diabetic ranges, then there’s no need for a continuous monitor. If, however, you use a monitor and phone app to “gamify” stability of blood glucose responses, then a ketogenic diet is a cheat code to win the game. I guess that’s fine, as low-carb and ketogenic diets are a viable dietary option, but it’s hard to frame a device as promoting hyper-individualized diet optimization for health and performance if all roads lead to carb restriction; that is explicitly not individualized, and that doesn’t jive with the evidence on high-intensity exercise performance (4) or mortality (5). In addition, the same meal eaten on multiple occasions led to very different results while using the same device (“One thing I did notice is that the various CGM sensors that I was wearing almost never agreed with one another”), and different devices provided very different feedback for the same exact meal when used simultaneously (“My glucose did not react much at all, and Levels 110 rated the croissant a 6/10. A few days later, however, the exact same croissant from the same bakery at the same time jacked my glucose up”). This begs the question: what actionable feedback are these devices actually providing? In the context of diabetes, it’s quite clear: my glucose is way below my intended range, so I’ll eat some carbs; my glucose is way above my intended range, so I need a larger insulin dose. If we can’t trust that our glycemic response to a meal on Monday will predict our response to the same meal ingested at the same time on Wednesday, then I reject the premise that these devices facilitate better individualized meal planning. If a glucose monitor tells us we had an unexpectedly large glucose response after a meal, we can’t confidently leverage that information for data-driven diet optimization, as we can’t be certain that our monitor will give us the same reading the next time we consume that meal. With that in mind, it seems like these devices (in their current form, when used by people without diabetes) are just quantitatively reaffirming what we already know about how glycemic responses are generally impacted by fiber, fat, glycemic load, and proximity to exericse, with some degree of variability and measurement error. I’ve seen some people suggest that they facilitate proper maintenance of carbohydrate availability during exercise, but lifters don’t have to work very hard to ensure adequate carb availability, and “bonking” due to low carb availability during endurance exercise is an easily identifiable and unmistakable sensation (no sensors or phone apps needed). Biohacking and physiological data monitoring are all the rage right now, so I totally understand why people are so interested in continuous glucose monitors. If that’s your hobby and it brings you joy, then go for it – trying to minimize post-meal glucose excursions will do no physiological harm, and I have no reason to rain on your parade. However, I would respectfully push back at anyone who confidently asserts that this intervention is entirely harmless, or carries no risks of any kind. When we consider psychological aspects of diet and exercise habits, there is potential harm in convincing people that normal post-meal increases in blood glucose are to be feared. There is potential harm in baselessly reinforcing the idea that carbs are inherently deleterious. There is potential harm in convincing people to manage a very scary problem they didn’t know they had, and that the best way to manage it is by adopting an unnecessarily and unsustainably rigid approach to food selection. So, if continuous glucose monitors excite you, I’m not here to deprive you of a fun experiment. However, if I were concerned about my insulin sensitivity, I’d personally focus on increasing my physical activity level, losing some fat mass, and adjusting my daily fiber, protein, and calorie targets as needed. If I was having hypoglycemic episodes or suspected that I was trending toward pre-diabetes or diabetes, I’d simply pay a visit to a qualified medical professional to discuss treatment options. In that scenario, it’s possible that a continuous glucose monitor would be recommended. However, for non-clinical applications related to general health or performance 111 in people without glycemic control issues, I’m not seeing much evidence to support a beneficial effect, and there are some potential downsides when we burden ourselves with the task of micromanaging glucose fluctuations that are well within normal ranges. References 1. Merino J, Linenberg I, Bermingham KM, Ganesh S, Bakker E, Delahanty LM, et al. Validity of continuous glucose monitoring for categorizing glycemic responses to diet: implications for use in personalized nutrition. Am J Clin Nutr. 2022 Feb 4; ePub ahead of print. 2. Ferrier DR. Biochemistry (6th ed). Philadelphia: Wolters Kluwer Health/ Lippincott Williams & Wilkins; 2014:338346. 3. Howard R, Guo J, Hall KD. Imprecision nutrition? Different simultaneous continuous glucose monitors provide discordant meal rankings for incremental postprandial glucose in subjects without diabetes. Am J Clin Nutr. 2020 Oct 1;112(4):1114–9. 4. Burke LM. Ketogenic low-CHO, high-fat diet: the future of elite endurance sport? J Physiol. 2021;599(3):819–43. 5. Seidelmann SB, Claggett B, Cheng S, Henglin M, Shah A, Steffen LM, et al. Dietary carbohydrate intake and mortality: a prospective cohort study and metaanalysis. Lancet Public Health. 2018 Sep;3(9):e419–28. 112 Study Reviewed: Weight Loss Practices and Eating Behaviours Among Female Physique Athletes: Acquiring the Optimal Body Composition for Competition. Alwan et al. (2022) Understanding the Risks That Accompany the Rewards for Female Physique Athletes BY ERIC TREXLER Physique competitions take many forms, with a variety of competitive categories, including bodybuilding, physique, figure, bikini, and several others. Regardless of your chosen category, the process of preparing for and competing in a physique sport can be a very rewarding experience. However, those rewards are accompanied by some non-negligible risks. In a previous MASS article, we discussed the multifaceted physiological ramifications faced by female physique athletes. Contest preparation generally induces a state of low energy availability. Depending on the severity and duration of this state, it can lead to unfavorable downstream effects on the athlete’s hormone profile, total daily energy expenditure, satiety regulation, menstrual cycle, and bone health (2). This article also touched on disordered eating behaviors, but only briefly. That’s where the presently reviewed study (1) picks things up. The primary purpose of this study was to “investigate the weight loss history, practices and influential sources of dieting during the pre-competition period in a large cohort of [female physique athletes],” and the secondary purpose was to “determine the extent of [disordered eating] symptoms among [female physique athletes], in order to identify whether these athletes were at risk of developing an [eating disorder].” To achieve these aims, the researchers administered a survey to 191 female physique athletes who were between the ages of 18-65 years of age, had competed within the previous 12 months, had never been diagnosed with an eating disorder, and had never used banned substances. Of the 191 survey recipients, 178 of them completed it, and 20 of them were excluded based on failure to meet the inclusion criteria. The 158 included respondents competed in the bikini fitness (n = 107), figure (n = 42), women’s fitness (n = 6), and physique (n = 3) divisions. The survey consisted of the Rapid Weight Loss Questionnaire and the Eating Attitudes Test (EAT-26), which provide plenty of insight about the weight loss practices and disordered eating symptoms of respondents. These researchers administered comprehensive surveys and reported their data thoroughly, so there are a huge number of out- 113 comes presented in this paper. In the interest of brevity, this research brief will focus on only the most pertinent outcomes. One of the most eye-catching findings was that 37% of the sample had a score of ≥20 on the EAT26 questionnaire. When you get a score at or above 20, that’s indicative of a “high level of concern about dieting, body weight or problematic eating behaviors.” As a result, you’re generally encouraged to seek an evaluation from a qualified medical professional to determine if you meet the criteria for an eating disorder diagnosis. I suppose we shouldn’t be entirely surprised by this prevalence of high-risk EAT-26 scores, as we’ve seen concerning statistics in previous female physique athlete literature. For example, Walberg et al (3) administered a series of questionnaires related to disordered eating to 103 female lifters, 12 of whom had previously competed in a bodybuilding competition. In the 12 respondents with bodybuilding experience, the researchers observed high prevalence statistics for binge eating (50%), feeling miserable after binging (58%), getting uncontrollable urges to eat (50%), fear that one can’t stop eating (42%), obsession with food (58%), feeling fat despite others telling them they’re thin (50%), being terrified of becoming fat (67%), and reporting a history of anorexia (42%) or bulimia (8%). Having said all that, Walberg et al submitted this paper 3 years before I was born, and evidence-based fitness has come a long way since then. They also had only 12 respondents with bodybuilding experience, so prevalence statistics should be taken with a grain of salt. Unfortunately, they weren’t alone in presenting some concerning data related to disordered eating habits in female physique athletes. In a survey of 26 female bodybuilders published in 1998, Andersen et al (4) reported that 46% of respondents were “often or always preoccupied with food,” 60% had reported that they “lost control of their eating in the past,” 38% reported a history of post-competition binge eating episodes, and 60% reported being “very unsatisfied” with their physique, with another 8% being “unsatisfied.” Mostly due to wishful thinking, I held on to some hopes that these previous studies were presenting an ungeneralizable view of eating attitudes among female physique athletes, given that they were published decades ago and had very small sample sizes. Unfortunately, the presently reviewed results reported by Alwan et al (from a large, contemporary sample) seem to reinforce the fact that disordered eating habits are a prevalent concern among female physique athletes. In fact, the presently reviewed results might underestimate the true severity of the issue, given that Alwan and colleagues excluded competitors with a previously diagnosed eating disorder. While the number of EAT-26 scores above 20 is concerning, it’s also fair to point out that some eating disorder questionnaires have survey items that don’t really make sense in the context of bodybuilding or physique sports. For example, your EAT-26 is unfavorably impacted if you are “aware of the calorie content of foods” that you eat, “think about burning up calories when [you] exercise,” “eat diet foods,” “display self-control 114 around food,” or “engage in dieting behavior.” I wish we could pretend the presently reviewed results are simply a matter of ungeneralizable survey selection, but unfortunately that’s not the case. The participants in this study reported engaging in some really deleterious dieting behaviors, regardless of context. As shown in Figure 1, around 35% of participants reported “never” having binge eating episodes, around 75% reported “never” relying on self-induced vomiting to lose weight, and around 20% reported “never” relying on laxatives, diet pills, or diuretics to lose weight. Almost 80% of respondents reported using laxatives, diet pills, or diuretics at least once a month, nearly 65% of respondents reported binge eating at least once a month, and almost 25% of respondents reported self-induced vomiting at least once a month. These numbers raise an interesting question: does physique sport participation cause eating disorders, or do people with elevated eating disorder risk gravitate toward physique sports? I suspect that the answer is quite similar to a recent discussion pertaining to the relationship between diet tracking and disordered eating. In that MASS review, I mentioned that individuals with high risk of eating disorder development are more likely to do quantitative diet tracking than people with low risk of eating disorder development. I also discussed the evidence suggesting that the combination of elevated eating disorder predisposition, perfectionist concerns, excessively restrictive guidelines, and rigid restraint (5) might lead to a scenario in which diet tracking exacerbates issues related to 115 disordered eating. In contrast, diet tracking appeared to be quite benign in the absence of these contextual factors. I suspect a similar relationship between physique sport participation and eating disorders. Evidence suggests that people with high eating disorder risk are more likely to gravitate toward physique sports than people with low eating disorder risk (5), and the presently reviewed study found that novice figure competitors had higher EAT-26 scores (indicating higher eating disorder risk) than more experienced figure competitors and competitors in divisions that require less muscle mass and allow for slightly higher body-fat levels in judging criteria. Thus, it seems that physique sports tend to attract individuals with elevated eating disorder risk, and the intensity of competition can exacerbate these tendencies, especially for competitors who have ambitious goals (e.g., competitors in divisions with more extreme judging criteria for leanness and muscularity) and have a lot of ground to cover (e.g., novice competitors who aren’t starting their prep within “striking distance” of their on-stage physique). As such, I don’t suspect that physique competition is independently and robustly causative of eating disorders, but I very much suspect that physique competition can reveal and exacerbate the tendency to engage in disordered eating behaviors and deleterious weight loss behaviors among individuals with a predisposition to eating disorder development. It’s also very possible that those tendencies would not have materialized, or would have materialized in less extreme or deleterious ways, if the individual did not choose to participate in a physique sport. To lean on a very clichéd analogy, we can think of watering a seed. You can water soil all you want, but it won’t produce a plant unless a seed is present. Similarly, a seed may lay dormant in the soil, but won’t give rise to a plant without sufficient water. When an individual has an underlying predisposition to disordered eating habits, a seed is present. When they turn up the intensity by engaging in physique-focused competition, and combine this competition ambition with excessively restrictive guidelines, rigid restraint, and the selection of a division with judging criteria that virtually insist upon perfectionist concerns, that provides a whole lot of water for that seed to yield a plant. I should also note that, up to this point, we’ve exclusively focused on female physique athletes. However, as discussed previously in MASS, this topic is extremely applicable to male physique athletes as well, who self-report higher rates of eating disorders and body image disorders than the general population (6). I assume that very few MASS readers are clinically trained practitioners whose scope of practice includes eating disorder diagnosis or treatment, so you might be wondering what this has to do with you. As it turns out, this might actually have a lot to do with you. Survey respondents were asked to identify the individuals who influence their dieting practices, and the results might surprise you. 52.2% of respondents stated that nutritionists/dietitians were “not influential” to them, while a whopping 82.2% said that their doctor was not influential. This means that, aside from doctors, only parents were described as 116 “not influential” more frequently than nutritionists/dietitians, with more favorable numbers reported for coaches, friends, romantic partners, training partners, other physique athletes, and “internet.” The biggest influences seemed to be coaches (by a wide margin) and other physique athletes, although a non-negligible percentage of respondents acknowledged being influenced by their romantic partner, training partner, and people on the internet. This mirrors the results of another recent study, which found that physique athletes primarily get their information and guidance from websites, internet forums, coaches, and successful physique athletes (7). It would be intuitive to assume that doctors, nutritionists, and dietitians have the largest impact on the diet practices of female physique athletes. Given the high prevalence of disordered eating symptoms in this population, that’d be ideal, as these individuals are most equipped to diagnose eating disorders, oversee treatment, and skillfully advise a dieter who is at elevated risk of developing an eating disorder. These practitioners are also best equipped to navigate the physiological ramifications that may result from aggressive dieting. Nonetheless, it’s quite possible that you, as a coach, fellow competitor, experienced fitness enthusiast, or “person who engages in fitness conversations on the internet,” have a larger impact on a physique athlete’s dieting strategies than a doctor or dietitian. So, what can you do to have a helpful influence, or at least avoid having a harmful influence? If you’re a coach, always stay within your scope of practice. Promote and implement strategies that emphasize flexible dietary re- straint (5). Help your clients with their goal setting, calibration of expectations, and mental approach to dieting and competing. Keep your eyes open for signs of eating disorder predisposition, elevated eating disorder risk, or disordered eating behaviors, and refer to the appropriate clinicians when necessary. If you’re a competitor or fitness enthusiast who frequently participates in online (or real-life) fitness discussions, set a positive example by promoting sustainable dieting practices and flexible dietary restraint, and avoid reinforcing strategies or perspectives that may broadly fuel disordered eating habits, perfectionist concerns, or body image concerns. In addition, speaking with kindness and empathy can go a long way, whereas toxic online fitness environments can fuel some of the psychopathological traits and perspectives that promote greater frequency and severity of disordered eating habits and body image issues. Finally, when you observe others displaying concerning behaviors or signs of disordered eating habits, you might privately express this concern to the individual (depending on the nature of your relationship with them), while being mindful of respecting personal boundaries and relevant scope of practice boundaries. In short, eating disorders and deleterious weight loss behaviors are a prevalent concern among physique athletes. This doesn’t suggest that no one should ever compete in physique sports, but individuals who suspect they have an elevated risk or predisposition for eating disorder development should practice extreme caution when considering if, why, and how they might participate in a 117 physique-focused sport. Finally, it’s important to recognize that coaches, athletes, fitness enthusiasts, and members of online fitness communities have an outsized influence on how physique athletes approach dieting, whether they like it or not. That responsibility shouldn’t be taken lightly, and coaches, competitors, fitness enthusiasts, and members of online fitness communities should carefully consider how their words and actions might influence high-risk dieters. 6. Lenzi JL, Teixeira EL, de Jesus G, Schoenfeld BJ, de Salles Painelli V. Dietary Strategies of Modern Bodybuilders During Different Phases of the Competitive Cycle. J Strength Cond Res. 2021 Sep 1;35(9):2546–51. 7. Mitchell L, Hackett D, Gifford J, Estermann F, O’Connor H. Do Bodybuilders Use Evidence-Based Nutrition Strategies to Manipulate Physique? Sports. 2017 Sep 29;5(4):76. References 1. Alwan N, Moss SL, Davies IG, Elliott-Sale KJ, Enright K. Weight loss practices and eating behaviours among female physique athletes: Acquiring the optimal body composition for competition. PloS One. 2022;17(1):e0262514. 2. Alwan N, Moss SL, Elliott-Sale KJ, Davies IG, Enright K. A Narrative Review on Female Physique Athletes: The Physiological and Psychological Implications of Weight Management Practices. Int J Sport Nutr Exerc Metab. 2019 Nov 1;29(6):682-689. 3. Walberg JL, Johnston CS. Menstrual function and eating behavior in female recreational weight lifters and competitive body builders. Med Sci Sports Exerc. 1991 Jan;23(1):30–6. 4. Andersen RE, Brownell KD, Morgan GD, Bartlett SJ. Weight loss, psychological, and nutritional patterns in competitive female bodybuilders. Eat Disord. 1998 Jun 1;6(2):159–67. 5. Helms ER, Prnjak K, Linardon J. Towards a Sustainable Nutrition Paradigm in Physique Sport: A Narrative Review. Sports. 2019 Jul 16;7(7):172. 118 Study Reviewed: Effect of Morning and Evening Exercise on Energy Balance: A Pilot Study. Creasy et al. (2022) Comparing the Effects of Morning Versus Evening Workouts on Total Daily Energy Expenditure BY ERIC TREXLER In recent years, there has been increasing interest in the intersection between circadian biology and nutrition. For example, we’ve written MASS reviews about whether the thermic effect of feeding is greater in the morning than in the evening, and whether the thermic effect of feeding is impacted by irregular meal schedules. Due to our circadian rhythm, we experience physiological changes impacting energy expenditure and macronutrient metabolism throughout the day, so it’s intuitive to wonder if our meal timing and distribution might have a noteworthy impact on energy expenditure patterns and, by extension, total daily energy expenditure. Shifting the focus from energy expenditure to training adaptations, the MASS team has also addressed (on three separate occasions) whether or not there’s a universally optimal time of day to train (one, two, three). The presently reviewed study (1) merges these two separate lines of inquiry, as it investigates whether or not morning and evening cardio workouts have divergent effects on energy expenditure and body composition changes. This was a pilot study; as a result, the researchers recruited a fairly small sample of participants, and were primarily interested in assessing the feasibility and tolerability of the training intervention, while gathering some preliminary data to fuel future hypotheses. A total of 33 weight-stable participants between the ages of 18-56 years with overweight or obesity were randomly assigned to complete morning cardio workouts (n = 18) or evening cardio workouts (n = 15). Morning workouts occurred between 6:00-10:00, and evening workouts occurred between 15:00-19:00. The exercise intervention was 15 weeks long, and incrementally progressed from moderate to vigorous intensity (70% of maximum heart rate to 80%) and from 187.5 kcal/session (750 kcal/week) to 500 kcal/session (2000 kcal/ week) by the 11th week of the program. They prescribed exercise based on energy expenditure at 70%, 75%, and 80% of maximum heart rate, which was measured during a maximal baseline test. They provided an example as follows: if a participant burned 9.3 kcal/min at 80% of their max heart rate, they’d need to exercise for 54 minutes at this particular intensity in order to burn 500kcals in the exercise session (500 kcal divided by 9.3 kcal/min results in an exercise time of 54 minutes). 119 Body composition was measured via DXA before and after the training program. At the beginning and end of the intervention, the researchers also measured total daily energy expenditure over 14-day periods using doubly labeled water. In addition, participants wore an accelerometer and another wearable device to track sleep habits. On top of that, resting energy expenditure was measured via indirect calorimetry in a subset of participants (n = 23). Finally, average energy intake was estimated by combining the doubly labeled water data with estimated changes in total body energy based on changes in fat mass and fat-free mass. Since this was a pilot study aimed at gathering preliminary data (rather than forming generalizable conclusions), the researchers reported their results fully, but opted not to perform inferential statistical tests. Based on retention and adherence statistics, it looks like both approaches (morning and evening exercise) were feasible and tolerable for participants. Compared to baseline, the morning exercise group experienced a drop in sleep duration (-10.2 ± 42.6 min/day), whereas the evening exercise group experienced an increase (+26.6 ± 73.0 min/day). The morning group started sleeping earlier at night but waking up earlier for exercise, whereas the evening group started sleeping earlier at night but slept in a little bit later. When it comes to energy expenditure, the researchers reported that morning and evening exercise yielded divergent effects for various components of energy expenditure (Table 1). For example, the morning exercise group experienced a larger increase in total daily energy expenditure, a smaller drop in non-exercise energy expenditure, and a larger increase in resting energy expenditure, but also a larger increase in energy intake. Note that these are merely directional statements, and do not imply statistically significant effects (as no statistical tests were conducted). Having said all of that, both groups had fairly similar changes in body composition, with small reductions in body weight and fat mass (~1-1.5kg), and negligible changes in fat-free mass. You could argue that there was a very 120 slight advantage leaning in favor of greater weight loss in the evening exercise group, but differences were small. While I think the researchers did an excellent job with this study, I don’t find the energy expenditure differences to be particularly compelling. First of all, we’re looking at a very small sample of participants and some pretty small differences between the two groups. Beyond that, we’re looking at incomplete data; for example, non-exercise energy expenditure was calculated based on the resting energy expenditure values (which were only measured in a subsample of participants) and an assumed (not measured) value of energy burned during exercise sessions. Similarly, energy intake was calculated based on losses of lean mass and fat mass (and their estimated energy densities), and DXA estimates come with some unavoidable measurement error. However, the most important reason that I’m not getting worked up about the energy expenditure results (yet) is that they aren’t corroborated by the body composition changes. In many cases, we’re primarily interested in energy expenditure outcomes because of their assumed connection to long-term changes in body composition. These energy expenditure data would imply that more favorable energy expenditure changes were occurring in the morning exercise group, but the weight loss and fat loss results lean slightly in favor of the evening exercise group. When looking at other studies on the topic, it seems that the data are truly mixed, with some research reporting more favorable weight loss from morning exercise (2), some research reporting more favorable weight loss from evening exercise (3), and other research showing no significant difference (4). So, these energy expenditure results are certainly interesting, but I’m going to wait for replication in a larger study before I place too much confidence in them. Based on the totality of the available evidence, I don’t think we should be deciding between morning and evening workouts based on the expectation of differential effects on energy expenditure or fat loss. As mentioned previously, the MASS team has thrice discussed whether resistance training sessions completed in the morning or evening might lead to differential training adaptations (one, two, three). When Dr. Zourdos most recently addressed the topic, he did a fantastic job summarizing the current state of the evidence, so I’ll merely restate his conclusions rather than trying to reinvent the wheel. As he explains more fully in his Volume 4 article, the current evidence suggests that lifters can make very similar long-term strength and hypertrophy gains whether they choose to train in the morning or the evening. However, if you’re accustomed to training in the evening, you might experience a transient 5-10% strength reduction when you first switch to morning workouts, but this should only last a few weeks. In addition, there might be some modest advantages (namely increased motivation and lower session RPE) when you opt to train at your preferred training time. Finally, as noted in the presently reviewed study, it doesn’t seem that nighttime workouts have a particularly negative impact on sleep duration or quality, as long as you aren’t completing very intense exercise within an hour or so of bedtime (5). In conclusion, there don’t 121 seem to be major, persistent physiological costs or benefits associated with completing your workouts in the morning or the evening. With this in mind, you should feel empowered to train at whatever time suits your preferences and fits your schedule. References 1. Creasy SA, Wayland L, Panter SL, Purcell SA, Rosenberg R, Willis EA, et al. Effect of Morning and Evening Exercise on Energy Balance: A Pilot Study. Nutrients. 2022 Jan;14(4):816. 2. Willis EA, Creasy SA, Honas JJ, Melanson EL, Donnelly JE. The effects of exercise session timing on weight loss and components of energy balance: midwest exercise trial 2. Int J Obes 2005. 2020 Jan;44(1):114–24. 3. Di Blasio A, Di Donato F, Mastrodicasa M, Fabrizio N, Di Renzo D, Napolitano G, et al. Effects of the time of day of walking on dietary behaviour, body composition and aerobic fitness in post-menopausal women. J Sports Med Phys Fitness. 2010 Jun;50(2):196–201. 4. Teo SYM, Kanaley JA, Guelfi KJ, Dimmock JA, Jackson B, Fairchild TJ. Effects of diurnal exercise timing on appetite, energy intake and body composition: A parallel randomized trial. Appetite. 2021 Dec 1;167:105600. 5. Stutz J, Eiholzer R, Spengler CM. Effects of Evening Exercise on Sleep in Healthy Participants: A Systematic Review and Meta-Analysis. Sports Med. 2019 Feb;49(2):269–87. 122 VIDEO: Time-Efficient Programming Strategies Part II BY MICHAEL C. ZOURDOS Part 1 of our time efficiency series provided examples of training strategies which can be used to decrease training time. However, there are certain circumstances which warrant training twice per day, in which further adjustments are needed to accommodate two-a-days. Therefore, part 2 of this series provides practical examples for how time-efficient programming strategies can be used to make two-a-days feasible. Click to watch Michael's presentation. 123 Relevant MASS Videos and Articles 1. Rest-Pause Training is a Viable Strategy to Maximize Hypertrophy. Volume 1 Issue 3. 2. Back-to-Back Champs: The Agonist-Antagonist Superset. Volume 4 Issue 3. 3. Minimum Effective Dose Training Part 2. Volume 5 Issue 9. 4. Time-Efficient Programming Strategies Part 1. Volume 6 Issue 3. 5. Is Training Twice A Day For You? Volume 6 Issue 3. References 1. Iversen VM, Norum M, Schoenfeld BJ, Fimland MS. No time to lift? Designing time-efficient training programs for strength and hypertrophy: a narrative review. Sports Medicine. 2021 Oct;51(10):2079-95. 2. Storey A, Wong S, Smith HK, Marshall P. Divergent muscle functional and architectural responses to two successive high intensity resistance exercise sessions in competitive weightlifters and resistance trained adults. European journal of applied physiology. 2012 Oct;112(10):3629-39. 3. Bartolomei S, Malagoli Lanzoni I, Di Michele R. Two vs. One Resistance Exercise Sessions in One Day: Acute Effects on Recovery and Performance. Research Quarterly for Exercise and Sport. 2021 Dec 19:1-6. █ 124 Interpreting Failure and Non-Failure Data BY ERIC HELMS You might have noticed the studies comparing failure versus non-failure for hypertrophy outcomes often conflict. We’ve reviewed many of them in MASS, and not only do they tend to conflict with one-another, but even within the MASS team, we don’t always see eye-to-eye when interpreting the impact of failure. Why is that? In this video, you’ll understand why interpreting these data is challenging. Click to watch Eric's presentation. 125 Relevant MASS Videos and Articles 1. Bonus: Reps in Reserve and Hypertrophy. Volume 4, Issue 3. 2. VIDEO: Emerging Concepts in Velocity-Based Training. Volume 4, Issue 8. 3. Velocity Loss is Conceptually Flawed. Volume 4, Issue 12. 4. The Most Comprehensive Look at Proximity to Failure Yet. Volume 5, Issue 8. References 1. Karsten, B., Fu, Y. L., Larumbe-Zabala, E., Seijo, M., & Naclerio, F. (2021). Impact of Two High-Volume Set Configuration Workouts on Resistance Training Outcomes in Recreationally Trained Men. Journal of Strength and Conditioning Research, 35(Suppl 1), S136–S143. 2. Martorelli, S., Cadore, E. L., Izquierdo, M., Celes, R., Martorelli, A., Cleto, V. A., et al. (2017). Strength Training with Repetitions to Failure does not Provide Additional Strength and Muscle Hypertrophy Gains in Young Women. European Journal of Translational Myology, 27(2), 6339. 3. Santanielo, N., Nóbrega, S. R., Scarpelli, M. C., Alvarez, I. F., Otoboni, G. B., Pintanel, L., et al. (2020). Effect of resistance training to muscle failure vs non-failure on strength, hypertrophy and muscle architecture in trained individuals. Biology of Sport, 37(4), 333–341. 4. Pareja-Blanco, F., Rodríguez-Rosell, D., Sánchez-Medina, L., Sanchis-Moysi, J., Dorado, C., Mora-Custodio, R., et al. (2017). Effects of velocity loss during resistance training on athletic performance, strength gains and muscle adaptations. Scandinavian Journal of Medicine & Science in Sports, 27(7), 724–735. 5. Vieira, A. F., Umpierre, D., Teodoro, J. L., Lisboa, S. C., Baroni, B. M., Izquierdo, et al. (2021). Effects of Resistance Training Performed to Failure or Not to Failure on Muscle Strength, Hypertrophy, and Power Output: A Systematic Review With Meta-Analysis. Journal of Strength and Conditioning Research, 35(4), 1165–1175. 6. Grgic, J., Schoenfeld, B. J., Orazem, J., & Sabol, F. (2021). Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy: A systematic review and meta-analysis. Journal of Sport and Health Science, S20952546(21)00007-7. 7. Hackett, D. A., Johnson, N. A., & Chow, C. M. (2013). Training practices and ergogenic aids used by male bodybuilders. Journal of Strength and Conditioning Research, 27(6), 1609–1617. 8. Vieira, J. G., Sardeli, A. V., Dias, M. R., Filho, J. E., Campos, Y., Sant’Ana, L., et al. (2021). Effects of Resistance Training to Muscle Failure on Acute Fatigue: A Systematic Review and Meta-Analysis. Sports Medicine, 10.1007/s40279-021-01602-x. 9. Pelland, J. C., Robinson, Z. P., Remmert, J. F., Cerminaro, R. M., Benitez, B., John, T. A., et al. (2022). Methods for Controlling and Reporting Resistance Training Proximity to Failure: 126 Current Issues and Future Directions. Sports Medicine, 10.1007/s40279-022-01667-2. 10. Zourdos, M. C., Goldsmith, J. A., Helms, E. R., Trepeck, C., Halle, J. L., Mendez, K. M., et al. (2021). Proximity to Failure and Total Repetitions Performed in a Set Influences Accuracy of Intraset Repetitions in Reserve-Based Rating of Perceived Exertion. Journal of Strength and Conditioning Research, 35(Suppl 1), S158–S165. 11. Halperin, I., Malleron, T., Har-Nir, I., Androulakis-Korakakis, P., Wolf, M., Fisher, J., et al. (2022). Accuracy in Predicting Repetitions to Task Failure in Resistance Exercise: A Scoping Review and Exploratory Meta-analysis. Sports Medicine, 52(2), 377–390. 12. Beck, M., Varner, W., LeVault, L., Boring, J., & Fahs, C. A. (2020). Decline in Unintentional Lifting Velocity Is Both Load and Exercise Specific. Journal of Strength and Conditioning Research, 34(10), 2709–2714. █ 127 Just Missed the Cut Every month, we consider hundreds of new papers, and they can’t all be included in MASS. Therefore, we’re happy to share a few pieces of research that just missed the cut. It’s our hope that with the knowledge gained from reading MASS, along with our interpreting research guide, you’ll be able to tackle these on your own. If you want to peruse our full journal sweep, you can find it here, and you can find our historical archive here. 1. Ma et al. A scoping review of interventions to improve strength training participation 2. Halperin et al. Accuracy in Predicting Repetitions to Task Failure in Resistance Exercise: A Scoping Review and Exploratory Meta-analysis 3. Hirschberg. Challenging Aspects of Research on the Influence of the Menstrual Cycle and Oral Contraceptives on Physical Performance 4. Wehrstein et al. Eccentric Overload during Resistance Exercise: A Stimulus for Enhanced Satellite Cell Activation 5. Hu et al. Effects of Transcranial Direct Current Stimulation on Upper Limb Muscle Strength and Endurance in Healthy Individuals: A Systematic Review and Meta-Analysis 6. Skattebo et al. Increased Mass-Specific Maximal Fat Oxidation Rate with Small versus Large Muscle Mass Exercise 7. Yacyshyn and McNeil. Intrinsic Neuromuscular Fatigability in Humans: The Critical Role of Stimulus Frequency 8. Nóbrega et al. Muscle Hypertrophy Is Affected by Volume Load Progression Models 9. Kassiano et al. Partial range of motion and muscle hypertrophy: not all ROMs lead to Rome 10. Lochbaum et al. Sport psychology and performance meta-analyses: A systematic review of the literature 11. Nugent et al. The Effects of High-Repetition Strength Training on Performance in Competitive Endurance Athletes: A Systematic Review and Meta-Analysis 12. Baena-Marín et al. Velocity-Based Resistance Training on 1-RM, Jump and Sprint Performance: A Systematic Review of Clinical Trials 13. Mang et al. Aerobic Adaptations to Resistance Training: The Role of Time under Tension 14. Lim et al. Does a Higher Protein Diet Promote Satiety and Weight Loss Independent of Carbohydrate Content? An 8-Week Low-Energy Diet (LED) Intervention 15. Potter et al. Effects of Exercise Training on Resting Testosterone Concentrations in Insufficiently Active Men: A Systematic Review and Meta-Analysis 16. Grgic. Effects of post-exercise cold-water immersion on resistance training-induced gains in muscular strength: a meta-analysis 128 17. Campos et al. Importance of Carbohydrate Quality: What Does It Mean and How to Measure It? 18. Kwan and Helms. Prevalence, Magnitude, and Methods of Weight Cutting Used by World Class Powerlifters 19. Wachsmuth et al. The Impact of a High-Carbohydrate/Low Fat vs. Low-Carbohydrate Diet on Performance and Body Composition in Physically Active Adults: A Cross-Over Controlled Trial 20. Gebel and Ding. Using Commercially Available Measurement Devices for the Intake-Balance Method to Estimate Energy Intake: Work in Progress 129 Thanks for reading MASS. The next issue will be released to subscribers on May 1, 2022. Copy editing by Lauren Colenso-Semple Graphics and layout by Kat Whitfield 130