V O L U ME 5 , ISS U E 1
JANUARY 2 0 2 1
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 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
Do Knee Sleeves Boost Maximal Squat Strength?
Short answer: yes. Longer answer: yes, but only a little bit.
16
BY MI CHAEL C. ZOUR DOS
Prime Time is in Order for Two-a-Days
A priming session is a light training session that can improve performance within the
next 48 hours. MASS hasn’t covered this topic in nearly four years, but a new study
may confirm the efficacy of priming sessions. This article breaks down all the available
data on the subject.
31
BY ER I C HEL MS
In the Right Conditions, Carbohydrate Mouth Rinsing May
Enhance Lifting Performance
We describe glycogen as “fuel,” but we aren’t cars. It’s more complex than being
unable to train hard once glycogen runs out. You’re also held back by central
mechanisms that sense fuel is low. This study suggests in certain conditions, those
central mechanisms can be somewhat reversed with a carbohydrate mouth rinse.
43
BY ER I C T R EXL ER
Does Getting Lean Make Your Next Bulk More Effective?
It’s increasingly common to hear that excessive body fat can impede hypertrophy
during a bulk, primarily due to reduced insulin sensitivity. This article aims to review
a recent rodent study related to this concept, then explore the evidence supporting
and contradicting the idea of getting lean to potentiate muscle gains.
59
BY GR EG NUCKOL S
Does Eccentric Training Always Cause More Muscle
Damage?
Eccentric training causes more muscle damage than concentric training in untrained
subjects, but how much can we adapt to it over time? A recent study examined
muscle damage responses following 10 weeks of maximal concentric-only and
eccentric-only training. It found that, after about seven weeks, neither eccentric nor
concentric still caused substantial muscle damage.
70
BY MI CHAEL C. ZOUR DOS
Time to Reframe the Proximity to Failure Conversation
It’s time to stop asking if training a few reps shy of failure is okay, as I think we have
enough evidence to support this notion. Rather, it’s time to reframe the proximity to failure
conversation and ask, how far can we train from failure? It may be farther than you think.
86
BY ER I C T R EXL ER
Do Vegan Diets Hinder Hypertrophy?
There are many defensible reasons to shift toward a more plant-based diet, but
plant-based proteins have lower quality scores and have been shown to induce
smaller acute increases in muscle protein synthesis than animal proteins. So, will a
vegan diet hinder your gains? Read on to find out.
101
BY GR EG NUCKOL S
Can We Predict Muscle Fiber Type Distributions from Rep
Max Tests?
It’s commonly believed that people with greater strength endurance have a greater
proportion of slow-twitch muscle fibers, and that people with worse strength
endurance have a greater proportion of fast-twitch fibers. A recent study examined
this belief, and found that it contains a grain of truth … but only a grain.
115
BY MI CHAEL C. ZOUR DOS
VIDEO: Accentuated Eccentrics
The effectiveness of overloading your eccentrics to improve concentric
outcomes is equivocal. However, new data suggest the concentric load may be
a pivotal factor in determining if accentuated eccentrics are effective. This video
examines the landscape of accentuated eccentrics to enhance strength and
provides insight into the new data.
118
BY ER I C HEL MS
VIDEO: Pros and Cons of Body Composition Testing
Wouldn’t it be great if you had a DXA scanner at home so you could ditch the scale
and mirror and get a weekly scan to assess progress? Actually, it wouldn’t be great;
it would lead you astray to get scanned that frequently. In this video you’ll learn
the difference between the perception and the data on the precision of the most
common body composition assessment devices and you’ll learn how, and how
often it’s reasonable to get tested.
Letter From the Reviewers
W
elcome to 2021 and Volume 5 of MASS! As always, we have a great issue
lined up to kick off the new year.
Starting in the nutrition department, Dr. Trexler covered a study
investigating whether a vegan diet based on mycoprotein could support muscle protein
synthesis at a similar level as an omnivorous diet. He also tackled the topic of whether
you can potentiate hypertrophy by cutting before you bulk. Is it true that leaner people
gain muscle more efficiently? And where did that idea originate in the first place?
Dr. Helms’s article this month discussed whether carbohydrate mouth rinsing could
improve lifting performance. The discussion section of this article was very well-done,
detailing the ins and outs of the situations where carbohydrate mouth rinsing has been
shown to be effective, and when it hasn’t panned out.
In the training department, Dr. Zourdos’s first article discussed whether, and under
what circumstances, lifting early in the day could improve performance during a
training session taking place later on the same day. His second article revisits an
old favorite subject in MASS: whether training to failure is beneficial for promoting
hypertrophy and strength outcomes. Greg’s three articles cover a) the relationship (or
lack thereof) between reps-to-failure performance and muscle fiber types, b) the time
course of habituating to pretty extreme eccentric training, and c) the impact of knee
sleeves on strength, power, and strength endurance.
Finally, in the video department, Dr. Helms discusses the pros and cons of body
composition testing, and Dr. Zourdos covers accentuated eccentric training.
After a turbulent 2020, we’re grateful to everyone reading this. We’re hoping that things
can broadly return to normal in 2021, and we’ll be doing our best to keep you up-to-date
about strength, hypertrophy, and physique science throughout this upcoming year.
Sincerely,
The MASS Team
Eric Helms, Greg Nuckols, Mike Zourdos, and Eric Trexler
5
Study Reviewed: Neoprene Knee Sleeves of Varying Tightness Augment Barbell Squat One
Repetition Maximum Performance Without Improving Other Indices of Muscular Strength,
Power, or Endurance. Machek et al. (2020)
Do Knee Sleeves Boost
Maximal Squat Strength?
BY GREG NUCKOLS
Short answer: yes. Longer answer: yes, but only a little bit.
6
KEY POINTS
1. Researchers compared three different knee sleeve conditions in a crossover
study: a thin nylon sleeve, appropriately fitting neoprene sleeves, and extra-tight
neoprene sleeves.
2. Subjects were tested for maximal squat strength, maximal knee extension
strength, knee extension strength endurance, jump height, and barbell power and
velocity with 90% and 100% of 1RM loads.
3. The neoprene sleeves improved 1RM squat strength by about 5kg relative to the
nylon sleeve condition. Furthermore, the tight sleeves and appropriately fitting
sleeves caused similar increases.
4. None of the other performance measures differed between knee sleeve conditions.
K
nee sleeves are so popular in powerlifting that even boomers like
Eric Helms wear them. Some lifters
merely wear them for comfort, but most lifters believe that sleeves improve their squatting performance, at least to some degree. In
fact, many competitive lifters intentionally
use sleeves that are a size too small, in the
hopes that extra-tight sleeves will give them
an additional performance boost. However,
until recently, no research had investigated whether knee sleeves improve maximal
squatting strength.
neoprene knee sleeves of two different tightnesses (one pair sized according to manufacturer guidelines, and one pair that was one
size smaller than recommended). Performance was similar with all three sleeves for
all tests except for squat 1RM. Both neoprene
sleeves allowed the subjects to squat about
5kg more than they could with the loose nylon sleeves, but there were no differences in
squat strength between the tests with normal
and extra-tight neoprene sleeves.
The presently reviewed study (1) examined
the effects of three different types of knee
sleeves on 1RM squat strength, 1RM knee
extension strength, knee extension strength
endurance, jump height, and barbell power
and velocity at 90% and 100% of 1RM. 15
reasonably experienced squatters completed
this set of tests in three different sessions with
three different types of knee sleeves: thin nylon sleeves (which effectively served as the
control condition), and powerlifting-style
Purpose
Purpose and Hypotheses
The purpose of the study was to assess whether strength, power, or strength endurance
would differ when subjects were tested with
a control knee sleeve (a thin sleeve that offers
virtually no compressive support), an appropriately sized neoprene knee sleeve, or a tighter-than-recommended neoprene knee sleeve.
Hypotheses
No hypotheses were directly stated, but the
7
wording of the introduction suggests that the
researchers expected that the neoprene knee
sleeves would improve performance relative
to the control sleeve.
Subjects and Methods
Subjects
15 male subjects, aged 18-35, participated
in this study. All subjects regularly participated in resistance training and squatted at
least 1.5-times body mass. People with “major experience or a discernible preference toward knee sleeves” were also excluded. You
can see more information about the subjects
in Table 1.
Experimental Design
Subjects completed three testing visits in a
randomized, counterbalanced, crossover design; one visit consisted of performance tests
with a control knee sleeve, one consisted of
performance tests with an appropriately sized
knee sleeve (henceforth referred to as “normal sleeves”), and one consisted of performance tests with tighter-than-recommended
knee sleeves (henceforth referred to as “tight
sleeves”). The testing sessions were separated by seven days, and the first testing session
was preceded by a screening session to ensure
the subjects met the inclusion criteria, and to
gather body composition data on the subjects.
Subjects were asked to refrain from lower
body training for at least 72 hours before each
testing session, and to keep a food log for 48
hours preceding each testing session.
The control knee sleeves were made of an
85%/15% nylon/elastane blend, and have
been shown to offer very little compressive
support (2). The normal sleeves and tight
sleeves were both neoprene knee sleeves
from SBD, which might be worn in powerlifting meets. The normal sleeves were sized
based on SBD’s sizing chart, and the tight
sleeves were one size smaller than would be
recommended by SBD’s sizing chart.
Each testing session consisted of four exercises in this order: counter-movement jump,
squat jump, squat 1RM, unilateral knee extension 1RM, and unilateral knee extension
reps to failure with 75% of 1RM. The counter-movement and squat jump tests were both
performed using a Vertec; subjects were given three attempts at each style of jump. Peak
power and mean power were estimated using
validated regression equations, but the only
aspect of the equation that would be affected
within each subject session-to-session was
jump height, so I’m going to ignore the esti-
8
mates of mean and peak power (since they’re
just linear transformations of jump height,
which is what was actually being measured).
1RM squat testing was performed to legal
powerlifting depth (verified by the lead lab
technician, who was a USAPL powerlifting
judge). Subjects warmed up to 90% of their
self-reported 1RM, and were then blinded to
the load on the bar for subsequent 1RM attempts. Peak velocity, peak power, and range
of motion were measured for their attempts at
90% of self-reported 1RM and their final successful 1RM attempt of each session using a
linear position transducer. Subjects were allowed to self-select their squat stance, footwear, and bar position (which were required
to be the same for all three testing sessions
within each subject), but were not allowed
to use a belt or wrist wraps. Knee extension
1RM strength and strength endurance were
assessed for the subjects’ dominant legs using a Cybex knee extension machine. The
strength endurance test was performed three
minutes after the completion of the 1RM attempts, using 75% of the highest 1RM attained in the testing session; the rep cadence
was fixed to 2-1-2-1 cadence (pause at the
bottom, concentric, pause at the top, eccentric) for both knee extension tests.
Findings
Squat 1RM was significantly greater in the
normal sleeve and tight sleeve conditions than
the control sleeve condition (+5kg; 166 vs.
161kg), but no other performance measure differed between conditions. Dietary intake also
didn’t differ significantly between conditions.
9
Interpretation
To start with, let’s discuss the ways that knee
sleeves may improve squat performance. The
two research-based explanations are that they
may generally improve muscle coordination
via enhanced proprioception (3), and they
can increase muscle and joint temperatures
(4), which may improve viscoelastic properties of the quadriceps and enhance muscular
enzyme function. Two additional possibilities are that the sleeves store and release
elastic energy across the front of the sleeve
(generating a knee extension moment) when
the knees bend and the neoprene stretches, or
that the material of the sleeves compresses
between the hamstrings and calves when the
knees are in deep flexion, and thus exert an
equal and opposite knee extension moment.
Of course, a combination of these possible
mechanisms may contribute.
At first, the takeaway from this study seems
to be pretty straightforward: wearing neoprene
knee sleeves improves maximal squat strength
10
WEARING NEOPRENE KNEE
SLEEVES IMPROVES MAXIMAL
SQUAT STRENGTH, AND
YOU’RE PROBABLY FINE TO
SIMPLY USE APPROPRIATELY
SIZED SLEEVES INSTEAD OF
BUYING AN EXTRA-TIGHT PAIR
IN THE HOPES OF GETTING
AN ADDITIONAL BOOST.
by an average of ~5kg (~11lb), and you’re
probably fine to simply use appropriately
sized sleeves instead of buying an extra-tight
pair in the hopes of getting an additional boost.
However, there are a few counterarguments
that someone could make against such a simplistic interpretation. For starters, squat 1RM
strength sticks out like a sore thumb in the
results. There were numerous other performance measures (counter-movement jump
height, squat jump height, maximal knee extension strength, knee extension strength endurance, and squat power and velocity at 90%
and 100% of 1RM), and squat 1RM was the
only performance measure that was affected
by the use of knee sleeves. Does that seem
plausible? Or is it likely that the squat 1RM
results are merely false positives?
I’ll argue that it is plausible for squat 1RM
to be the only performance measure affect-
ed. Starting with jump height, we know that
jump height is a product of the capacity to
generate force with the lower body musculature, and the shortening velocity of those
muscles. Shortening velocity, in the context
of jumps, is a function of the stretch-shortening cycle, the inherent contractility of the
muscles, and the ability to rapidly recruit
and synchronize muscle activation. There’s
no mechanism (that I’m aware of) by which
neoprene knee sleeves would be expected to
affect the stretch-shortening cycle or the inherent contractile characteristics of the lower body muscles, though generalized compression may increase muscle activation
slightly (5). Furthermore, we can see that the
effect of knee sleeves on maximal force output is modest (~5kg, or 3%). While maximal
squat strength is associated with jumping
ability (6), a 3% increase in maximal squat
strength would be expected to only increase
jump height to a negligible degree (~1cm).
Furthermore, jumping is a high-velocity
movement that people generally perform
with bare knees, and so the use of sleeves
by sleeve-naive individuals may have had a
slight negative effect on their coordination
and timing (though, honestly, I think this
possibility is a bit of a reach). Thus, it’s not
very surprising that the knee sleeves didn’t
affect jump performance. I also don’t find
the lack of differences between knee sleeve
conditions to be particularly surprising for
squat velocity and power at 90% and 100%
of 1RM. The methods section doesn’t specify that subjects were instructed to move every rep as fast as possible, and people generally don’t focus on maximally accelerating
near-max squats all the way through the con-
11
centric unless they’re specifically instructed
to do so. Peak velocity and peak power in
the squat generally occur above the sticking
point with near-max loads, and most people
tend to let off the gas a bit once they clear
the sticking point, focusing more on stability and balance than maximizing concentric
velocity and power. Finally, I don’t think
the lack of differences in knee extension
strength and strength endurance are particularly surprising either. The prescribed rep
cadence included a two-second pause at the
top of each rep, where the sleeves would be
assisting the least (if we assume they exert a
positive effect via either compressive force
behind the knee, or elastic force across the
front of the knee). In other words, I’d expect
that knee sleeves may improve knee extension torque at 90 degrees of knee flexion,
but would have a much smaller effect at 0
degrees of knee flexion; the rep cadence
used in the present study ensured that performance would be primarily limited by
knee extension strength at 0 degrees of knee
flexion (at the top of each rep). Therefore, I
do find it pretty unsurprising that squat 1RM
strength was the only performance measure
affected by the various sleeve conditions in
the present study.
A second potential argument against the simplistic interpretation of the results relates to
the fact that the participants were not experienced with squatting in knee sleeves. Numerous high-level raw powerlifters believe that
wearing extra-tight knee sleeves improves
their squat performance, to the point that the
International Powerlifting Federation had to
make a rule stating that knee sleeves couldn’t
be so tight that they required another person
to help you put them on. Now, it’s entirely
possible that all of these lifters are merely
placeboing themselves, or they’re just scrapping for any advantage they can get in a sport
with very strict equipment restrictions (even
if they believe that advantage only amounts
to a kilo or two). However, it is possible that
wearing extra-tight neoprene sleeves can improve performance a bit relative to appropriately sized sleeves, but the sleeve-naive subjects in the present study simply didn’t know
how to take advantage of extra-tight sleeves.
I really don’t think a lack of experience squatting in sleeves affected the results of the present study (in my experience, sleeves just don’t
change the overall feel of the movement very
much, though your mileage may vary), and
I’m skeptical that extra-tight sleeves offer a
meaningful benefit over appropriately sized
sleeves, but it’s at least plausible, especially
if we assume that sleeves do offer some degree of elastic rebound.
Finally, it’s worth reiterating that the control condition in the present study didn’t involve squatting with bare knees – it involved
squatting with thin, nylon sleeves. The nylon
sleeves are unlikely to offer any meaningful
elastic rebound or bunch up behind the knees
to any meaningful degree, but if the benefits of sleeves are related to their ability to
keep muscles and joints warm and enhance
proprioception, it’s at least possible that the
subjects in the present study still enjoyed
those benefits when squatting with the nylon
sleeves (albeit to a lesser degree than when
using neoprene sleeves, in all likelihood).
Thus, it’s possible that the average difference
12
between squatting with bare knees and squatting with neoprene sleeves would have been
somewhat larger than 5kg. I’d be surprised if
the difference was larger than 10kg, but it’s at
least possible that the use of nylon sleeves in
the control condition led to a slight underestimation of the performance-enhancing effects
of neoprene knee sleeves.
The presently reviewed study builds on a
prior study that Mike reviewed in MASS (7).
In the previous study, squatting in sleeves
was shown to improve bar velocity at 70%
of 1RM, when compared to a bare-knee con-
KNEE SLEEVES MAY
IMPROVE SUBJECTIVE
COMFORT AND FEELINGS
OF STABILITY, AND ALSO
IMPROVE MAXIMAL
SQUAT STRENGTH.
dition. Additionally, 9 out of 15 subjects reported that squatting with sleeves was more
comfortable than squatting with bare knees,
and 10 out of 15 reported that sleeves helped
their squats feel more stable (compared to 2
subjects who reported less comfort and decrements in perceived stability). This study
expands on those prior findings, showing
that sleeves can also slightly improve 1RM
squat strength.
Overall, knee sleeves may improve subjective comfort and feelings of stability, and also
improve maximal squat strength. However,
they may not improve other measures of lower body strength and power performance, including jump height, knee extension strength,
and knee extension strength endurance. Furthermore, if you want to use knee sleeves in
your training, you’re probably fine to just
stick with the manufacturer’s recommended
sizing – wearing extra-tight sleeves probably won’t benefit you much (and as someone who owns a pair of appropriately sized
sleeves and a pair of extra-tight sleeves, I’ve
gotta tell you that the slight decrease in size
leads to an exponential increase in annoyance
when you’re putting the sleeves on or taking
them off). Since we don’t yet have evidence
13
APPLICATION AND TAKEAWAYS
Knee sleeves slightly improve squat 1RM. Since there aren’t clear downsides to
sleeve usage, and since most people report that sleeves enhance comfort and
enhance feelings of stability, it may be worth picking up a pair if you compete in
powerlifting, if your knees feel achy or unstable, or if you simply want to boost your
squat max by a smidgen. However, they don’t make a night-and-day difference, so
don’t feel like you need to get a pair if you’re cheap or if finances are tight.
showing that training in sleeves improves
longitudinal adaptations, it may not be worth
paying for a pair of knee sleeves if you don’t
compete in powerlifting. However, if you
have achy knees that might benefit from some
extra warmth, if you compete in powerlifting
(in a federation that allows knee sleeves but
SINCE THERE AREN’T
CLEAR DOWNSIDES TO
SLEEVE USAGE, AND
SINCE MOST PEOPLE
REPORT THAT SLEEVES
ENHANCE COMFORT
AND ENHANCE
FEELINGS OF STABILITY,
IT MAY BE WORTH
PICKING UP A PAIR.
not knee wraps), or if you just want a new toy
that might help your squats feel a bit stronger
and more comfortable, there are a couple of
good reasons to get a pair of knee sleeves,
and no good reason (other than cost) to not
use them.
Next Steps
I’d be interested in seeing a nearly identical
study on elite powerlifters who are accustomed to squatting in super tight sleeves.
It’s possible that they would squat a bit more
in tight sleeves than appropriately fitting
sleeves. The only thing I’d add to the present study’s design would be the inclusion of a
bare-knee condition.
14
References
1. Machek SB, Cardaci TD, Wilburn DT, Cholewinski MC, Latt SL, Harris DR, Willoughby
DS. Neoprene Knee Sleeves of Varying Tightness Augment Barbell Squat One Repetition
Maximum Performance Without Improving Other Indices of Muscular Strength, Power,
or Endurance. J Strength Cond Res. 2020 Nov 16. doi: 10.1519/JSC.0000000000003869.
Epub ahead of print. PMID: 33201154.
2. Troynikov O, Ashayeri E, Burton M, Subic A, Alam F, Marteau S. Factors influencing
the effectiveness of compression garments used in sports. Procedia Engineering. 2010;
2(2):2823-2829. doi: 10.1016/j.proeng.2010.04.073
3. Herrington L, Simmonds C, Hatcher J. The effect of a neoprene sleeve on
knee joint position sense. Res Sports Med. 2005 Jan-Mar;13(1):37-46. doi:
10.1080/15438620590922077. PMID: 16389885.
4. Mazzuca SA, Page MC, Meldrum RD, Brandt KD, Petty-Saphon S. Pilot study of the
effects of a heat-retaining knee sleeve on joint pain, stiffness, and function in patients
with knee osteoarthritis. Arthritis Rheum. 2004 Oct 15;51(5):716-21. doi: 10.1002/
art.20683. PMID: 15478166.
5. Gu H-M, Chae W-S, Yang C-S, Kang N-J, Jang J-I. The effects of wearing spandex
pants on impact forces and muscle activity during drop landing. Korean Journal of Sport
Biomechanics. 2009 Sept;19(3). doi: 10.5103/KJSB.2009.19.3.603
6. Wisløff U, Castagna C, Helgerud J, Jones R, Hoff J. Strong correlation of maximal squat
strength with sprint performance and vertical jump height in elite soccer players. Br J
Sports Med. 2004 Jun;38(3):285-8. doi: 10.1136/bjsm.2002.002071. PMID: 15155427;
PMCID: PMC1724821.
7. Sinclair J, Mann J, Weston G, Poulsen N, Edmundson CJ, Bentley I, Stone M. Acute
effects of knee wraps/sleeve on kinetics, kinematics and muscle forces during the barbell
back squat. Sport Sciences for Health. 2019 Nov 19:1-1.
█
15
Study Reviewed: Delayed Potentiation Effects on Neuromuscular Performance After
Optimal Load and High Load Resistance Priming Sessions Using Velocity Loss. GonzalezGarcia et al. (2020)
Prime Time is in Order for
Two-A-Days
BY MICHAEL C. ZOURDOS
A priming session is a light training session that can improve
performance within the next 48 hours. MASS hasn’t covered this
topic in nearly four years, but a new study may confirm the efficacy
of priming sessions. This article breaks down all the available data
on the subject.
16
KEY POINTS
1. A priming session is a low-volume training session designed to improve strength or
power performance sometime within the next 48 hours.
2. This study examined the effects of two different priming conditions: 1) Smith
machine squatting with a load that maximized power production (~61% of 1RM)
and 2) Smith machine squatting with 80% of 1RM. Outcomes were vertical jump
height and squat velocity and power six hours after the priming workouts. The
prescription in both priming conditions was two sets, with each set terminated at
20% velocity loss.
3. The 80% priming session improved vertical jump and squat velocity, while the
priming session with a load that maximized power output did not improve outcome
measures. These findings suggest that performing a few reps at 80% of 1RM can
improve performance later in the day.
N
early 30 years ago, Primetime prepared for the World Series by playing an NFL game. Almost four years
ago, MASS covered a study that showed that
explosive training (5 sets of 4 reps at 40% of
1RM on squat jump) could enhance strength
and power 24-48 hours later. In other words,
performing light training or a “priming”
session 48 hours before a performance test
may be better than just resting. The potential application of this is wide-ranging. For
example, a powerlifter may alter their taper
to include a priming session 24-48 hours before a heavy day. Despite these potential implications, most of the data in this area are
focused on the ability of a priming session
to enhance power performance. There is little
uniformity among the existing research regarding the proper prescription of a priming
session. The reviewed crossover design study
from Gonzalez-Garcia (1) examined if priming sessions could enhance vertical jump,
squat velocity and power at 80% of 1RM,
and “optimal load” (a load at which a subject maximized power output) six hours later.
11 trained lifters (10 men, 1 woman) tested
those outcomes in a control condition (i.e.,
no priming) or six hours after two different
priming sessions. The priming sessions were
two sets of squats with a 20% velocity loss
using each subject’s optimal load, or two sets
of squats with a 20% velocity loss using 80%
of 1RM. Findings showed that vertical jump
height, power, and velocity were greater in
the 80% condition than the control condition;
however, there was no difference between
outcome measures in the optimal load versus
the control condition. There were also no statistical differences between the 80% and optimal load conditions; however, the average
velocity at 80% of 1RM tended to be greater in the 80% priming condition (p = 0.061).
This study’s findings suggest that a priming
session using 80% of 1RM can enhance performance six hours later. Although this study
yielded positive results, the overall body of
17
literature is ripe with ambiguity regarding
priming sessions. Therefore, this article will
cover the existing literature on the topic and
speculate on the following concepts:
did not specify if they thought there would be
a difference between priming sessions.
1. Discuss how to use priming during taper
weeks and to enhance performance at a
powerlifting competition or for a max day.
Subjects
2. Demonstrate how to use priming sessions
as a staple of mid-week training.
3. Discuss various methods of prescription
for priming sessions.
4. Examine how far before a max test is a
priming session most useful (i.e., same
day, 24 hours, or 48 hours).
Purpose and Hypotheses
Purpose
The purpose of this study was to examine if
squat priming sessions with a load that maximizes power production (optimal load) or a
load corresponding to 80% of 1RM could improve lifting velocity and power output and
vertical jump performance six hours later.
Hypotheses The researchers hypothesized that both priming sessions would enhance performance, but
Subjects and Methods
11 subjects (10 men and 1 woman) participated. The publication provides little information about their training status, but from the
details given in Table 1, the subjects probably
had a few years of training experience.
Study Overview
Subjects completed the crossover design
study over five sessions, with sessions separated by exactly 48 hours. In the morning,
the first session tested 1RM on the Smith
machine squat, determined “optimal load,”
and tested velocity and power output at
80% of 1RM. Subjects performed two reps
at each 10% increment between 30-90%
of 1RM, and the load at which the highest
power output was achieved (measured by a
linear position transducer) was used as the
optimal load in subsequent sessions. Velocity and power on the 80% set were also recorded. The second session was performed
in the afternoon, and retested optimal load
and velocity, and power at 80%. The purpose of this second session was to familiar-
18
ize subjects further and ensure the optimal
load and 80% testing was reliable between
morning and afternoon sessions.
Sessions three, four, and five served as the experimental conditions, and were performed in
a randomized order. In the optimal load condition, subjects performed a morning priming
session of two sets of squats at their optimal
load. They stopped each set once a 20% velocity loss threshold had been reached. Six
hours later, they tested the outcome measures
(vertical jump height, average velocity, and
power with the optimal load, average velocity, and power with 80% of 1RM). In the 80%
condition, subjects performed a morning
priming session of two sets of squats with
80% of 1RM and stopped each set at a 20%
velocity loss, then tested all the outcome
measures six hours later. In the control condition, subjects did not perform a priming session and only tested the outcome measures
in the afternoon at the same time of day as
the other conditions. Additionally, in all three
conditions, subjects completed the short recovery stress scale in the morning. The optimal load and 80% conditions completed
the scale before the priming session, and the
control condition completed the scale at the
same time of day as it was completed in the
other condition. Subjects then completed the
scale again in the afternoon before the outcome measures to assess training readiness.
This scale is a 0 (not at all) to 6 (extreme)
scale (lower scores indicate greater stress and
lower readiness) assessing physical and men-
19
tal performance capability, activation balance, and overall stress. Subjects provided
a session rating of perceived exertion (RPE)
value after the morning priming sessions in
the optimal load and 80% conditions. Figure
1 displays the complete study protocol.
Subjects performed vertical jumps with their
hands on their hips and no knee flexion during
the flight phase. All jumps were performed
on a force platform, and jump height was calculated with the following equation: [(Take
off velocity2) / (2 × Gravity)]. For optimal
load and 80% velocity power, three single
repetitions were completed at each load with
two minutes of rest between reps. Velocity
and power were averaged over the three reps.
Findings
Priming Session Observations
Subjects used an average of 60.9% for their
optimal load and 111.84kg for their 80% squat
load during the priming sessions. As expected, subjects performed more reps, squatted at
a faster velocity, and recorded a lower RPE
during the priming session in the optimal
load versus the 80% priming condition. Table 2 shows the complete observations from
the priming sessions.
Performance Findings
The 80% priming session led to statistically
higher vertical jump height and squat power and velocity at 80% of 1RM in the afternoon session compared to the control condition. Vertical jump height and 80% average
velocity also tended to be better in the 80%
condition than in the optimal load condition,
as p-values were close to the level of significance, as seen in Table 2. However, the percentage difference (3.5%) for vertical jump
height between the 80% and optimal load
conditions was significantly greater (p =
20
0.030) in favor of the 80% condition. There
were no significant differences for performance metrics between the optimal load and
control conditions. Table 3 shows the specific
findings for all performance metrics. Figure 2
displays a comparison of the percentage difference in velocity compared to the control
condition for both priming conditions.
Readiness Scale
There were no differences between conditions for any readiness variables before the
afternoon performance testing.
Interpretation
Alex Ovechkin had not yet raised the great-
21
est trophy in all of sports when we last covered priming sessions. That review covered a
study from Tsoukos et al (2), which showed
that performing 5 (sets) × 4 (reps) at 40% of
1RM on the squat jump improved vertical
jump height 24 and 48 hours later, but did not
affect isometric leg press strength. The presently reviewed study from Gonzalez-Garcia
(1) also found that a priming session can
benefit performance, but had clear differences compared to Tsoukos. First, the currently
reviewed study only examined performance
six hours after the priming session. Additionally, this study found that a reasonably heavy
priming session (i.e., 80% of 1RM) effectively increased performance at the same load.
Unfortunately, the other priming studies add
to the lack of uniformity regarding prescription and what outcome measures are most
likely to be improved. Therefore, there is a
lot to speculate on, so this interpretation will:
1. Discuss previous literature on priming
sessions.
22
2. Speculate on what the appropriate priming prescription and time frame are for
max strength improvement.
3. Discuss various options to implement
priming into programming.
Previous Literature on Priming
A review from Harrison (3) suggested mixed
results for priming sessions, which was confirmed in a recent systematic review from
Mason et al (4). Mason’s review included
studies that used various priming methods
(i.e., resistance training, endurance running
and cycling, and sprint running and cycling).
The 20 studies which specifically used resistance training priming also had equivocal results; however, many of these studies
examined explosive performance (usually
jumping) as an outcome. Seven of the resistance training studies in Mason’s systematic
review also used resistance training as an outcome; however, I did not find all seven resistance training studies from Mason applicable
(more on that later). Table 4 summarizes the
relevant studies from the Mason systematic
review, the presently reviewed research, and
the aforementioned Tsoukos study.
Table 4 shows inconsistent results for priming.
Perhaps most importantly for MASS readers is
that only one study, Cook et al (6), has demonstrated priming to directly improve maximal
strength. However, the Tsoukos (2) and Linnamo (8) studies, which did not see a benefit for max strength, investigated isometric
strength, which may not be indicative of dynamic strength. Cook (6) found that subjects
squatted, on average, 7kg more and benched
5kg more in the afternoon when performing
a 3RM squat and bench press in the morning
compared to not training in the morning. The
finding from Cook seems a bit counterintuitive as it suggests that if you want to perform
your best max triple in the afternoon, you
should first perform a max triple in the morning. Still, it could just be an elongated example of postactivation potentiation (PAP). Increased number of reps to failure as a result of
PAP exercise (discussed previously: one, two)
has been shown 5-10 minutes after a heavy set
at 85-90% of 1RM in both the back squat (9)
and bench press (10). Therefore, although the
Cook study may seem questionable on the surface, one set of three reps, even maximal, really isn’t too fatiguing. I’m not ready to say that
a max lift should be performed in the morning to prepare for an afternoon session, but the
idea may not be outlandish. That being said,
it’s clear that high volume resistance training
early in the day harms performance later in the
day. I purposefully omitted multiple studies
(11, 12) from Table 4 due to the use of a high
volume workout in the morning, which predictably found diminished performance later
in the day.
Researchers (3) have argued that specificity is important for priming sessions to be
of benefit. In other words, the priming prescription (i.e., initial session) should be of
similar intensity to the performance test. This
assertion does seem to be true in some cases seen in Table 4. The previously reviewed
Tsoukos study (2) found that explosive jumps
squats enhanced rate of force development,
but not maximal force production. However,
Ekstrand et al (5) had throwers perform a set
to failure at 85% of 1RM on squat and some
23
lighter power clean sets in the morning and
observed increased distance on the explosive
shot put throw in the afternoon. The presently
reviewed study is also only partially in support of the specificity argument. As a reminder, Gonzalez-Garcia (1) found that priming at
80% improved velocity and power at 80%
of 1RM later in the day. However, priming
with optimal load (a max power load) did not
improve performance at the same load later
in the day, and priming with 80% enhanced
vertical jump, whereas priming with the optimal load did not. Based upon the currently
reviewed study’s results and those of Cook
(6), the specificity argument may be specific to strength performance, which would be
a clear takeaway for MASS; however, it’s a
thin one. While the Cook results are impressive, the present results only show improved
velocity at 80% of 1RM, which is not the
same as directly showing enhanced strength.
Priming Prescription for Strength Improvement
When we zero in on priming to improve
strength, the relevant studies are the present
one (1), Gonzalez-Badillo (7), Cook (6), and
Tsoukos (2), with Gonzalez-Badillo being the
only one we haven’t analyzed yet. As seen in
Table 4, Gonzalez-Badillo found that subjects were able to use a heavier load (+ 4.9%)
to produce a velocity of 1.0 m/s on the bench
press 48 hours after performing sets to about
a 6 RPE (i.e., 3 × 4 at an 8RM load) but did
not find performance improvement 48 hours
following 3 × 8 at the same 8RM load. These
findings add to the Tsoukos findings, which
showed enhanced performance 24-48 hours
after priming exercise. If priming can be use-
ful 24-48 hours before performance, I think
that is much more impactful for strength and
powerlifting purposes than same-day priming. Same-day priming may have great utility for collegiate or professional athletes who
are often already doing walkthroughs, morning skates, and shootarounds the morning of
a game. These athletes have the time and resources to get in a priming session six hours
before a game. However, if you’re a powerlifter, you will most likely be lifting in the
morning on meet day. Of course, there are
afternoon or evening sessions at nationals or
worlds. If you’re in a heavier weight class,
you may even be in an afternoon session in
a local meet, and in these cases, a morning
priming session may be warranted. Nonetheless, the vast majority of competitive lifting
starts in the morning, and using a same-day
priming session is not possible.
This 24-48-hour window could be applied
THIS 24-48-HOUR
WINDOW COULD BE
APPLIED DURING THE
WEEK OF A POWERLIFTING
MEET OR MAX DAY, OR
EVEN DURING REGULAR
TRAINING WEEKS.
24
during the week of a powerlifting meet or max
day, or even during regular training weeks.
So, it means that if your meet or test day is
on Saturday, then it may be advisable to perform a priming session on Thursday or Friday
instead of merely taking these days off. Questions remain, though, regarding whether you
should perform explosive training as a primer
or heavy-ish training, and whether this priming session should be performed either 24
or 48 hours before the test. I don’t think we
know those answers yet, but if you buy into
the aforementioned specificity argument, then
performing two or three singles at 80% of
1RM 24-48 hours before training or a strength
test may be the way to go. If you’re worried
that’s too heavy, then I’d go with 3 × 3 at 4060% of 1RM as the primer. Of course, it’s not
a binary choice between those two options; instead, these examples point out that you may
consider either explosive or moderate intensity training, but the volume should be low
either way. I’d encourage you to try both the
explosive and moderate loading, and both the
24- and 48-hour time frames to see what feels
best for you. It’s possible that your current
method of training may be responsible for determining which priming strategy is effective.
For example, if you squat nearly every day at
high intensities, then an 80% squat 24 hours
before a competition may be a good idea.
However, if you only squat twice per week,
25
adding in an 80% squat 24 hours out could be
a bit nerve-wracking and even fatiguing. Table 5 shows examples of implementing various priming options for a powerlifting meet or
test day, given a previous training frequency
of three times per week on the squat and bench
press and twice per week on the deadlift.
As with any sample table, this table is just
a template and not comprehensive in nature.
Nonetheless, the template does try to consider some nuances, such as performing lifts on
the same day and reducing volume in the final
week. Further, on the “40-60% 24 hours before” option, the training is a bit more aggressive earlier in the week, consistent with the
more aggressive approach training 24 hours
before competition. I did not provide an example of using 80% training 24 hours before
competition, but if you squat at a high intensity 4 or 5 times per week, then that may be
something you are willing to consider (more
on this later).
For some, using a taper may already contain
a priming strategy of sorts; if not, it can be
a bit unnerving trying something new, which
brings me to the second application of these
24-48 hour priming strategies. That is, to include them as part of your normal training
program. You could do this by simply placing a low-volume power day in the middle
of each week. This could be done with either
the 40-60% or 80% variety. If you train a lift
on Monday, Wednesday, and Friday, then
it’s possible that using a priming session on
Wednesday could potentiate Friday’s session.
In fact, our group found that an 80% primer
(or power day) performed in between hypertrophy-type and strength-type sessions each
week for six weeks led to more volume and
greater strength adaptation than when a primer day wasn’t performed immediately before
the strength session (13). It’s also possible
that the mid-week priming session could
have the extra benefit of facilitating recovery,
as training with light loads may improve recovery following a damaging training session
(14 - MASS Review). Although a mid-week
priming session has merit, we should also understand that this probably comes at the expense of volume. If you squat three times per
week and turn your mid-week session into a
primer, you will sacrifice another day of volume; thus, this strategy probably shouldn’t
always be used. Oftentimes, I’ll include a
mid-week priming day only in the last week
or two of a training block when someone is
preparing for a powerlifting meet or test day.
This strategy serves multiple purposes:
1. It should allow for better heavy days (usually Friday or Saturday in my programs)
than previous weeks.
ALTHOUGH A MID-WEEK
PRIMING SESSION HAS
MERIT, WE SHOULD ALSO
UNDERSTAND THAT THIS
PROBABLY COMES AT THE
EXPENSE OF VOLUME.
26
2. It may help to serve as a taper leading into
the meet/test.
3. By accomplishing numbers one and two,
more accurate attempt selection can be
planned for the competition.
Since this has gotten pretty practical, let
me cap off the article with a bit of personal coaching and training experience. As a
coach, I only program a priming session 24
hours before a competition if I have already
successfully tried it with a lifter in training
and he/she is comfortable with it. With potentially promising data but no consensus on
how to go about this, I would suggest toying around with the priming prescription on
various training weeks to see what strategy is
comfortable for you and your lifter. I also find
a primer to come in handy when lifters have
to travel for competition. If the competition is
on Saturday, I would typically like to get the
last training session in on Thursday; however, I’ve had situations where lifters traveled
all day Thursday, so I opted for a 40% primer session on Friday. This avoided a 72-hour
rest for a high-frequency lifter leading into
a big meet and, most importantly, it put the
lifter in a position to succeed. In other words,
forcing a training session at either 4 a.m. (before travel) on Thursday or after a long day
of travel would not have gone well. I have
also experimented with 24-hour priming sessions at 80% of 1RM during normal training with considerable success. Specifically,
during a 75 consecutive day cycle of squatting, I max squatted every other day (instead
of every day) and performed 1 × 1 at 7-8RPE
on the days in between. I chose an RPE target instead of a percentage to deal with the
strength fluctuation of frequent maxing. The
training cycle felt fantastic (although I, unfortunately, lifted with Helms for part of this
cycle). This last paragraph is, of course, experience-based, so it should be taken for what
it’s worth, which is a non-scientific coaching
and lifting anecdote. However, in an area of
research that is still in the early stages of development, hopefully this anecdote is useful
to conceptualize the topic, even if you don’t
have the same experience.
Next Steps
Due to the lack of uniformity in the existing literature and the general lack of data on
strength performance, there are a ton of options for the next step, but I’ll just mention one
to keep it simple. I’d like to see a crossover
design study on the squat and bench press,
which uses a 40% primer, a 60% primer, an
80% primer, and a control condition and then
tests 1RM 48 hours later. This design would
have a great deal of utility both for planning
tapers and for using mid-week primers, as
discussed earlier.
27
APPLICATION AND TAKEAWAYS
1. The reviewed study showed that performing a low-volume priming session at 80%
of 1RM on the Smith machine squat enhanced squat velocity at 80% of 1RM and
vertical jump height six hours later.
2. Overall, there is interesting data around priming sessions; however, the existing
studies lack uniformity in both prescription and outcomes.
3. If using priming for maximal strength performance, it is wise to consider both
heavier (i.e., 80% of 1RM) and lighter (i.e., 40-60% of 1RM) priming strategies. It is
advisable to try these strategies 24 or 48 hours before a heavy day in training and
see how they work. If this strategy seems successful, it may be worth considering a
priming session as part of your taper if you are a powerlifter.
28
References
1. González-García J, Giráldez-Costas V, Ruiz-Moreno C, Gutiérrez-Hellín J, RomeroMoraleda B. Delayed potentiation effects on neuromuscular performance after optimal
load and high load resistance priming sessions using velocity loss. European Journal of
Sport Science. 2020 Nov 3:1-28.
2. Tsoukos A, Veligekas P, Brown LE, Terzis G, Bogdanis GC. Delayed effects of a lowvolume, power-type resistance exercise session on explosive performance. The Journal of
Strength & Conditioning Research. 2018 Mar 1;32(3):643-50.
3. Harrison PW, James LP, McGuigan MR, Jenkins DG, Kelly VG. Resistance priming
to enhance neuromuscular performance in sport: evidence, potential mechanisms and
directions for future research. Sports Medicine. 2019 Jun 15:1-6.
4. Mason B, McKune A, Pumpa K, Ball N. The Use of Acute Exercise Interventions as
Game Day Priming Strategies to Improve Physical Performance and Athlete Readiness in
Team-Sport Athletes: A Systematic Review. Sports Medicine. 2020 Aug 10:1-20.
5. Ekstrand LG, Battaglini CL, McMurray RG, Shields EW. Assessing explosive power
production using the backward overhead shot throw and the effects of morning resistance
exercise on afternoon performance. The Journal of Strength & Conditioning Research.
2013 Jan 1;27(1):101-6.
6. Cook CJ, Kilduff LP, Crewther BT, Beaven M, West DJ. Morning based strength training
improves afternoon physical performance in rugby union players. Journal of science and
medicine in sport. 2014 May 1;17(3):317-21.
7. González Badillo JJ, Rodríguez Rosell D, Sánchez Medina L, Ribas Serna J, López
López C, Mora Custodio R, Yáñez García JM, Pareja Blanco F. Short-term Recovery
Following Resistance Exercise Leading or not to Failur
8. Linnamo V, Häkkinen K, Komi PV. Neuromuscular fatigue and recovery in maximal
compared to explosive strength loading. European journal of applied physiology and
occupational physiology. 1997 Dec 1;77(1-2):176-81.
9. de Freitas Conrado M, Rossi FE, Colognesi LA, Zanchi NE, Lira FS, Cholewa JM,
Gobbo LA. Postactivation Potentiation Improves Acute Resistance Exercise Performance
and Muscular Force in Trained Men. Journal of strength and conditioning research. 2018
Nov.
10. Alves RR, Viana RB, Silva MH, Guimarães TC, Vieira CA, de Santos DA, Gentil PR.
Postactivation Potentiation Improves Performance in a Resistance Training Session in
Trained Men. J. Strength Cond. Res. 2019 Sep 25.
29
11. Raastad T, Hallén J. Recovery of skeletal muscle contractility after high-and moderateintensity strength exercise. European journal of applied physiology. 2000 Jun
1;82(3):206-14.
12. Häkkinen K, Pakarinen A, Alen M, Kauhanen H, Komi PV. Neuromuscular and
hormonal responses in elite athletes to two successive strength training sessions in one
day. European journal of applied physiology and occupational physiology. 1988 Mar
1;57(2):133-9.
13. Zourdos MC, Jo E, Khamoui AV, Lee SR, Park BS, Ormsbee MJ, Panton LB, Contreras
RJ, Kim JS. Modified daily undulating periodization model produces greater performance
than a traditional configuration in powerlifters. The Journal of Strength & Conditioning
Research. 2016 Mar 1;30(3):784-91.
14. Bartolomei S, Totti V, Griggio F, Malerba C, Ciacci S, Semprini G, Di Michele R. UpperBody Resistance Exercise Reduces Time to Recover After a High-Volume Bench Press
Protocol in Resistance-Trained Men. Journal of Strength and Conditioning Research.
2019 Mar 4.
█
30
Study Reviewed: Carbohydrate Mouth Rinse Improves Resistance Exercise Capacity in the
Glycogen-Lowered State. Durkin et al. (2020)
In the Right Conditions,
Carbohydrate Mouth Rinsing May
Enhance Lifting Performance
BY ERIC HELMS
We describe glycogen as “fuel,” but we aren’t cars. It’s more
complex than being unable to train hard once glycogen runs out.
You’re also held back by central mechanisms that sense fuel is low.
This study suggests in certain conditions, those central mechanisms
can be somewhat reversed with a carbohydrate mouth rinse.
31
KEY POINTS
1. In a crossover trial, resistance-trained men performed high volume muscular
endurance training with the squat and bench press (six sets to failure at
40% of 1RM on each) following a lower-body cycling session the night prior
to deplete leg glycogen. Before each set, they rinsed their mouths with a
solution containing sucralose in the placebo condition, or maltodextrin in the
intervention condition.
2. During the carb mouth rinse condition, the participants performed significantly
more total volume and more reps while squatting, but not while bench pressing.
This indicates that in glycogen-depleted muscle, central mechanisms play a role
in hindering performance. Further, this centrally mediated fatigue can be at least
partially reversed by activating carbohydrate sensing receptors in the mouth.
3. While this finding helps us understand the nature of fatigue, trials in which
carbohydrate mouth rinsing enhance lifting performance are the minority.
In studies where mouth rinsing enhances lifting performance, the protocols
are high-volume, high-effort, long-duration, and often in a state of lower
carbohydrate availability.
M
y review of the present study (1) is
the latest chapter in MASS on the
role carbohydrates play in resistance training. This study investigated the
use of a carbohydrate mouth rinse during
resistance training to enhance performance.
As many studies on endurance exercise
(2) and a few on resistance exercise (3, 4;
MASS Review) have shown, simply swishing your mouth with a carbohydrate solution for 10 seconds and spitting it out can
increase performance. If you view carbohydrates as food that provides fuel, and fatigue
as the result (at least in part) of fuel being
low, you might be puzzled by the ability of
carbohydrates to mitigate fatigue without
actually being consumed. This study is an
example of that puzzling outcome. A group
of resistance-trained men participated in a
crossover study in which they mouth rinsed
before each set of a high volume, muscular
endurance session (six sets at 40% 1RM to
failure on the squat and bench press), with
a carbohydrate solution in one crossover
arm and an artificially sweetened placebo
solution in the other. The night before these
sessions, they completed a glycogen-depleting cycling session. Interestingly, squat
but not bench press volume was enhanced
relative to placebo in the carbohydrate
mouth rinse condition, indicating that local glycogen depletion mediated the potential for a mouth rinse to aid performance.
In this review, we’ll discuss the interesting
interactions between actual carbohydrate
availability, oral sensing of potential carbohydrate availability, fatigue, and performance. Finally, I’ll discuss the extent to
which the present study’s findings might
apply in some circumstances.
32
Purpose and Hypotheses
Purpose
This study’s purpose was to observe the effect
of carbohydrate mouth rinsing on low-load,
high-volume resistance training to failure in a
low-energy but fed state, after a glycogen-depleting cycling bout the night prior.
Hypotheses No explicit hypothesis was stated. However,
based on the introduction, it appears the authors suspected a mouth rinse would improve
low-load volume capacity relative to a placebo, in the specific condition of low carbohydrate availability.
Subjects and Methods
Subjects
12 healthy, resistance-trained men (age: 22 ±
4 years; height: 1.79 ± 0.05 m; weight: 78.7 ±
7.8 kg; bench press 1-RM: 87 ± 21 kg; squat
1-RM: 123 ± 19 kg) participated in this study.
They had a minimum of two years of lifting
experience, and performed the squat and
bench press at least weekly.
Study Overview
This was a placebo-controlled, single-blind
(only the participants were blinded) crossover
trial in a randomized order. Before either arm
of the crossover, the participants came to the
lab on two separate occasions to perform an
incremental cycling trial to determine aerobic power, and a 4RM testing session for the
squat and bench press to estimate their 1RMs.
To begin each arm of the crossover, the participants came to the lab in the evening, and
performed a glycogen-depleting interval
training session on an exercise bike. Briefly,
two-minute intervals at 90% of aerobic power were alternated with two minutes at 50%,
and when the participants could no longer
maintain 60 revolutions per minute (RPM),
the intervals were incrementally reduced by
10%. When the participants couldn’t maintain 60 RPM at 70% power, the bout ceased.
These bouts lasted over 60 minutes.
After the glycogen-depleting cycling, the re-
33
searchers provided chocolate milk with ~42g
of carbohydrate and 268kcal, and a standardized dinner of chicken and vegetables consisting of ~12g of carbohydrate and 408kcal.
The following morning, the participants
consumed a standardized low-carbohydrate,
low-energy breakfast of eggs on toast (~14g
carbohydrate, 223kcal) two hours before the
training session. The participants were instructed to eat nothing else outside of these
meals during this time period, and to only
consume water ad libitum. The aim of this
controlled diet was to achieve only partial repletion of glycogen in the lower body and to
mimic training in a state of both being fed,
but during an energy deficit. Table 1 provides
a summary of the nutritional information of
the standardized meals and drinks.
The resistance training sessions consisted of
six sets at 40% of 1RM to failure, starting with
the bench press, followed by the squat. Participants completed reps at their own tempo,
but were explicitly told not to pause between
reps. You can do a lot of reps at 40% 1RM,
but not allowing long pauses between reps
probably prevented the participants from doing even more reps due to repeatedly catching
their breath, which is common during high
repetition sets (you’ll notice in the Findings
section that the participants completed fewer
than 30 reps per set on squats, and fewer than
40 reps per set on bench).
carbohydrate. At the conclusion of the study,
the participants were asked to guess the order
that they received the placebo and the carbohydrate solution. Only 5 out of 12 participants correctly guessed the order, indicating
that they were indeed guessing, and blinding
was successful.
Total volume was recorded (sets x reps x
load) for both exercises, as were arousal and
mood using the “Felt Arousal Scale” and
the “Feeling Scale” immediately prior to the
training session, at the halfway mark, and immediately following the training session.
Findings
There were no significant differences between conditions for arousal or mood, and
the authors did not report this data.
Combined squat and bench press volume
loads with individual data points are shown
in Figure 1. Volume was significantly greater
during the carb mouth rinse condition (9354
± 2051 kg vs. 8525 ± 1911 kg, p = 0.010;
The participants rested two minutes between
sets, and five minutes between exercises. 30
seconds before each set began, they rinsed
their mouths with either a 6.4% maltodextrin solution sweetened with sucralose, or a
taste-matched sucralose solution devoid of
34
ES = 0.418, 95% CI of difference = 238kg to
1419kg).
Mean total reps for the bench press (Figure 2)
in the carb mouth rinse condition were slightly higher than placebo, but not significantly
and the effect size was pretty small (120 ± 24
vs. 115 ± 22 reps, p = 0.146; ES = 0.198, 95%
CI of difference = -1.9 to 11.0 reps). For the
squat however (Figure 3), significantly more
reps were performed during the carb mouth
rinse condition than during the placebo condition (107 ± 26 vs. 92 ± 16 reps, p = 0.017;
ES = 0.685, 95% CI of difference = 3.1 to
26.2 reps). These differences manifested only
in total reps; there were no differences in reps
between conditions for any specific set for
the squats (p = 0.366), or bench press for that
matter (p = 0.939).
Interpretation
What we try to do in our interpretations is
give you a better understanding of a study
than you can get just from reading it. However, this interpretation doesn’t have a “gotcha”
like our interpretations sometimes do. There
isn’t a statistical nuance, methodological
caveat, error, or unnoticed confounder that
muddies the waters. While this study paints a
clear picture, it sits astride multiple murky areas. The longest peer review back-and-forths
I’ve had with Dr. Trexler were related to the
effectiveness of carbohydrates for enhancing
lifting performance and the effectiveness of
carbohydrate mouth rinsing for resistance
training. That’s not by chance; these are areas
where the data is conflicting study-to-study,
and the mechanisms aren’t fully understood.
This study tackles both of those topics and,
on top of that, it also delves into the elusive
nature of fatigue. So, to fully understand this
study, we have to unpack the surrounding
context of these areas. Before I do that, let’s
go over the findings in isolation.
This study was well-designed and analyzed,
and subsequently, the findings were clearcut. When doing high-volume, high-effort
muscular endurance training with partially
glycogen-depleted muscles, carb mouth rinsing may rescue performance to some extent.
35
Notice I said rescue and not improve. The fact
that bench press reps weren’t significantly
different between conditions indicates even
when really pushing the limits of realistic
volumes for a single exercise, a carb mouth
rinse might not improve performance much
without local glycogen depletion (as there
was in the lower body). Two more conditions
– another carb mouth rinse and another placebo – without glycogen depletion the night
prior would be needed to assess if carb mouth
rinsing actually improves performance, rather than just rescuing it from glycogen depletion. Admittedly, you can’t placebo-control a
cycling session. So, even with this design, we
can’t determine whether glycogen depletion
or negative expectancy impacted the next
day’s performance, but from a design standpoint, that’s what it would take to differentiate rescuing performance from improving it.
That said, much of the carb mouth rinsing literature is on non-glycogen-depleted subjects,
so we can look to those studies and related
research to put these findings into context.
In a previous review by Dr. Zourdos in Volume 2 on a carb mouth rinsing study that
appeared to improve volume performance
(4; MASS Review), Mike discussed the
broad state of the research up to that point
(in 2018). I’ve included Table 2 from his review so you can see that only a minority of
research at that time showed the efficacy of
carb mouth rinsing for enhancing lifting volume. Since his review, I’m aware of another study that failed to find an effect of carb
mouth rinsing on volume performed during
a moderate-load, high-volume, repetitions to
failure upper body session (5), and also a fol-
low up study by Clarke in 2017 where carb
mouth rinsing did improve reps to failure on
moderate-load bench and squat (6). Nonetheless, the research remains mixed, with a minority of studies showing an effect for carb
mouth rinsing. Importantly, I am just discussing volume outcomes and not strength,
because the literature has consistently shown
no significant effect of carb mouth rinsing on
maximal strength (7, 8, 9), even in a state of
fatigue (10). If there’s any hope for carbohydrate mouth rinsing to enhance lifting performance, it’s for enhancing volume, but even
then the effects are inconsistent.
The temptation when looking at this data set
is to dismiss the entire concept of carbohy-
LITERATURE HAS
CONSISTENTLY SHOWN NO
SIGNIFICANT EFFECT OF
CARB MOUTH RINSING ON
MAXIMAL STRENGTH EVEN
IN A STATE OF FATIGUE. IF
THERE’S ANY HOPE FOR
CARBOHYDRATE MOUTH
RINSING TO ENHANCE
LIFTING PERFORMANCE, IT’S
FOR ENHANCING VOLUME.
36
drate mouth rinsing for resistance training
because of these inconsistencies. It’s natural
to seek a binary “does it work or not?” conclusion, but it’s an urge best suppressed as
a pattern emerges when you look for similarities in the studies where a positive effect
of mouth rinsing was observed. In a study by
Decimoni and colleagues, a long-duration,
high-volume, high-rep protocol to failure
was used after an eight-hour overnight fast
(4). Similarly, Bazzuchi and colleagues had
their participants perform 30-rep sets after an
eight-hour overnight fast (3). Finally, the follow-up study by Clarke in 2017 observed an
improvement in repetitions to failure in the
squat and bench press at 60% of 1RM after
an 11-hour fast (6). Overall, we see that not
only is high volume, high effort, glycolytic
training needed to observe a positive effect of
mouth rinsing, but also a degree of carbohydrate (and energy) restriction. After an over-
night fast you can expect a reduction in liver
glycogen and possibly lower blood glucose.
The present study simply takes that concept
further, specifically depleting the muscle gly-
NOT ONLY IS HIGH VOLUME,
HIGH EFFORT, GLYCOLYTIC
TRAINING NEEDED TO
OBSERVE A POSITIVE EFFECT
OF MOUTH RINSING,
BUT ALSO A DEGREE OF
CARBOHYDRATE (AND
ENERGY) RESTRICTION.
37
cogen needed for the training session beforehand, and pushing even higher volumes with
higher-repetition sets to failure.
While the present study is the first to use this
design in resistance training, Kasper and colleagues used a similar design for high-intensity interval running (11). They depleted the
participants’ glycogen the night prior to testing with a high-intensity interval running session, then the next morning they performed
a further 45 minutes of steady state running
immediately prior to a high-intensity interval
running test to volitional exhaustion, during
which the subjects had carb or placebo mouth
rinses every four minutes. Like the present
study, during the carb mouth rinse condition, a greater (although not quite reaching
the threshold of statistical significance at p
= 0.06) volume of running was completed
during the mouth rinse condition (52 ± 23 vs.
36 ± 22 min).
LOW GLYCOGEN LEVELS
MAY NOT ONLY EXERT
LOCAL FATIGUE IN
MUSCLE, BUT ALSO SEEM
TO TRIGGER CENTRAL
FATIGUE THAT REDUCES
EXERCISE CAPACITY.
Arguably the most interesting aspect of the
carbohydrate mouth rinsing literature is how
it highlights the blurred line between peripheral and central fatigue. If the only limiting
factor for glycolytic performance was that
lower glycogen levels meant fewer muscle
fibers could come to the party, and those who
did come couldn’t contribute as long, a carbohydrate mouth rinse wouldn’t be effective
in a glycogen-reduced state. Thus, low glycogen levels may not only exert local fatigue
in muscle, but also seem to trigger central fatigue that reduces exercise capacity.
This hypothesis is difficult to study, and even
more difficult to study in humans, but a fascinating rodent study suggests that this is exactly what happens. Williams and colleagues
depleted glycogen in rats by 45% and observed how long they could run on a treadmill
in comparison to rats with high glycogen levels, and also observed how surgically removed
muscle from rats in both groups responded to
electrical stimulation (12). The rats with higher glycogen levels ran five times longer (167
± 23 vs. 35 ± 7 min); however, the surgically
removed muscles produced similar forces and
muscle fatigue patterns in both groups. This
is not to say that glycogen depletion doesn’t
have local effects on muscular performance.
Indeed it does, and in contrast to the findings
of Williams above, most studies don’t show
that they can be completely dissociated, as
glycogen depleted muscle often does produce
less force when isolated (13). Rather, it’s important to understand that glycogen depletion
not only induces fatigue locally, but may also
trigger central fatigue, both of which can contribute to reductions in performance.
38
Much like being in a state of low carbohydrate availability triggers central fatigue, it
is theorized that oral carbohydrate sensing
mechanisms in the mouth activate the reward
and motor control centers of the brain (14),
perhaps doing the opposite (e.g. reducing
central fatigue). However, the central fatigue
effects induced by glycogen depletion and
the central stimulus provided by carbohydrate mouth rinsing seem to be much more
pronounced for endurance rather than resistance exercise. For example, you may have
noticed the five-fold difference in time to exhaustion in glycogen-depleted mice, and you
may have also noticed the near 50% improvement in sprint interval time to exhaustion in
the Kasper study that used the same design
as the present study, but on running (11). In
comparison, the present study had only a 16%
difference in squat reps performed between
conditions. Notably, the data on mouth rinsing in general is much stronger for endurance
training. A recent meta analysis of 13 carb
mouth rinsing endurance studies found support for improvements in aerobic power (2),
which contrasts the few, condition-specific
carb mouth rinsing studies which observed
improvements in lifting performance. Moreso, actual carbohydrate ingestion also shows
a similar pattern. While a 2016 meta analysis
of 16 studies reported improvements in cycling performance due to carbohydrate supplementation (15), an excellent recent review
by Cholewa and colleagues (16) was titled
“Carbohydrate restriction: Friend or foe of
resistance-based exercise performance?” The
title alone suggests that carbohydrate as lifting aid is disputed, and in the conclusion the
authors state “Research examining the effects
of varying levels of carbohydrate restriction
has produced conflicting results. From this
body of research, it appears that low glycogen or carbohydrate availability does not
negatively affect acute resistance exercise
performance when the volume (<8 sets) and
duration (<45 min) of exercise is low and the
intensity is high (>85% 1 RM).”
When we put this all together, and we consider that the effects of local glycogen depletion
are not the only limiting factor in fatigue, the
murkiness starts to become clearer. To me,
it’s intuitive that if carbs are more likely to
improve lifting performance during high volume glycolytic training to failure in a state
of low carbohydrate availability, and that if
low carbohydrate availability is both a local
mechanism of fatigue and a trigger for central fatigue, that we should only expect carb
mouth rinsing to improve performance under
similar conditions. Coming back to the present
study, this means that its main strength is its
main limitation. This study has clarified that
a carb mouth rinse will have a notable effect
on lifting performance, if that lifting starts to
share similarities with endurance training, and
if you go into that session in a state of low carbohydrate availability. However, most MASS
readers won’t fast for 8-11 hours or find themselves severely muscle glycogen-depleted
before then doing a high-volume, high-rep,
high-effort, low-load lifting session.
Next Steps
This was a great “proof of concept” study. It
pushed the limits of ecological validity to see
where this strategy might come into play. Now
that we know the combination of high-volume,
39
APPLICATION AND TAKEAWAYS
Carb mouth rinsing improves performance via central mechanisms. Low-glycogen
levels not only cause local fatigue, but also trigger central fatigue which contributes to
reduced performance. This is more pronounced the more lifting resembles endurance
training. In a state of low carbohydrate availability, if you have to perform highrep, fatiguing training, and you can’t consume carbs for whatever reason, swishing
Gatorade in your mouth and spitting it out before each set may aid performance.
high-effort, high-rep training in a glycogen-depleted state is required for mouth rinsing to
prove fruitful, I would like to see it tested in applied settings. I could see mouth rinsing having
potential for CrossFit, certain events in Strongman/woman and Highland Games, and during
bodybuilding contest prep. Lower carb diets are
common in the CrossFit community, this style
of training is the bread and butter of the sport,
and getting in a lot of food prior to these challenging events may cause gastrointestinal (GI)
distress. Events like farmer’s walk for max distance are sometimes in Strongman/woman and
Highland Games, Strongman/woman is weight
class restricted, and having a lightweight class is
more common in Highland Games these days.
If part of the process of making weight includes
carbohydrate restriction, and there isn’t enough
time to properly refuel, or an athlete experiences GI distress, mouth rinsing may be the best
option. Finally, physique athletes in contest
prep are often on low-energy, low-carb diets,
have to perform cardio the day prior to lower
body hypertrophy training, and can’t consume
much carbohydrate, as they must maintain an
energy deficit. Each of these conditions could
be replicated with a similar design as the present study to see if carb mouth rinsing could help
in these situations.
40
References
1. Durkin M, Akeroyd H, Holliday A. Carbohydrate mouth rinse improves resistance
exercise capacity in the glycogen-lowered state. Appl Physiol Nutr Metab. 2020 Jul 29.
Epub ahead of print.
2. Brietzke C, Franco-Alvarenga PE, Coelho-Júnior HJ, Silveira R, Asano RY, Pires FO.
Effects of Carbohydrate Mouth Rinse on Cycling Time Trial Performance: A Systematic
Review and Meta-Analysis. Sports Med. 2019 Jan;49(1):57-66.
3. Bazzucchi I, Patrizio F, Felici F, Nicolò A, Sacchetti M. Carbohydrate Mouth Rinsing:
Improved Neuromuscular Performance During Isokinetic Fatiguing Exercise. Int J Sports
Physiol Perform. 2017 Sep;12(8):1031-1038.
4. Decimoni LS, Curty VM, Almeida L, Koch AJ, Willardson JM, Machado M.
Carbohydrate mouth rinsing improves resistance training session performance.
International Journal of Sports Science & Coaching. 2018;13(5):804-809.
5. Krings BM, Shepherd BD, Waldman HS, McAllister MJ, Smith JW. Effects of
Carbohydrate Mouth Rinsing on Upper Body Resistance Exercise Performance. Int J
Sport Nutr Exerc Metab. 2019 Sep 27:1-6.
6. Clarke ND, Hammond S, Kornilios E, Mundy PD. Carbohydrate mouth rinse improves
morning high-intensity exercise performance. Eur J Sport Sci. 2017 Sep;17(8):955-963.
7. Painelli VS, Roschel H, Gualano B, Del-Favero S, Benatti FB, Ugrinowitsch C, Tricoli
V, Lancha AH Jr. The effect of carbohydrate mouth rinse on maximal strength and
strength endurance. Eur J Appl Physiol. 2011 Sep;111(9):2381-6.
8. Clarke ND, Kornilios E, Richardson DL. Carbohydrate and Caffeine Mouth Rinses Do
Not Affect Maximum Strength and Muscular Endurance Performance. J Strength Cond
Res. 2015 Oct;29(10):2926-31.
9. Dunkin JE, Phillips SM. The Effect of a Carbohydrate Mouth Rinse on Upper-Body
Muscular Strength and Endurance. J Strength Cond Res. 2017 Jul;31(7):1948-1953.
10. Black CD, Schubert DJ, Szczyglowski MK, Wren JD. Carbohydrate Mouth Rinsing Does
Not Prevent the Decline in Maximal Strength After Fatiguing Exercise. J Strength Cond
Res. 2018 Sep;32(9):2466-2473.
11. Kasper AM, Cocking S, Cockayne M, Barnard M, Tench J, Parker L, McAndrew J,
Langan-Evans C, Close GL, Morton JP. Carbohydrate mouth rinse and caffeine improves
high-intensity interval running capacity when carbohydrate restricted. Eur J Sport Sci.
2016 Aug;16(5):560-8.
41
12. Williams JH, Batts TW, Lees S. Reduced muscle glycogen differentially affects exercise
performance and muscle fatigue. ISRN Physiology. 2012 Dec 3;2013.
13. Ørtenblad N, Westerblad H, Nielsen J. Muscle glycogen stores and fatigue. J Physiol.
2013;591(18):4405-4413.
14. Chambers ES, Bridge MW, Jones DA. Carbohydrate sensing in the human mouth: effects
on exercise performance and brain activity. J Physiol. 2009;587(Pt 8):1779-1794.
15. Pöchmüller M, Schwingshackl L, Colombani PC, Hoffmann G. A systematic review
and meta-analysis of carbohydrate benefits associated with randomized controlled
competition-based performance trials. J Int Soc Sports Nutr. 2016 Jul 11;13:27.
16. Cholewa JM, Newmire DE, Zanchi NE. Carbohydrate restriction: Friend or foe of
resistance-based exercise performance? Nutrition. 2019 Apr;60:136-146.
█
42
Study Reviewed: The Effects of Diet Composition and Chronic Obesity on Muscle Growth
and Function. de Sousa et al. (2020)
Does Getting Lean Make Your Next
Bulk More Effective?
BY ERIC TREXLER
It’s increasingly common to hear that excessive body fat can
impede hypertrophy during a bulk, primarily due to reduced
insulin sensitivity. This article aims to review a recent rodent study
related to this concept, then explore the evidence supporting and
contradicting the idea of getting lean to potentiate muscle gains.
43
KEY POINTS
1. The presently reviewed study (1) found that obesity doesn’t necessarily impair
hypertrophy in mice, and leaner mice do not necessarily make better gains in
response to muscular loading.
2. It’s become common to suggest that getting leaner will potentiate subsequent
hypertrophy by improving one’s p-ratio via enhanced insulin sensitivity, but the
evidence for this claim is pretty flimsy.
3. The most muscular drug-free lifters and athletes in the world tend to have relatively
high body-fat levels. Longitudinal studies in strong people who lift find that obese,
insulin-resistant lifters make gains that are similar to lean, insulin-sensitive lifters, and
weight loss typically has neutral or negative effects on p-ratios during weight regain.
4. There are plenty of good reasons to do a fat loss phase, but potentiating hypertrophy
doesn’t seem to be one of them.
I
n the evidence-based fitness world, I’m
starting to hear more and more people
suggesting that excess body fat can impede hypertrophy during a bulk. The idea
is that excess body fat can impair muscle
insulin sensitivity, which impedes nutrient
delivery to the muscle, and therefore causes
some friction in the muscle-building process.
As the theory goes, poor insulin sensitivity
causes a drop in an individual’s “p-ratio,” or
the proportion of weight change that is due
to changes in protein reserves. In more tangible terms, a high p-ratio during weight loss
means a proportionally large reduction in
lean mass, and a high p-ratio during weight
gain means a proportionally large increase in
lean mass. As a means of circumventing this
potential concern of a skewed p-ratio due to
reduced insulin sensitivity, I’m hearing more
and more people suggesting that you should
cut to a lower body-fat percentage before you
bulk. The strategy is predicated on the idea
that cutting to lower body-fat levels will en-
hance muscle insulin sensitivity, and actually
potentiate muscle growth in the subsequent
mass-gaining phase. This article aims to review a recent rodent study that addresses this
concept head-on (1), with results suggesting
that excess fat mass does not impair hypertrophy in response to functional overload. While
rodent research gives us an exceptional level
of control and allows us to explore some concepts that would otherwise be difficult to experimentally study in humans, we rarely focus on non-human research models in MASS
due to generalizability issues. So, in this article I will discuss the results of the rodent
study, but mostly use it as a springboard for
a concept review on the idea that excess fat
mass would impair hypertrophy. In doing so,
I’ll discuss where this idea came from, then
weigh the human evidence supporting and
contradicting the idea, ultimately leading to
very practical takeaways. So, if you’re thinking about scrolling by because you’re not
focused on getting your pet mouse jacked, I
44
would encourage you to read on for some really useful and applicable conclusions.
Purpose and Hypotheses
Purpose
The purpose of the presently reviewed study
(1) was “to examine the effect of a long duration (28 weeks) of diet-induced obesity on
muscle mass and function, as well as the ability of muscle to respond to increased external
loading.” I’ll note that we’re talking about
mice here, so 28 “mouse weeks” represent
a really long time in terms of translating to
human physiology. Just to set some frame of
reference using rats as an example, one “rat
day” equates to approximately 35 “human
days” (2).
Hypotheses
The researchers hypothesized that “diets with
elevated fat content would induce obesity
and insulin resistance, leading to a decrease
in muscle mass and an attenuated growth response to increased external loading in adult
male mice.”
Subjects and Methods
Subjects
This study utilized a particular genetic line
of mice known as C57BL6 mice, which were
great for this study because they tend to be
susceptible to diet-induced obesity. In fact,
C57BL6 males are particularly susceptible,
so the study utilized males only. I’m no rodent expert, but it seems like this is a nice
mouse strain for studying obesity; when
presented a high-fat, energy-dense diet, it
tends to develop obesity, hyperinsulinemia,
hyperglycemia, and hypertension, whereas
these issues fail to develop when they’re fed
a more standard chow diet (3). Most importantly, this allows the researchers to induce
a pretty human-like state of metabolic syndrome without having to do anything too
drastic, like selecting a mouse line that fails
to produce leptin or has no leptin receptors.
Methods
When the mice were 8 weeks old, they were
randomly assigned to one of five diets: standard, low-fat, high-fat, high-sucrose, or Western. I won’t dwell too much on the exact diet
composition, as we’re primarily interested
in what occurs after the fat gain process, but
the general idea is that the diets have varying
macronutrient ratios and energy densities. The
high-fat diet and Western diet had the highest
energy densities, the standard chow diet had
the lowest energy density, and the low-fat and
high-sucrose diets fell in-between.
The total diet duration was 28 weeks. Toward
the end of the intervention (starting around
week 24), a variety of tests were carried out to
assess outcomes related to body composition,
muscle protein synthesis, muscle contractile
function, and glycemic control. About 25
weeks in, half of the mice underwent surgery
to induce functional overload of the plantaris
muscle. Basically, they surgically removed
the soleus and gastrocnemius muscles, which
induces extra loading on the plantaris muscle. This extra loading allows us to observe
the hypertrophic response in the animals that
underwent surgery. With this experimental
approach, the researchers were able to observe how varying combinations of adiposity
45
and diet influenced hypertrophic responses in
the overload period following surgery.
Findings
The diets had differential effects on fat gain
during the first 24 weeks of the intervention.
Fat mass was highest in the mice on the high-fat
diet (25.33 ± 0.98 g) and Western diet (22.29
± 2.78 g), and lower in the mice consuming
a standard diet (16.52 ± 2.38 g), low-fat diet
(15.95 ± 2.38 g), or high-sucrose diet (15.70
± 2.10 g). The groups had similar amounts of
lean mass and fluid content (Figure 1).
The glycemic control results were pretty interesting. After nine weeks of feeding, the Western diet and high-fat diet led to impaired glycemic control in comparison to the standard
chow diet. The researchers looked at several
aspects of glycemic control, but Figure 2 presents the glucose area under the curve during a
glucose tolerance test. For someone with great
glycemic control and high insulin sensitivity,
the area under the curve would be low; for
someone with poor glycemic control and insulin resistance, the area under the curve would
be high. The interesting part of these results
is that the Western diet group started looking
more similar to the standard chow group when
the test was repeated after 21 weeks of feeding (Figure 2). This might relate to the rate of
weight gain across the entire study; after week
9, the Western and high-fat groups were pretty
similar in weight, and much heavier than the
chow group. By week 22, the chow group had
continued gaining weight (you can see that the
standard chow group’s area under the curve
value increased substantially from the first
glucose tolerance test to the second), and the
weight gap between the high-fat group and the
Western group grew.
Diet-induced obesity did not significantly impact muscle mass or function. After 24 weeks
of feeding, the groups did not significantly
differ in terms of maximal isometric torque of
the plantarflexors or dorsiflexors. As Figure 1
indicates, the groups did not significantly differ in terms of lean body mass. In addition, the
researchers looked at resting protein synthesis
levels, the mass of a bunch of different muscles, and the cross-sectional area of muscle
fibers from the gastrocnemius and plantaris.
In the absence of functional overloading, the
diets did not lead to significant between-group
differences in terms of resting protein synthesis, muscle masses, or fiber cross-sectional
area values. Overall, the data did not indicate
that the diets, or diet-induced obesity, significantly impacted these outcomes.
Plantaris growth in response to functional
overload was expressed as a percentage, rel-
46
ative to the respective dietary control (that is,
growth in the high-sucrose + overload group
was expressed relative to the growth observed
in the high-sucrose group without overload).
After 14 days of functional overloading,
plantaris growth in the high-fat (132%) and
Western (133%) groups were significantly
lower than the standard chow group (156%).
However, after 30 days, the Western group
(165%) had actually experienced slightly
more relative growth than the standard chow
group (161%), whereas values in the high-fat
group remained lower (134%). All groups
had pretty similar increases in protein synthesis rates, both at day 14 and day 30. Plantaris
growth values after 14 and 30 days are presented in Figure 3.
Interpretation
There are a few ways to interpret the findings of the presently reviewed study (1). The
most straightforward interpretation is pretty
simple: simply developing obesity did not
impair hypertrophy over the 30-day overload
period, as the Western diet group had the second-largest magnitude of plantaris growth.
However, due to some complicating factors,
it’d be disingenuous to suggest that this study
irrefutably disproves the concept that obesity-induced reductions in insulin sensitivity
lead to suboptimal hypertrophy conditions.
For example, the Western diet group had a
remarkable improvement in insulin sensitivity from the 10-week point to the 22-week
point, despite remaining obese and eating the
same diet. That complicates things, because
one could argue that the theory kind of held
up; the high-fat group was the only group
with dramatically worse insulin sensitivity
by the time the functional overload period
occurred, and they had an impaired hypertrophy response. You could certainly argue
that the specific food sources or macronutrient intakes of the high-fat diet were hindering
hypertrophy in the high-fat diet group, but
47
you could also argue that it was their insulin resistance that was getting in the way, and
the study design doesn’t allow us to definitively determine which interpretation is more
correct. The within-group time course of hypertrophy adaptations also raises some questions. Why did the low-fat group actually sustain some atrophy from the 14-day overload
time point to the 30-day time point? Why did
the Western diet group seem to have a delayed response, with underwhelming values
at 14 days, but remarkable catch-up growth
by day 30? Why did the high-sucrose group
have pretty modest hypertrophy at day 14,
then skyrocket to the front of the pack at day
30? Frankly, I don’t have answers to those
questions. You might be thinking this is some
flimsy evidence to “debunk” the concept that
losing fat will lead to potentiated hypertrophy, and that it’s questionable to generalize
findings from resistance-trained mice to resistance-trained humans. But where did this
concept come from, anyway?
Surprisingly, the evidence supporting this
theoretical link between body fat, insulin
sensitivity, and hypertrophy potential rests
on equally shaky ground. As far as I can tell,
a review paper by Forbes (4) is where it all
began. The paper included a figure, which
pointed out that the p-ratio (in this case, the
proportion of weight gained as lean mass)
seemed to be higher for leaner samples, and
lower for samples with higher body-fat levels
during purposeful weight gain. So, the leaner samples tended to gain a larger proportion
of weight as lean mass. You might have also
seen a more recent article by Forbes cited
when discussing this topic (5), which reprinted the same figure without any additions or
modification. This figure includes five data
points representing a total of 44 participants,
and it’s honestly pretty hard to track down
exactly which studies are represented in the
figure. However, it appears that the sample is
largely made up of anorexia nervosa patients,
lactating women, and people who recently
48
underwent “prolonged total starvation” to
induce dramatic weight loss (as in, 25-67kg
of weight loss). As far as I can tell, none of
the participants were undergoing resistance
training, and the overfeeding protocols were
not standardized in any way, with variable
magnitudes, durations, macronutrient profiles, and so on. If we’re trying to draw inferences about the topic at hand, I think I might
actually feel more comfortable generalizing
results from a mouse study with muscular
overload and a standardized intervention than
the human data presented in the Forbes figure, which is commonly leaned on.
It would be inaccurate to suggest that the supporting evidence ends there, however. Kevin
Hall revisited Forbes’ theory in a 2007 paper
(6), in which he acknowledged that the Forbes
data relies heavily on overfeeding evidence
from recovering anorexia patients, which
probably has poor generalizability to other
populations. There appears to be a “threshold”
effect in anorexia recovery; patients who present with especially low BMIs (in this study,
≤16.5) regain more lean mass in the initial recovery period than patients who present with
a BMI >16.5 (7). While I don’t necessarily
expect that to be a universally true cutoff that
generalizes to all samples, I would speculate
that this general relationship is a physiologically necessary adaptation to prioritize the reversal of extreme levels of fat-free mass depletion when severely low BMIs are achieved,
which can be catastrophically dangerous (especially the loss of organ mass). I mentioned
that Hall highlighted this large contribution of
anorexia recovery data to the Forbes model,
but Hall actually acknowledged that a review-
er brought this to his attention during the peer
review process. I think this highlights the fact
that the underlying context of the data fueling
the Forbes model seems to frequently get lost
in translation (like I said, it’s presented in a
way that makes it a little tedious to track down
where the data actually came from). It seems
that few people in the evidence-based fitness
space are aware that they’re hearing nutrition
recommendations for lifters that are based on
lean mass changes in a combination of recovering anorexia nervosa patients and people who
are rebounding from prolonged total starvation to induce up to 67kg of weight loss, none
of whom were lifting weights. Anyway, Hall
put his own spin on Forbes’ idea, omitted the
data from anorexia nervosa studies, crunched
some numbers, and concluded that the general idea holds up: overfeeding lean people still
seemed to result in a more favorable p-ratio in
comparison to overfeeding people with higher
body-fat levels.
However, there are still two huge issues to
discuss before taking this finding as a generalizable fact and using it to suggest that we
should cut before we bulk. First, these data
are entirely cross-sectional in nature. None of
the studies in the Hall review, or the Forbes
review, suggest that getting leaner will improve your p-ratio when you transition to a
bulk. They suggest that people who are lean
tend to have relatively leaner gains, which
could theoretically be an innate characteristic
that contributes to these people being lean in
the first place. The inverse is true for people
with higher body-fat; if they seem to gain a
higher proportion of mass as fat, that might
be a contributing factor to their high body-fat
49
level at the time of observation. The second
issue is that the p-ratio goes both ways: these
models put forward by Forbes and Hall suggest that leaner people gain more lean mass
when overfeeding, but lose more lean mass
when underfeeding. If you’re using these
models to suggest that a person should cut to
a lean body-fat level to potentiate their hypertrophy during the next bulk, I’m not sure how
you don’t automatically accept that the leaner
they get, the more lean mass they’ll lose. If
you’re assuming that this model generalizes
to longitudinal situations, then you’d have
to accept that the only way to cut down and
get to the really, really ideal bulking p-ratios
is to accept the really, really large losses in
lean mass along the way. In essence, you’re
inducing lean mass loss to increase your likelihood of regaining lean mass. I’m not necessarily saying that’s how physiology works,
but that’s how the model works.
So, we’ve got some theoretical models based
on cross-sectional findings in people who
don’t lift, and a longitudinal study in mice
who do. If you’re wondering if there’s an easier way to address this question, the answer
is yes. While this conversation typically revolves around theoretical models and mechanistic insulin-related rationale, why don’t we
take a look at actual changes that occur when
lifters lift.
If we are assuming that this concept (high
body-fat impairs hypertrophy via insulin
resistance) is true, it seems like we should
eventually observe that high levels of bodyfat should at least attenuate the accretion of
lean mass, if not induce atrophy. In reality,
we observe very contrary findings. Fat-free
mass index tends to positively correlate with
body-fat percentage, and cross-sectional assessments of American football teams indicate that higher fat-free mass index values
are generally observed in the position groups
with higher body-fat percentages (8). Similarly, Abe et al (9) sought to make observations about the upper limits of human muscularity, and reported individual-level data for
their 10 most muscular participants. 8 of the
10 had body-fat percentages over 20%, with
the highest being 34.4%. Sumo wrestlers
have the highest fat-free mass index values
I’ve ever seen in published literature (10),
and the sport isn’t known for having shredded athletes. The point is, if adiposity has
an inhibitory effect on muscle hypertrophy,
it seems intuitive to suggest that lean mass
would be hard to come by at high body-fat
percentages. However, when we look for
the drug-free lifters and athletes carrying the
most lean body mass, they’re almost invariably up at 20% body-fat or higher, and the
large amounts of lean mass we see at these
higher body-fat percentages go well beyond
the magnitude of differences that could be
theoretically attributed to the fat-free component of adipose tissue (11).
To be fair, that justification relies on
cross-sectional data, which has shortcomings. Fortunately, we can lean on longitudinal data as well. The great thing about American football, aside from being an all-around
enjoyable sport, is that it allows us to observe
training responses of numerous athletes within a wide range of body-fat levels who want
to add some muscle. When we look at longitudinal data within the same team, we’re
50
also observing people training in the same
environment with the same equipment and
the same coaches and the same motivators,
which sweetens the deal even more. Stodden
et al (12) examined training responses within
American football players on the same team,
with players classified as “skill,” “big skill,”
or “linemen.” Looking at training responses
in first-year players, the skill group showed
up with a baseline body-fat percentage of
6.95% and gained 3.2kg of lean mass. The
big skill group showed up at 11.6% body-fat
and gained 3.2kg of lean mass in year 1. The
linemen showed up at 21.1% body-fat and
gained 4.6kg of lean mass. Further, these lean
mass gains can’t be attributed to a greater emphasis on overall weight gain in the linemen
group; the skill group gained 3.14kg of total
mass, the big skill group gained 2.50kg, and
the linemen gained 3.12kg. So, the linemen
had not only the largest lean mass gains, but
also the most favorable p-ratio.
Jacobson et al (13) also reported longitudinal changes in linemen and skill players in
their first year of collegiate American football. The skill players showed up at 8.4%
body-fat, and in year 1 they gained 6kg of
fat-free mass and about 0.1kg of fat mass.
The linemen showed up at 22.5% body-fat;
in year 1 they gained 6.5kg of fat-free mass
and lost 4kg of fat mass. Again, the linemen
had larger absolute gains in fat-free mass,
and a more favorable p-ratio. Some might
argue that the linemen only had such lean
gains because their calorie intake was low
enough to support a concurrent loss of fat
mass; I would counter by pointing out that
such a scenario would theoretically put them
in less favorable conditions to add muscle,
yet they still added more fat-free mass than
the skill players. Plus, the specific hypothesis
we’re discussing is that having higher body
fat impairs muscle gains or unfavorably impacts p-ratios, so gaining more muscle while
losing more fat mass seems to be doubly-incompatible with the concept. When I was in
graduate school, my lab also published some
research reporting longitudinal body composition changes in collegiate football players,
divided into linemen and non-linemen subgroups (14). One of the cool things about our
study is that we had multiple-year data on a
subsample of 13 participants. While this subsample was too small to allow for statistical
comparisons between position groups, it provides evidence over a longer timescale than
single-year studies. Over a four-year span,
the linemen (who had higher initial body-fat
percentages) gained more total weight (8.5 ±
5.4 versus 5.4 ± 2.7 kg) and more lean mass
(6.2 ± 3.2 and 3.1 ± 2.4 kg) than the non-linemen, with a larger percentage of their weight
gain coming from lean mass. Of course we’d
never make definitive conclusions based on
such a small subsample of players, but this
is just one of multiple instances in which the
concept of impaired hypertrophy via higher
body-fat percentage doesn’t seem to play out
in real-world scenarios.
Given that the concept in question is theoretically linked to insulin sensitivity, one
might speculate that college football linemen have obesity in the absence of impaired
insulin sensitivity, kind of like the Western
diet group did by the end of the presently reviewed study. However, research (15) indi-
51
cates that body-fat percentage is significantly
associated with insulin resistance within a
team of high-level collegiate football players (p < 0.0001), with many of the linemen
having both obesity (defined as body-fat
percentage ≥ 25%) and insulin resistance
(defined as a quantitative insulin sensitivity
check index value < 0.33). Of course, there
are shortcomings related to relying exclusively on data from American football players. This is a unique population that doesn’t
necessarily represent the broader population
of all people who lift. You might also argue that the sport requires different physical
characteristics and capabilities from different
position groups, which might contribute to
linemen and non-linemen placing differing
emphasis on key aspects of their training and
nutrition. I wouldn’t necessarily suggest that
college football data is perfectly suited to answer our questions about the topic at hand,
but for making inferences about hypertrophy
in lifters, this data is far more suitable than
the models by Forbes and Hall. That doesn’t
mean the models are bad (Forbes and Hall are
remarkably accomplished scientists), it just
means the models were never made for “us”
(lifters) to use for longitudinal forecasting
in our bulking and cutting cycles. When we
shift our focus instead to the American football literature, we’ve got strong people lifting
to get big, the observed body fat range among
players covers the overwhelming majority of
lifters, and we’ve got solid longitudinal body
composition data in a population where the
relationship between body-fat percentage and
insulin resistance has been empirically established (15). Overall, the data don’t seem to
indicate that football players with higher ini-
tial body-fat percentages have more trouble
gaining lean mass, nor do they suggest that
they tend to gain a disproportionately large
percentage of weight as fat mass rather than
lean mass. I’m sure there are some samples
of football players out there where the opposite may be observed, whether they’re published or not, but the presence of numerous
counterexamples casts doubt on the idea that
lower baseline body-fat is a reliable predictor
of potentiated hypertrophy in a subsequent
period of resistance training.
At this point, the concept that you can potentiate hypertrophy phases with prior fat
loss doesn’t seem to be compatible with
cross-sectional observations that body-fat
percentage and fat-free mass index are positively correlated in people who lift, nor does
it seem to be compatible with the gains made
by football players with varying levels of adiposity and insulin sensitivity. But let’s take
our analysis a step further and incorporate a
temporal component; after all, the purported
benefits come from specifically cutting fat
before a muscle gaining phase, in that order.
So, do people have exceptional lean mass
gains following a cut?
No. When people discuss the pros and cons
of yo-yo dieting, you rarely hear “annoyingly
excessive amounts of muscle gain” cited as a
drawback. In many circumstances, the exact
opposite is true, and we observe preferential
regain of fat when someone transitions from a
weight loss phase to a weight gain phase, despite the fact that preceding weight loss phases
are likely to induce either neutral or beneficial
effects on insulin sensitivity. Back in graduate
school, our lab ran a study looking at post-com-
52
petition weight regain in competitive physique
athletes (16). After accounting for a little rebound in glycogen and water weight, the gains
observed in the immediate post-competition
were largely fat-driven and represented a pretty unfavorable p-ratio. If getting lean and being
insulin-sensitive truly potentiates hypertrophy,
these lifters should’ve been primed for some
seriously lean gains. Of course, we certainly
weren’t the first folks to notice this preferential fat regain following a fat loss phase. As
reviewed by Dulloo et al (17), several research
studies specifically observing weight gain after
weight loss (as opposed to cross-sectional responses to overfeeding) have documented that
fat is disproportionately regained in the initial
weight regain period, which is potentially related to some degree of lingering suppression
of energy expenditure that persists beyond the
active weight loss period. Fortunately, this
observation is not universal; as Dulloo and
colleagues point out, preferential fat regain is
typically observed after more extreme fat loss
attempts in which people either lose a lot of fat
mass (let’s say more than a third of their initial fat mass) or get extremely lean. I think this
review paper provides a fantastic and more
nuanced assessment of the p-ratio discussion.
They argue that, to some extent, p-ratios are an
intrinsic characteristic that varies from person
to person and is associated with their baseline
body-fat level, which generally lines up well
with the cross-sectional overfeeding literature.
However, they add that an individual’s p-ratio
is malleable, to some extent.
Of course, we can affect the relative proportion of weight gained as lean mass by adjusting our training stimulus, energy surplus, and
macronutrient intakes, but an individual’s
p-ratio can also be transiently influenced by
the loss of tissue. The loss of fat mass appears
to drive a reduction in energy expenditure
that favors fat regain, the loss of lean mass
appears to drive excessive hyperphagia (hunger) that favors lean mass restoration, and
these inputs seem to result in an unchanged
p-ratio after modest weight loss but a less
favorable p-ratio after more extreme weight
loss. It may seem like this theory contradicts
the previously cited research comparing lean
mass gains in anorexia patients with varying
baseline BMI levels (7), but that’s not quite
the case. Dullo’s argument suggests that the
restoration of fat mass and lean mass are influenced by a physiological “memory” of
initial amounts of fat mass and lean mass,
and that fat mass seems to be restored back
near its initial level at a similar or accelerated rate when compared to the restoration
of lean mass. In the anorexia recovery study,
the patients with BMIs ≤16.5 regained more
lean mass during recovery than patients with
BMIs >16.5, which may seem as if the leaner
people had more preferential regain of lean
mass. However, the actual changes in body
mass reflect a virtually complete restoration
of “typical” fat mass reserves, but restoration
of lean mass could still be viewed as relatively
incomplete at the time of post-treatment observation. After treatment, the patients with
baseline BMI ≤16.5 had effectively “caught
up” with the BMI >16.5 group in terms of fat
mass (12.75kg versus 12.06kg, respectively),
but still had less lean mass (36.62kg versus
38.64kg) at a comparable average height
(1.61m and 1.62m). As this example demonstrates, there’s a lot more to the story than
53
baseline fat mass and p-ratios; there are important contextual factors to consider when
evaluating the time course and completeness
of the restoration of various tissue types. The
general framework outlined by Dulloo et al
seems to be a more nuanced conceptualization of p-ratios during weight regain, and
gives us no reason to view fat loss as our ticket to potentiating subsequent hypertrophy.
Finally, I want to address one more line of
research that might be used to support the
theory that body-fat reduction would potentiate hypertrophy. As outlined in a very nice
review paper by Beals and colleagues (18),
there are several studies indicating that obesity can reduce the muscle protein synthetic
response to the ingestion of protein, potentially due to obesity-induced reductions in insulin sensitivity or increases in inflammation.
While these findings are fascinating, it’s important to keep a few caveats in mind. First of
all, while sedentary people with obesity may
have blunted protein synthesis responses to
a dose of protein, muscle protein breakdown
also tends to be lower in people with obesity
(19). As a result, we rarely see that this blunted response to protein feeding results in lower absolute lean mass values in obese individuals, and quite often find the opposite to be
true. In addition, the review only covers two
studies involving a resistance training stimulus (19, 20), which are the only two that I’m
aware of. One of those studies (19) found that
obese and non-obese individuals had similar
muscle protein synthetic responses to a bout
of resistance exercise, despite having significantly greater insulin resistance and significantly higher levels of C-reactive protein (a
biomarker used to assess inflammation). The
other study (20) found that the myofibrillar
protein synthesis response to protein alone
was similar in obese and non-obese individuals, which contrasts with the findings of some
previous studies. Further, the myofibrillar
protein synthesis response to resistance exercise was not only impaired, but totally blunted
in participants with obesity. For participants
with obesity, myofibrillar protein synthesis
rates following protein ingestion were virtually identical in their trained leg and their
untrained leg. However, the researchers
found no between-group differences related
to inflammation markers, and as noted previously, impaired insulin sensitivity doesn’t
seem to be reliably blunting hypertrophy in
the available human literature. While acute
muscle protein synthesis responses are not
THERE IS INSUFFICIENT
EVIDENCE TO SUGGEST
THAT LOSING WEIGHT
WILL ENHANCE
SUBSEQUENT
HYPERTROPHY BY
ENHANCING INSULIN
SENSITIVITY.
54
necessarily predictive of hypertrophy over
time (21), you’d still imagine some impact
of resistance training on protein synthesis
rates, given that individuals with obesity routinely achieve some degree of hypertrophy
after initiating a resistance training program
(19). While I hope future research will continue to investigate muscle protein synthesis
and breakdown responses to protein ingestion and resistance training in lean and obese
individuals, it seems premature to conclude
that higher body-fat will impair hypertrophy
in response to resistance training. In addition,
from a mechanistic perspective, this rationale
seems more applicable to totally sedentary
individuals than to individuals engaged in
exercise.
In summary, there is insufficient evidence to
suggest that losing weight will enhance subsequent hypertrophy by enhancing insulin
sensitivity. If we look at cross-sectional data,
THERE ARE PLENTY OF
GOOD REASONS TO
DO A FAT LOSS PHASE,
BUT POTENTIATING
HYPERTROPHY
DOESN’T APPEAR TO
BE ONE OF THEM.
the largest and most muscular drug-free athletes tend to have plenty of body-fat and impaired insulin sensitivity. If we use collegiate
American football as a model for longitudinal hypertrophy in lifters with varying levels
of body-fat and insulin sensitivity, the lifters
with high body-fat and lower insulin sensitivity seem to do just fine. If we look at longitudinal data on weight regain following weight
loss, p-ratios seem to be either unaffected or
unfavorably affected by the preceding weight
loss phase. If your long-term goals include a
combination of gaining more muscle and losing more fat, there are justifiable reasons to
take care of the fat loss part first. If you like
how your cardiometabolic health biomarkers look at a lower body-fat percentage, and
you want to get them there before you focus
on muscle gain, that makes sense. Similarly,
if you prefer the way you look, feel, or perform at a lower body-fat percentage, that’s
another great reason to cut prior to your bulk.
However, the commonly discussed idea that
losing body fat will potentiate future hypertrophy by enhancing insulin sensitivity and
optimizing your p-ratio appears to be poorly
supported and contradicts more relevant literature in people who lift.
Next Steps
It seems like this topic could be directly addressed by a pretty straightforward study that
(to my knowledge) has yet to be done. You
could recruit a group of resistance-trained
participants and do a matched-pairs design, in
which weight-stable participants are matched
up with someone who has similar body composition. One person in each pair does a fat-
55
APPLICATION AND TAKEAWAYS
When evaluating a concept that is supported by indirect evidence or theoretical
justification, it’s important to run through a checklist. What actual data formed the
basis for this idea? Are those data relevant to the circumstances in which they’re
being applied? If this idea is true, what real-world outcomes should we expect
to observe as a result? If the topic hasn’t been studied directly and intentionally,
are there any other lines of research that might have generated relevant and
generalizable evidence that we can utilize? When it comes to the commonly held
belief that cutting will potentiate subsequent hypertrophy by enhancing insulin
sensitivity, it appears that the idea was largely derived from cross-sectional data
obtained from studies with poor generalizability to lifters. Moreover, the idea
appears to be incompatible with observations about who seems to achieve the
most hypertrophy on the planet, how athletes of varying body-fat levels respond to
longitudinal resistance training, and the composition of tissue regained after weight
loss in longitudinal studies. After weighing the evidence for and against, it seems that
there are plenty of good reasons to do a fat loss phase, but potentiating hypertrophy
doesn’t appear to be one of them.
loss phase, then an 8-12 week bulk, and the
other just jumps straight into the 8-12 week
bulk without a prior fat loss phase. I would
hypothesize that the subjects who jump right
into the bulk would have similar or slightly
better hypertrophy results during the 8-12
week bulking period than the subjects who
did a weight loss phase prior to their bulk.
56
References
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Effects of Diet Composition and Chronic Obesity on Muscle Growth and Function. J
Appl Physiol. 2020 Nov 19; ePub ahead of print.
2. Sengupta P. The Laboratory Rat: Relating Its Age With Human’s. Int J Prev Med. 2013
Jun;4(6):624–30.
3. Lang P, Hasselwander S, Li H, Xia N. Effects of different diets used in diet-induced
obesity models on insulin resistance and vascular dysfunction in C57BL/6 mice. Sci Rep.
2019 20;9(1):19556.
4. Forbes GB. Lean body mass-body fat interrelationships in humans. Nutr Rev. 1987
Aug;45(8):225–31.
5. Forbes GB. Body fat content influences the body composition response to nutrition and
exercise. Ann N Y Acad Sci. 2000 May;904:359–65.
6. Hall KD. Body fat and fat-free mass inter-relationships: Forbes’s theory revisited. Br J
Nutr. 2007 Jun;97(6):1059–63.
7. El Ghoch M, Pourhassan M, Milanese C, Müller MJ, Calugi S, Bazzani PV, et al.
Changes in lean and skeletal muscle body mass in adult females with anorexia nervosa
before and after weight restoration. Clin Nutr. 2017;36(1):170–8.
8. Trexler ET, Smith-Ryan AE, Blue MNM, Schumacher RM, Mayhew JL, Mann JB, et al.
Fat-Free Mass Index in NCAA Division I and II Collegiate American Football Players. J
Strength Cond Res. 2017;31(10):2719–27.
9. Abe T, Buckner SL, Dankel SJ, Jessee MB, Mattocks KT, Mouser JG, et al.
Skeletal muscle mass in human athletes: What is the upper limit? Am J Hum Biol.
2018;30(3):e23102.
10. Hattori K, Kondo M, Abe T, Tanaka S, Fukunaga T. Hierarchical differences in body
composition of professional Sumo wrestlers. Ann Hum Biol. 1999 Apr;26(2):179–84.
11. Stratton M, Harty P, Smith R, Dellinger J, Johnson B, Benavides M, et al. Body Fat Gain
Automatically Increases Lean Mass by Changing the Fat-Free Component of Adipose
Tissue. Int J Exerc Sci. 2020 Feb 17;2(12).
12. Stodden DF, Galitski HM. Longitudinal effects of a collegiate strength and conditioning
program in American football. J Strength Cond Res. 2010 Sep;24(9):2300–8.
13. Jacobson BH, Conchola EG, Glass RG, Thompson BJ. Longitudinal morphological and
performance profiles for American, NCAA Division I football players. J Strength Cond
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Res. 2013 Sep;27(9):2347–54.
14. Trexler ET, Smith-Ryan AE, Mann JB, Ivey PA, Hirsch KR, Mock MG. Longitudinal
Body Composition Changes in NCAA Division I College Football Players. J Strength
Cond Res. 2017 Jan;31(1):1–8.
15. Borchers JR, Clem KL, Habash DL, Nagaraja HN, Stokley LM, Best TM. Metabolic
syndrome and insulin resistance in Division 1 collegiate football players. Med Sci Sports
Exerc. 2009 Dec;41(12):2105–10.
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Metab. 2017 Oct;27(5):458–66.
17. Dulloo AG, Miles-Chan JL, Schutz Y. Collateral fattening in body composition
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18. Beals JW, Burd NA, Moore DR, van Vliet S. Obesity Alters the Muscle Protein Synthetic
Response to Nutrition and Exercise. Front Nutr. 2019;6:87.
19. Hulston CJ, Woods RM, Dewhurst‐Trigg R, Parry SA, Gagnon S, Baker L, et al.
Resistance exercise stimulates mixed muscle protein synthesis in lean and obese young
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█
58
Study Reviewed: Eccentric Exercise Per Se Does Not Affect Muscle Damage Biomarkers:
Early and Late Phase Adaptations. Margaritelis et al. (2020)
Does Eccentric Training Always
Cause More Muscle Damage?
BY GREG NUCKOLS
Eccentric training causes more muscle damage than concentric
training in untrained subjects, but how much can we adapt to it
over time? A recent study examined muscle damage responses
following 10 weeks of maximal concentric-only and eccentric-only
training. It found that, after about seven weeks, neither eccentric
nor concentric still caused substantial muscle damage.
59
KEY POINTS
1. Subjects were split into two groups and performed isokinetic knee extensions once
per week for 10 weeks. Both groups performed 5 sets of 15 maximal repetitions per
session. One group did concentric-only reps, and the other did eccentric-only reps.
2. Over the 10 weeks of training, researchers monitored multiple indirect markers of
muscle damage and inflammation for up to five days following each training session.
3. After the first couple of training sessions, the eccentric training group
experienced considerably more muscle damage than the concentric training
group. However, by approximately week seven, the muscle damage response
was similar between groups.
I
4. It appears that muscles can almost fully adapt to protect themselves from eccentric
training-induced muscle damage. While eccentric training causes more damage in
untrained subjects, eccentric stress that you’re accustomed to likely doesn’t cause
very much damage.
t’s commonly believed, for good reason, that eccentric training causes more
muscle damage than concentric training. However, the authors of the presently
reviewed study (1) asked a rather intuitive
question: Over time, can people adapt to eccentric training, such that it will eventually
cause a similar amount of muscle damage as
concentric training?
To answer this question, they had young men
perform either eccentric-only or concentric-only knee extensions once per week for 10 weeks.
Training consisted of 5 sets of 15 maximal
eccentric-only reps in one group, and 5 sets
of 15 maximal concentric-only reps in another group. The researchers assessed multiple
indirect markers of muscle damage (maximal
force output, muscle soreness, pain-free range
of motion, and creatine kinase) and inflammation (C-reactive protein) for up to five days after each training session. While the eccentric
training group experienced considerably more
muscle damage after the first few workouts,
by approximately week seven, muscle damage
was similar between groups and negligible in
both groups. Therefore, it seems that people can
adapt to pretty extreme eccentric training, until
it eventually causes negligible muscle damage.
Purpose and Hypotheses
Purpose
The purpose of the study was to examine
whether the difference in muscle damage between eccentric and concentric exercise would
be attenuated following 10 weeks of eccentric-only versus concentric-only training.
Hypotheses
No hypotheses were stated, but the wording of
the introduction suggests that the authors expected that, after 10 weeks of training, eccentric-only training would no longer cause more
muscle damage than concentric-only training.
60
through a 90-degree range of motion (from
full knee extension to 90 degrees of flexion). They were “verbally encouraged” (e.g.
grad students yelled at them) to exert maximal force on every rep. Subjects were also
encouraged to not use anti-inflammatories
during the study.
Before and after the 10 weeks of training,
subjects’ body mass and body composition
were assessed. All other measures listed below were assessed every week throughout the
training period.
Subjects and Methods
Subjects
24 men completed this study. Training status
wasn’t mentioned, so I assume the subjects
were untrained. The subjects’ anthropometric
characteristics can be seen in Table 1.
Experimental Design
Subjects were randomized into two groups and
trained for 10 weeks. One group performed
eccentric-only seated knee extensions, and
one group performed concentric-only seated
knee extensions. Both groups trained once
per week, performing 5 sets of 15 maximal
reps on an isokinetic dynamometer, at an angular velocity of 60°/s. They rested for two
minutes between sets and performed all reps
Pain-free knee range of motion (how far
the knee could be bent passively before the
quads felt discomfort), delayed onset muscle
soreness (DOMS) assessed in a squatting position, isometric peak knee extension torque
(at 90° of knee flexion), concentric peak
knee extension torque (at 60°/s), and eccentric peak knee extension torque (at 60°/s)
were assessed before each training session,
and 1, 2, 3, and 5 days after each training
session. Blood draws were also performed
before each training session two days after
each training session in order to assess plasma creatine kinase and C-reactive protein
levels. Creatine kinase is an indirect marker
of muscle damage, and C-reactive protein is
a marker of inflammation.
Findings
Following the first training session, every single marker of muscle damage or inflammation
was elevated to a greater degree in the eccentric-only group (for all five days post-training, for most measures). Pain-free range of
motion was lower, knee extension torque was
61
reduced to a greater extent, DOMS was greater, and creatine kinase and C-reactive protein
levels were higher. By week 10, every single
marker of muscle damage or inflammation
had a similar post-training response in both
groups, and neither group showed any indication of post-workout muscle damage. The
damage responses (lack of responses, really)
got more similar week-to-week until approximately week seven, and from week eight onward, markers of muscle damage following
each workout were similar between groups.
Strength results were in keeping with the
principle of specificity: the concentric-only
group increased maximal concentric torque
to a greater degree than eccentric torque (+25
% vs. +16%), while the eccentric-only group
increased maximal eccentric torque to a
greater degree than concentric torque (+20%
vs. +8.5%). Isometric peak torque increased
to a similar extent in both groups (~12%).
Interpretation
This is a study I’ve been wanting to see for
a long time. It really tests the extent of the
62
repeated bout effect. We’ve discussed the repeated bout effect in MASS before, but briefly, it’s the term used to refer to the collective
set of adaptations that make your muscles
more resistant to damage when they’re repeatedly exposed to a given stressor that initially
caused muscle damage (2). Adaptations that
contribute to the repeated bout effect are why
muscle soreness is severely attenuated after
a few weeks of resistance training. We’ve
known for a long time that muscle damage following resistance training decreases
as training experience increases. However,
we’ve also known for a long time that unaccustomed eccentric loading causes way more
muscle damage than unaccustomed concentric loading (3). The present study sought
to determine whether people could adapt to
eccentric exercise to the point that it no longer caused any more damage than concentric
training. In other words, is the repeated bout
effect powerful enough for your muscles to
reach the point that they experience virtually
no muscle damage, even after extreme eccentric loading?
63
The answer seems to be a resounding “yes.”
And to be clear, the eccentric training protocol used in the present study was absolutely
brutal. 5 sets of 15 maximal eccentric contractions is not the same thing as 5 sets of 15
normal reps. I don’t care who you are: If you
don’t habitually do a lot of high-rep maximal
eccentric training, the eccentric training protocol used in the present study would absolutely cripple you for at least 2-3 days. Following their first training session, maximal
knee extension torque in the eccentric training group declined by about one-third from
pre-training to two days post-training. They
transiently lost almost a quarter of their painfree range of motion. Suffice it to say, the
eccentric training protocol is more extreme
than any eccentric loading you expose yourself to during the course of “normal” training.
In other words, if the repeated bout effect can
eventually protect against virtually all muscle damage during the training protocol used
in the eccentric training group in the present study, severely attenuating muscle dam-
THE ECCENTRIC
TRAINING PROTOCOL
USED IN THE
PRESENT STUDY WAS
ABSOLUTELY BRUTAL.
THIS STUDY SUGGESTS
THAT ECCENTRIC TRAINING
IS INHERENTLY MORE
DAMAGING THAN
CONCENTRIC TRAINING BUT
THAT MUSCLES ARE CAPABLE
OF ADAPTING TO AND
PROTECTING THEMSELVES
AGAINST RELATIVELY
EXTREME ECCENTRIC
TRAINING OVER TIME.
age responses following “normal” resistance
training should be a walk in the park.
Now, with that being said, I’m not sure I
agree with the interpretation put forth by the
authors of the present study. They claim that
their results show that eccentric training is
not more inherently damaging than concentric training per se, evidenced by the fact that
muscle damage was essentially zilch after
10 weeks of either eccentric-only or concentric-only training. Using the same logic, I could claim that rubbing my skin with
sandpaper doesn’t inherently damage my
skin more than rubbing my skin with silk per
se, because my skin would develop protective callouses if I repeatedly rubbed it with
64
sandpaper. In other words, I think this study
suggests that eccentric training is inherently
more damaging than concentric training (due
to the huge difference in damage responses
between groups from week 1 through 5 of the
training intervention), but that muscles are
capable of adapting to and protecting themselves against relatively extreme eccentric
training over time.
This study should help quell a common fear
I hear from lifters: “I’m not getting sore after training. Does that mean I’m not training
hard enough?” If the subjects in the present
study reached the point that they were no
longer sore after 75 maximal eccentric contractions (again, a more extreme stimulus
than most people have any need to expose
themselves to), it shouldn’t be shocking if
you stop getting sore following normal resistance training. I’ve found that some people
simply get DOMS more easily than others,
but if you’re not getting DOMS, that doesn’t
necessarily mean you’re simply not training
hard enough. Soreness is a poor indicator that
you’ve exposed your muscles to a sufficient
stimulus for positive adaptations to occur.
Conversely, you may now be wondering why
you do consistently get sore after training.
After all, if the repeated bout effect can wipe
out virtually all muscle damage following
an extreme eccentric training protocol, why
are you still getting sore from moderate volumes of “normal” resistance training? I think
there are two likely culprits. The first is range
of motion. The subjects trained their quads
thought 0 to 90° of knee flexion, which is a
perfectly normal range of motion for knee extensions, but still ≥30° away from full knee
IF YOU’RE NOT
GETTING DOMS,
THAT DOESN’T
NECESSARILY MEAN
YOU’RE SIMPLY
NOT TRAINING
HARD ENOUGH.
flexion ROM. It could be that the repeated
bout effect isn’t capable of ameliorating all
muscle damage when the muscles are trained
at long muscle lengths. We know that as
muscle length increases, force created by and
transmitted through passive structures in the
muscle increases. It could be that high forces, combined with a non-negligible amount
of strain on those passive tissues, presents a
large enough damage response that the repeated bout effect is simply unable to wipe
out the damage response entirely. The second potential culprit is variety. When your
muscles are repeatedly exposed to a stressor,
the repeated bout effect confers protection
against damage, but the degree of protection
depends on specificity to some degree. If you
change your rep cadence, rep range, technique, or exercises targeting a specific mus-
65
cle group, you may not have full protection
against this new, slightly different stimulus.
To be clear, if you typically do front squats
for sets of 5, and you switch to back squats
for sets of 10, you’ll still experience a greater degree of protection than someone who’s
never lifted weights before, but you’ll likely
experience less protection than someone who
always does back squats for sets of 10.
One interesting finding of this study was that
concentric-only training caused very little
muscle damage, even when performed maximally with reasonably high volume. Thus,
if you wanted to use a pushing/pulling sled
for some concentric-only training, you could
probably get away with it while not interfering much (if any) with the rest of your training, since it’s unlikely to cause a meaningful
degree of muscle damage.
While we’re comparing eccentric and concentric training, it’s worth discussing strength
and hypertrophy implications. The strength
implications are straightforward, in my opinion: the principle of specificity reigns supreme. Concentric training will improve concentric strength more than eccentric strength,
while eccentric training will improve eccentric strength more than concentric strength.
For hypertrophy, it was long believed that
eccentric training caused disproportionately
more muscle growth than concentric training. A 2017 meta-analysis found that while
eccentric training did tend to cause more hypertrophy than concentric-only training, the
difference wasn’t quite statistically significant (+10% vs. +6.8%; p = 0.076; 4). Additionally, a recent study also found that concentric-only training and a combination of
eccentric and concentric training caused basically identical growth (5). All things considered, I do suspect that it’s a good idea to
include eccentric work in your hypertrophy
training (which you can accomplish with basically any normal isotonic weight room exercise), but I doubt eccentric-only training is
necessary. Furthermore, if you wanted to do
some concentric-only training for some additional (virtually) damage-free training volume, it’s likely to cause a meaningful amount
of growth (though perhaps slightly less on a
per-set basis than training that includes an eccentric component). It’s worth noting, however, that concentric-only hypertrophy training is hard to pull off without specialized
equipment (like dynamometers). The best
practical option is sled work for most people, but finding enough space and appropriate
loads for hypertrophy work can be a hassle
(the line between a load you can’t move, and
an appropriate concentric 10RM is generally
pretty small for sled work).
In the present study, it took approximately
seven weeks for markers of muscle damage
and inflammation following eccentric training to drop to levels that were comparable to
those seen following concentric training. I
suspect the number of training sessions (also
seven) is more relevant than the amount of
chronological time elapsed. Keeping in mind
that the eccentric training protocol was more
grueling than the sort of training most people typically do, I think this suggests that the
repeated bout effect should be able to attenuate muscle damage about as much as it is
capable of being attenuated within seven or
fewer instances of repeating the same stimu-
66
lus. To me, this seems relevant for evaluating
if the level of volume on a given program is
appropriate, following large program tweaks,
or as you ease back into training following
a layoff. You should complete at least seven or eight workouts per muscle group before making a determination (in other words,
at least four weeks of training if using a frequency of twice per muscle group per week,
or three weeks of training if using a frequency of three times per muscle group per week,
or 7-8 weeks of training if using a frequency
of once per muscle group per week). Early
on in a new program, an appropriate level of
volume may initially seem too high, if the
program differs substantially from the training that directly preceded it. During the first
≤7-8 workouts per muscle group, you’ll be
experiencing more muscle damage than you
will throughout the rest of the program, so
you may be encouraged to decrease training
volume after the first week or two of training.
However, if you just stick it out for another week or two while your muscles become
less susceptible to damage on your new training program, you may find that the overall
level of volume is perfectly appropriate for
the rest of the training cycle. Conversely, if
you’re still having major issues recovering
after about four weeks of training, the overall
volume (or cumulative stress imposed by the
program) is likely too high.
Finally, this study makes me wonder if these
results would extend to failure training. In
studies that compare muscle damage and
recovery responses following failure and
non-failure training, failure training generally leads to greater damage and longer recov-
ery times. However, it’s possible that people
adapt to failure training over time, eventually
reaching the point where occasional sets to
failure don’t cause more muscle damage than
non-failure training. If the subjects in this
study could adapt to 75 maximal eccentric
reps per workout, then I don’t see why people
couldn’t also adapt to performing a few sets
to failure per muscle group per workout or
per week (primarily on single-joint exercises,
for safety reasons). Based on other research
in trained subjects, it appears that training to
failure tends to cause less soreness when it’s
spread throughout the week, rather than concentrating a lot of failure sets into a single
session for each muscle group (6). Speaking
from experience, if I take a set to failure after avoiding failure for a long time, I know
I’ll really be feeling that failure set for the
next 48-72 hours. However, if I’m training
to failure more frequently, I find that doing
some occasional sets to failure doesn’t seem
to have a meaningful negative impact on my
recovery. That’s just my anecdote, though,
so generalize at your own risk. It’s an area
where I’d like to see more research.
Next Steps
As mentioned, I’d love a study examining
whether this principle extends to failure versus non-failure training. A study could have
one group performing something like 4 sets
of approximately 10 reps to failure, another
performing 5 sets of approximately 8 reps
with 2 reps in reserve, and a third performing
6-7 sets of approximately 6 reps with 4 reps
in reserve (e.g. matching for intensity and
volume load, while manipulating proximity
67
APPLICATION AND TAKEAWAYS
While eccentric training that you’re unaccustomed to can cause considerable muscle
damage, most people can adapt to that stressor within a few weeks and protect their
muscles from most of the damage via the repeated bout effect.
to failure). The researchers could copy the
muscle damage assessments from the present
study to see if (or how quickly) muscle damage responses normalize between groups.
68
References
1. Margaritelis NV, Theodorou AA, Chatzinikolaou PN, Kyparos A, Nikolaidis MG,
Paschalis V. Eccentric exercise per se does not affect muscle damage biomarkers: early
and late phase adaptations. Eur J Appl Physiol. 2020 Nov 6. doi: 10.1007/s00421-02004528-w. Epub ahead of print. PMID: 33156414.
2. Hyldahl RD, Chen TC, Nosaka K. Mechanisms and Mediators of the Skeletal Muscle
Repeated Bout Effect. Exerc Sport Sci Rev. 2017 Jan;45(1):24-33. doi: 10.1249/
JES.0000000000000095. PMID: 27782911.
3. Proske U, Morgan DL. Muscle damage from eccentric exercise: mechanism, mechanical
signs, adaptation and clinical applications. J Physiol. 2001 Dec 1;537(Pt 2):333-45. doi:
10.1111/j.1469-7793.2001.00333.x. PMID: 11731568; PMCID: PMC2278966.
4. Schoenfeld BJ, Ogborn DI, Vigotsky AD, Franchi MV, Krieger JW. Hypertrophic Effects
of Concentric vs. Eccentric Muscle Actions: A Systematic Review and Meta-analysis. J
Strength Cond Res. 2017 Sep;31(9):2599-2608. doi: 10.1519/JSC.0000000000001983.
PMID: 28486337.
5. Mallinson JE, Taylor T, Constantin-Teodosiu D, Billeter-Clark R, Constantin D, Franchi
MV, Narici MV, Auer D, Greenhaff PL. Longitudinal hypertrophic and transcriptional
responses to high-load eccentric-concentric vs concentric training in males. Scand J Med
Sci Sports. 2020 Nov;30(11):2101-2115. doi: 10.1111/sms.13791. Epub 2020 Aug 26.
PMID: 32762021.
6. Gomes GK, Franco CM, Nunes PRP, Orsatti FL. High-Frequency Resistance
Training Is Not More Effective Than Low-Frequency Resistance Training in
Increasing Muscle Mass and Strength in Well-Trained Men. J Strength Cond Res.
2019 Jul;33 Suppl 1:S130-S139. doi: 10.1519/JSC.0000000000002559. PMID:
29489727.
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69
Study Reviewed: Effect of Resistance Training to Muscle Failure Vs. Non-Failure on Strength,
Hypertrophy and Muscle Architecture in Trained Individuals. Santanielo et al. (2020)
Time to Reframe the Proximity to
Failure Conversation
BY MICHAEL C. ZOURDOS
It’s time to stop asking if training a few reps shy of failure is okay,
as I think we have enough evidence to support this notion. Rather,
it’s time to reframe the proximity to failure conversation and ask,
how far can we train from failure? It may be farther than you think.
70
KEY POINTS
1. This study had 14 trained men train the unilateral leg press and leg extension twice
per week. Subjects trained one leg to failure and were instructed to stop sets on the
other leg before they reached failure.
2. On average, subjects stopped sets in the non-failure leg with about 1.5 repetitions
in reserve. There were no significant differences between groups for quadriceps
hypertrophy or strength outcomes. However, muscle growth occurred at a 4.6%
faster rate and leg press 1RM increased at a 4.4% faster rate in the non-failure leg.
3. This study adds to an increasing body of literature that suggests that training a few
reps shy of failure is just as good if not better than failure training for hypertrophy
and strength outcomes. We should now turn our attention to determining how far
from failure someone can train while maximizing these outcomes.
T
he debate over the necessity of
training to failure has intensified
in recent years. In MASS, we’ve
covered training to failure many times (see
“training to failure” here) and have even
internally debated how far you can train
from failure and still maximize adaptations
(read here; listen here). The reviewed study
from Santanielo (1) was a within-subjects
design, and had 14 trained men perform leg
extensions and leg press twice per week
for 10 weeks. Subjects trained one leg to
failure at 75% of one-repetition maximum
(1RM) on both exercises, and the other leg
shy of failure. Researchers instructed the
lifters to stop sets on the non-failure leg
according to their perception of fatigue before reaching failure. Before and after the
10 weeks, researchers tested vastus lateralis
(lateral quad) cross-sectional area, leg press
and leg extension strength, and muscle architecture (fascicle length and pennation
angle). Subjects performed more volume
and reps per set on the failure leg, and sub-
jects trained the non-failure leg to ~1.5 repetitions in reserve (RIR) on average. Both
training styles increased strength and size
and improved muscle architecture, with no
statistically significant differences between
groups. However, the cross-sectional area
and leg press 1RM findings leaned in favor
of the non-failure leg. Specifically, quad
cross-sectional-area increased by 13.5% in
the failure leg and 18.1% in the non-failure
leg (effect size of 0.27 in favor of non-failure). Leg press 1RM increased 4.4% more in
the non-failure leg; however, the effect size
was only trivial (0.18) after a small sample size correction. These findings suggest
that training 1-2 reps shy of failure on lower
body exercises, on average, produces at least
similar, and possibly larger hypertrophy
and strength gains than training to failure.
At this point, I think we can confidently say
that training 1-2 reps shy of failure is just as
good as (if not better than) always training
to failure for hypertrophy and strength. In
my opinion, we should now move on from
71
discussing failure versus non-failure and try
to answer the question, “how far from failure can someone train and still maximize
hypertrophy and strength?” Therefore, this
article will discuss the following:
1. Review the overarching failure versus
non-failure literature for both hypertrophy
and strength.
2. Discuss how far from failure training can
occur and still maximize hypertrophy.
3. Examine the practical limitations of failure training.
4. Discuss how training to failure, or even a
particular RPE/RIR target, is not an allor-none principle.
5. Examine the failure data concerning multiand single-joint exercises independently.
Purpose and Hypotheses
Purpose
The purpose of this study was to compare the
changes in quadriceps hypertrophy, leg press
and leg extension strength, muscle architecture, and muscle activation in trained men
who trained one leg to failure over 10 weeks
and the other leg 1-2 reps shy of failure.
Hypotheses The researchers hypothesized that there
would be no differences between training
paradigms for any outcome measure.
Subjects and Methods
Subjects
14 men who had been performing the leg press
and leg extension exercises at least twice per
week for the previous two years participated
in the study. Table 1 displays additional subject details.
Study Overview
This study used a within-subjects design
to test the influence of training to failure
versus training shy of failure on muscle
cross-sectional area, strength, muscle architecture, and electromyography (EMG)
outcomes over 10 weeks. A within-subjects
design means that 14 subjects performed the
unilateral leg press and leg extension for 10
weeks, and one leg trained these exercises
to failure while the other leg trained shy of
failure. All outcome measures were tested
before and after the 10 weeks. Ultrasound
assessed muscle cross-sectional area of the
vastus lateralis (lateral quadriceps muscle),
72
and strength was measured via a leg press
and leg extension 1RM.
tested 1RM during week five, and from that
point on, subjects used 75% of the new 1RM.
Outcome Measure Explanation
Rather than prescribing the same number of
sets for all subjects, the researchers asked
the lifters to report how many sets they did
for quadriceps each week prior to the study.
Then, researchers prescribed a 20% increase
in the number of sets for each individual and
split the total number of sets in half between
the two exercises. For example, if someone
performed 10 sets of quads training per week
before the study, they would have been prescribed 12 sets total with 6 sets on each exercise. Subjects performed 11.5 ± 5.1 per week
on the leg press and 11.6 ± 5.2 sets per week
on the leg extension. The range of sets performed was 4-25 on both exercises.
Ultrasonography assessed muscle pennation
angle and fascicle length. In brief, muscle
pennation angle is the angle at which fibers
attach to the tendon. In general, an increased
pennation angle is a positive adaptation to resistance training, and is associated with greater single-fiber cross-sectional area and force
production (2). Resistance training has also
been shown to increase fascicle length (3) due
to adding sarcomeres in a series. Therefore,
increases in both of these measures are positive adaptations. Researchers assessed EMG
amplitude during the last three repetitions of
each set during the 10-week training period,
and compared the EMG amplitude between
failure and non-failure training.
Training Program
Subjects trained only the leg press and leg extension twice per week for 10 weeks. All subjects had one leg assigned to failure training
and one leg assigned to non-failure training.
Seven individuals had their dominant leg assigned to failure training, and seven people
had their dominant leg assigned to non-failure training. Failure was defined as not being
able to perform another rep through the full
range of motion. For non-failure training, the
researchers instructed subjects to stop the set
shy of failure according to their perception of
fatigue, and not worry about the number of
reps performed. In other words, subjects were
asked to train shy of failure but were not told
how close to train to failure. Load wasn’t adjusted from week to week, but the researchers
Statistical Issues
This study used a mixed model analysis of
variance (ANOVA) for analysis, which is typical for hypothesis testing in the applied physiology literature. When using this type of test
or standard hypothesis testing (i.e., ANOVA
or t-test), a hypothesis is usually stated, such
as “we hypothesize that failure training will
lead to greater strength and muscle growth
than non-failure training.” Then, based on
the analysis results, the null hypothesis (i.e.,
the default that there is no difference between
groups) will be rejected (i.e., the hypothesis
was supported), or you will fail to reject the
null hypothesis. Failure to reject the null hypothesis doesn’t mean that the outcomes are
similar or that the null hypothesis is correct;
it just means that you cannot conclude there
is a significant difference. This last point is
perhaps the most important in our current
context. In the reviewed study, the authors
73
hypothesized failure and non-failure training
would produce similar adaptations. Therefore, since they hypothesized that adaptations would be similar, they need to test if the
outcomes are indeed similar between groups.
Remember, just above, we noted that with
typical hypothesis testing, you could only
conclude that outcomes are significantly different between groups or not, but you can’t
conclude that outcomes are similar. Thus,
when the hypothesis is that outcomes will be
similar, equivalence testing should be used.
When equivalence testing (4) is used, an
equivalence interval is set before the analysis. The equivalence interval sets an upper boundary and a lower boundary for the
range of differences that we consider small
enough to consider practically equivalent.
When you compare two groups, you’ll calculate the difference between them, along
with a confidence interval for that difference value. Equivalence testing will tell
you whether or not the confidence interval
for the between-group difference is entirely
contained within the upper and lower equivalence boundaries. If the confidence interval
of the difference between groups is entirely
contained inside of the equivalence interval,
then the difference between groups is statistically similar or equivalent. If any part of
the confidence interval of the between-group
difference extends outside of the equivalence
boundaries, then we have to acknowledge the
possibility that a practically meaningful difference exists, and we can no longer confidently assert that the groups are statistically
equivalent. So, with equivalence testing, you
cannot conclude that a significant difference
is observed; you can only conclude that the
two groups’ values are not equivalent, so the
possibility of a practically meaningful difference cannot be ruled out. In short, since the
researchers hypothesized similar outcomes
between groups, equivalence testing should
have been used.
Despite the above, I will present the findings as the authors did because I think it provides an accurate picture. I’ve also added between-group effect sizes with a small sample
size correction for some measures.
Findings
Reps Performed, Volume, Proximity to Failure
Subjects performed 13.6% more reps per set
(failure: 12.0 ± 2.1, non-failure: 10.4 ± 2.8)
and 11.5% more volume when training to
failure versus non-failure training. Over the
entire study, subjects performed non-failure
training to an average of 1.6 ± 1.8 RIR. Importantly, the researchers did not explicitly
state how the RIR was determined on the
non-failure leg. It’s possible the RIR in the
non-failure group (seen in the findings section) is self-reported; however, the difference
in reps performed between training styles was
1.6 and the RIR in the non-failure group was
also 1.6. Therefore, it’s possible the RIR just
represents the difference in reps performed
between training styles.
Longitudinal Outcomes
All outcome measures (cross-sectional area,
1RM strength, muscle architecture, and
EMG) significantly increased from pre- to
post-study with no statistically significant
74
differences between groups. Table 2 shows
that all changes seemed to be pretty similar
between groups, except for 4.6% and 4.4%
greater increases in muscle cross-sectional
area and leg press 1RM, respectively, both
in favor of non-failure training. The between-group effect sizes were 0.27 (small)
for cross-sectional area and 0.18 (trivial) for
leg press 1RM. Pennation angle also had a
between-group effect size of 0.46 in favor of
75
non-failure training. Figure 1 shows the individual changes for cross-sectional area and
leg press strength from pre- to post-study.
Interpretation
I’ll be more cautious later on, but I’ll state my
honest opinion for now: training shy of failure is just as good and probably better than
training to failure for both hypertrophy and
strength, and the presently reviewed study
enhances that view. You could interpret the
reviewed research (1) as having no group differences or a slight win for non-failure training. While there is some conflicting evidence
in untrained individuals (5) most of the recent literature which has had individuals train
more than once per week (more on frequency
later) have shown similar (6, 7, 8, 9) or greater (10, 11) hypertrophic adaptations in favor
of non-failure versus failure training. You
TRAINING SHY OF
FAILURE IS JUST AS
GOOD AND PROBABLY
BETTER THAN TRAINING
TO FAILURE FOR
BOTH HYPERTROPHY
AND STRENGTH.
could add the current study to either column.
Despite being a non-failure advocate, I’m
sensitive to the other side because I get the
impulse behind it. The impulse to think that
training until you can’t do any more reps is superior is not an irrational thought. The effective reps paradigm suggests that you achieve
maximal motor unit recruitment during the
last five reps of a set to failure, and there is
more mechanical tension for each rep closer to failure; thus, each rep closer to failure
causes more growth. I’m not sure I buy into
the effective reps paradigm’s mechanistic arguments, and based on the evidence, I surely
don’t buy into the training recommendations.
I won’t rehash the mechanistic underpinnings
that Greg has written so eloquently about before in his Stronger By Science article; rather, I’ll stick to the practical outcomes, which
are what should matter most.
In my opinion, we should reframe the failure debate from “do you have to train to failure” to “how far can you train from failure
and still maximize hypertrophy?” Training
farther from failure may also have additional
practical benefits related to fatigue, muscle
damage, single-session volume, weekly volume, and weekly frequency, but we’ll return
to those later. For now, let’s look at the evidence. Most of the studies comparing failure
versus non-failure training are similar to the
currently reviewed research, in that they compare failure to training just a rep or two shy
of failure. About a year ago, Greg reviewed
a study from Lasevicius et al (9 – MASS Review) which had untrained lifters, in a within-subjects design, train knee extensions to
failure or not to failure. While proximity to
76
failure was not controlled in that study, subjects likely had at least seven reps in the tank
when performing non-failure training. Still,
they experienced similar hypertrophy and
strength compared to failure training (however, note that the subjects in the non-failure
group performed more sets in order to equate
total reps between groups). Further, Carroll
et al (10 - MASS Review) had a group of
subjects train to ~4-5 RPE over 10 weeks on
a variety of lifts (squat and bench press included), and these lifters experienced greater
quadriceps growth than a group who trained
to failure. The idea that you can perform a
decent amount of training at a 5RPE (5RIR)
and still maximize hypertrophy is something
that I thought seriously about in 2016 after
we wrapped both an acute RPE/RIR accuracy study (12) and Dr. Helms’ Ph.D. thesis
(13). For the acute study, subjects performed
one set to failure on the squat at 70% of 1RM
and predicted when they had 5, 3, and 1 RIR
during the set. Subjects under-predicted RIR
by about 5, 3.5, and 2 reps at each threshold. In other words, subjects had on average
a 10 RIR when they predicted a 5 RIR. Then,
Dr. Helms’ study compared two groups who
trained the squat and bench three times per
week over eight weeks of training, and found
that a group who trained, on average, to a
self-reported 4-5 RIR experienced similar
muscle growth to a group who trained to a
2-3 RIR. Taken together, these studies suggest that the well-trained lifters in Helms’
study trained considerably farther from failure than reported. Other studies (14 – MASS
Review, 15 – MASS Review) have reported that subjects can predict intra-set RIR to
within one rep after the first set of an exer-
cise. So, I don’t think the subjects in Helms’
study were 3-5 reps off on every set, but the
main points are 1) 4-5 RIR training produced
similar muscle growth as 2-3 RIR training
and 2) the average number of RIR was probably even lower than reported. To me, these
findings suggest that trained lifters with a
high training frequency can take most sets
on compound lifts to around a 5 RIR and
still maximize hypertrophy on major muscle
groups (i.e., quads and pecs). One valid criticism of this interpretation is that if RIR was
under-predicted and there was no group training to a 1 RIR, then it’s fallacious to conclude
that 5 RIR training is sufficient. I’m sympathetic to that argument, but that lateral quad
hypertrophy in this study was 6.6%, similar
to a study (+ 4.88%) (16), but with subjects
training much closer to failure.
I don’t see much data on the other side of the
argument. You could argue that studies using
cluster sets or intra-set rest could demonstrate
that training close to or at failure is necessary, but I don’t think it’s an apples-to-apples
comparison. A commonly cited study from
Goto et al 2005 (17) had subjects perform leg
extensions for either 5 sets of 10 reps to failure for 12 weeks or 5 sets of 10 reps with a
10RM load but with a 30-second intra-set rest
after the fifth rep to ensure subjects stayed
shy of failure. This led to potentially a 1-3
RIR at the end of all 10 reps. Quadriceps hypertrophy was more than double in the failure
(+ 12.9%) versus the intra-set rest (+ 4.0%)
group. However, this is more of an extended cluster set and not indicative of how most
people train. Therefore, I weigh the Carrol,
Lasevicius, and Helms studies more highly
77
than the Goto study. Nonetheless, I think it’s
also fair to say that there is not enough data
to definitively conclude how far someone
can train from failure and maximize hypertrophy. I would say that someone can train
to around a 5 RIR for the most part when using moderate to heavy load training (i.e., not
light loads), but it may be even farther from
failure than that (gasp). The sufficient RIR
might be 2-3 RIR, but I don’t believe the existing data suggests that. In short, we need to
reframe the question, and both opinions (i.e.,
5 RIR or 2-3 RIR) have merit, but suggesting
a 5 RIR or less is sufficient is not an outlandish statement based upon the data. I’ve heard
people say, “Well, I tried training to a 5 RIR,
and it just didn’t feel stimulating, or it didn’t
feel fatiguing.” That’s fine, but that doesn’t
negate the existing data. As with anything,
we sometimes think in a binary fashion, but
not all training must be at the same RIR. If
someone can do 13 reps at 72.5% of 1RM on
the squat and does 5 sets of 8 this would be
a 5 RIR on the first set, but the RIR would
probably be 2-3 on the final set or two.
I also see non-failure training on the main lifts
as having utility for more appropriate per-session and weekly volume and frequency. First,
training to failure on every single set or even
close to failure can be pretty fatiguing, and
it may decrease the quality of some sets performed later in a training session. If you want
to perform 4 or 5 sets of a single exercise,
then training to failure on the first few sets
might compromise the last few sets. If you
aim for a higher frequency (three times per
week or more), staying in the 3-5 RIR range
on the main lifts might be even better to mit-
igate fatigue over the next few days (18).
Further, a training frequency of 2-3 times per
week is superior to a frequency of one time
per week for strength (19) and may be preferable for hypertrophy (20, 21). One study I
haven’t mentioned so far is Karsten et al (22),
which found that quadriceps growth occurred
at a ~5% faster rate when subjects performed
4 sets of a 10RM compared to 8 sets of 5 at
a 10RM load. This means that subjects in the
non-failure group trained to about 5 RIR on
the first set and about 3 RIR on the last set.
However, Karsten only had subjects train a
muscle group once per week, and other muscles (biceps and shoulders) did not show
group differences; therefore, it’s hard for me
to weigh the Karsten study highly.
The previous paragraph focused mostly on
the main (i.e., squat and bench) movements.
Let’s now review the data on single-joint
movements. For single-joint exercises, some
data suggests that training to failure produces
greater biceps hypertrophy than training to a 3
RIR (5). At the same time, other studies have
shown no difference (6, 8) or tended to show
favorable hypertrophy in favor of non-failure
training (11). Therefore, I’d again argue for
non-failure training; however, I’d also say that
if you enjoy failure training, then single-joint
movements are the place to do it (for some exercises). As with anything, using failure training or a specific proximity to failure is not an
all-or-none thing. If I say that I believe you
can train 4-5 reps from failure for the most part
and maximize hypertrophy, that’s not the same
as saying, “you have to train 4-5 reps from
failure all the time.” In other words, if you
train muscle groups three times per week, then
78
early in the week or when you’re doing your
highest volume work, I would keep the major
lifts and other damaging exercises (i.e., flys,
RDLs, skull crushers) a bit farther from failure. Other assistance movements (i.e., curls,
lateral raises, leg extensions) could be taken to
a 1-2 RIR, with the last few sets taken to failure without issue. Then, if you train a muscle
group on Monday, Wednesday, and Friday,
you could take the last set of a main exercise
to failure and all of your assistance work to a
0-2 RIR later in the week. What’s important
is not that you identify precisely how far you
can train from failure and always do that. Instead, it would help if you kept things appropriately shy of failure when it may negatively
impact your session volume, weekly volume,
weekly frequency, or your overall fatigue and
desire to train. Conversely, if training to a 4-5
RIR is appropriate, but it decreases your desire
to train because you don’t “feel it” or enjoy
it, then you shouldn’t train that way. When I
79
coach, I learn the client’s mental makeup and
realize what type of training they enjoy. If they
enjoy training a bit closer to failure, I make
sure that they get to train closer to failure; I’m
just strategic where I pick my spots. You have
to give lifters some of what they need, but a
lot of what they want for them to buy into the
program, and the buy-in may be the most critical element for success. Table 3 shows a sample training week for legs, back, and biceps in
which all aspects of the failure spectrum are
used as described in this paragraph. I left out
chest, shoulders, and triceps to keep the table
a reasonable size, but those muscle groups
could be trained on Tuesday, Thursday, and
Saturday with the same concept.
Although we’ve alluded to strength gains
above, most of this interpretation thus far has
focused on hypertrophy. Four years ago, Davies et al (23 - read the erratum) published a
meta-analysis which concluded that there was
no difference in strength between training to
failure and training shy of failure. However,
the evidence since then has leaned in favor
of non-failure training. Carrol and colleagues
also published a paper on strength outcomes
(24 - MASS Review) from the same dataset
as the hypertrophy study cited above (10).
While the differences were not statistically
significant between groups, changes in the
non-failure group tended to be larger and were
more consistent (i.e., predictable) than the
failure group. Further, this study from Carrol
reported that training strain (based upon session RPE scores) was significantly lower than
the non-failure group. Pareja-Blanco and colleagues (7 - MASS Review) found that subjects who stopped squat sets after a 20% veloc-
ity loss over eight weeks increased squat 1RM
by 4.6% more than those who trained to a 40%
loss, which corresponded to reaching failure
on a little over 50% of the sets. Additionally,
Sanchez-Moreno (25 - MASS Review) reported about ~5% greater strength gains for pullups over eight weeks with a 25% velocity loss
versus a 50% velocity loss, which was training
close to failure. Lastly, the presently reviewed
study’s findings leaned in favor of greater leg
press 1RM increases with non-failure training.
While I don’t think training to failure with hypertrophy training is a good idea for practical
reasons, you could brush that aside and take
the view that there is no difference between
failure and non-failure, if you simply want
to train to failure. Fair enough. However, for
strength, I’m not sure you can make that case
anymore. I think the data is now suggesting
that training to failure might be inferior for
strength development. How far can you train
from failure? Like hypertrophy training, I’m
not sure if you can train at a 2-3 RIR or a 4-5
RIR for most of your sets; however, I think
it’s somewhat immaterial. You can most likely train at a 4-5 RIR with moderate loads, but
since intensity is a driver of strength, lifters
will have to work up to high loads (i.e., ≥90%
of 1RM) if looking to maximize 1RM. Once
you perform one rep at 90% of 1RM, you are
likely already at a 2 RIR. Additionally, in the
latter stages of preparing for a powerlifting
competition or test day, you may work up to
a heavy single at 0-1 RIR (i.e., 9 or 9.5 RPE).
For strength, since both volume and intensity are contributory, it’s wise to avoid failure
when performing volume training; however,
you will inevitably get close to failure when
performing intensity-type training.
80
To sum up, subjects in the presently reviewed
study training to about 1.5 RIR over eight
weeks experienced just as good, if not slightly
better, strength and hypertrophy adaptations
than when training to failure. One interesting
note about the reviewed study is that when
subjects were asked to train shy of failure, they
went pretty close to failure (1-2 RIR). This
study adds to an increasing body of literature,
which, in my opinion, clearly suggests that
non-failure training is at least as good as failure training for both strength and hypertrophy.
I would suggest that performing the majority
of your training shy of failure is preferable
for practical reasons. We should reframe the
debate regarding hypertrophy and now focus
on how far we can train from failure and still
maximize hypertrophy. I think there is a point
where you are too far from failure to maximize adaptations, which is only logical, and as
I said at the outset, I understand the impulse
to believe in failure training or the effective
reps model. However, based on the literature,
I believe the necessary proximity to the failure
threshold is lower than many think.
Next Steps
To keep it simple, I’d like to see a longitudinal study with four groups that train to 1)
failure, 2) 1-3 RIR, 3) 4-6 RIR, and 4) 7-10
RIR. I realize that some may read “7-10 RIR”
and think that it’s ridiculous. It may be ridiculous, but remember, there is data showing
that 5+ RIR is just as good if not better than
failure training, so if we really want to find
the minimum proximity to failure threshold,
then we need to investigate higher RIR training. Suppose this study is carried out on the
major exercises. In that case, I’d also like
to see muscle damage markers for up to 48
hours after some of the training sessions (i.e.,
through Wednesday after a Monday session)
and session RPE values to assess the fatigue
of each protocol. Lastly, and I’m dreaming
here, it would be great to see a 12-week follow-up with the subjects after the study to
see if they maintained training volume and
frequency, and to gauge their motivation. I’d
wager that the failure group subjects would
be a bit more discouraged at continuing the
same training volume afterward.
I BELIEVE THE
NECESSARY PROXIMITY
TO THE FAILURE
THRESHOLD IS LOWER
THAN MANY THINK.
81
APPLICATION AND TAKEAWAYS
1. The reviewed study showed that performing leg presses and leg extensions to a
1-2 RIR, on average, produced similar leg extension strength gains and similar
if not slightly greater quad hypertrophy and leg press strength gains than failure
training over eight weeks.
2. When assessing the total body of literature, it seems quite clear that training a few
reps shy of failure is just as good as failure training for hypertrophy, and is likely
better for strength gains.
3. Training to failure or a specific proximity to failure should not be an all-or-none
thing. Instead, a lifter should be strategic about where they use failure training,
which is more suited to most single-joint movements or compound movements
with lower reps performed toward the end of a training week.
82
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Study Reviewed: A Mycoprotein Based High-Protein Vegan Diet Supports Equivalent Daily
Myofibrillar Protein Synthesis Rates Compared with an Isonitrogenous Omnivorous Diet in
Older Adults: A Randomized Controlled Trial. Monteyne et al. (2020)
Do Vegan Diets Hinder
Hypertrophy?
BY ERIC TREXLER
There are many defensible reasons to shift toward a more plantbased diet, but plant-based proteins have lower quality scores
and have been shown to induce smaller acute increases in muscle
protein synthesis than animal proteins. So, will a vegan diet hinder
your gains? Read on to find out.
86
KEY POINTS
1. The presently reviewed study (1) sought to determine if high-protein (1.8g/
kg/day) omnivorous diets and vegan diets would have differing effects on the
muscle protein synthetic response to three consecutive days of unilateral leg
extension exercise in older adults.
2. For protein synthesis rates, there was not a statistically significant interaction
between group and exercise condition (p = 0.99). Both groups had similar rates
of protein synthesis in their untrained legs and experienced a similar (12-13%)
increase in protein synthesis rates when comparing their trained leg to their
untrained (control) leg.
3. As long as you’re consuming enough total protein, essential amino acids, and
leucine per meal and throughout the day, a vegan diet probably won’t hinder
your strength or hypertrophy progress. You might have to put a little more effort
into the selection of protein sources, especially during particularly high or low
calorie intakes, but it’s doable.
W
hether you’re training for strength
or physique purposes, increasing
the protein content of your muscles (that is, achieving muscle hypertrophy)
is a very favorable adaptation to resistance
training. While training drives the adaptation,
nutrition plays a permissive role in ensuring
that muscle protein balance is optimized. Intuitively, dietary protein intake is a particularly important nutrition variable for optimizing muscle protein balance, so a great deal of
research has been devoted to identifying the
ideal doses, sources, and timing strategies for
dietary protein. While there are plenty of defensible reasons to opt for a more plant-based
diet, we’ve known for a while that plant-based
protein sources tend to have lower relative
amounts of leucine and essential amino acids
(2), in addition to lower protein digestibility-corrected amino acid scores (3). Along
those lines, the acute muscle protein synthesis
response tends to be lower when plant-based
proteins are compared to equivalent doses of
animal-based proteins (2), which fuels concerns that plant-based diets may be suboptimal
for promoting hypertrophy in lifters. The presently reviewed study (1) sought to determine
if an omnivorous diet and a vegan diet, both
providing 1.8g/kg/day of total protein intake,
would have differing effects on the muscle
protein synthetic response to three consecutive days of unilateral leg extension exercise
in older adults. The sample consisted of males
and females with a mean (± standard error)
age of 66 ± 1 years, and the diets were provided to all participants, with 71% of the omnivorous diet’s protein coming from animal
sources and 57% of the vegan diet’s protein
coming from mycoprotein, which is derived
from fungi. I should note that while fungi are
not plants, I’m going to lump mycoprotein
into the “plant-based proteins” category in this
article, because we’re generally talking about
non-animal-derived, vegan-friendly proteins
87
in that type of discussion. Both groups had
pretty similar rates of muscle protein synthesis
in their non-exercised legs, and both experienced a similar (12-13%) increase in protein
synthesis rates when comparing their trained
leg to their untrained (control) leg. None of
the statistical tests suggested that the vegan
diet was significantly better or worse than the
omnivorous diet in this study. Read on to see
how these results fit with the broader literature
comparing plant-based protein sources to animal-based proteins.
Purpose and Hypotheses
Purpose
The purpose of this study was to compare
the effects of protein-matched (1.8g/kg/day)
vegan and omnivorous diets on muscle protein synthesis in the rested and exercised legs
of older adults.
Hypotheses
The researchers hypothesized that “in older
adults consuming a high-protein diet, exercise would increase daily muscle protein synthesis rates compared with rested muscle, and
by a similar extent irrespective of whether
dietary protein was primarily obtained from
animal or non-animal sources.”
Subjects and Methods
Subjects
19 healthy older adults completed the presently reviewed study. Participants were required to be between 55-75 years of age, and
were ineligible to participate if they had any
relevant health conditions, had a BMI below
18 or above 30, had recently consumed dietary supplements, or had participated in a
structured resistance training program within
the six months prior to enrollment. The methods suggest that participants were randomly
assigned to the omnivore group or the vegan
group, but they also noted that three participants were assigned to the vegan group because they were already following vegetarian diets at the time of enrollment. So, let’s
say they were “semi-randomly” assigned to
groups, which resulted in 10 subjects in the
vegetarian group (6 male, 4 female) and 9
subjects in the omnivore group (6 male, 3 female). Participant characteristics are summarized in Table 1.
Methods
Throughout this three-day intervention, participants followed an assigned diet (which
was provided by the research team) while
completing daily unilateral leg extension
88
exercise. This was an “open-label” study,
as there were some practical and logistical
challenges that precluded the blinding of
treatments. The energy content of each participant’s diet was individualized based on
their body composition and reported physical
activity level, and both groups received diets providing 1.8g/kg/day of protein. Animal
sources provided 71% of the protein in the
omnivorous diet and mycoprotein provided
57% of the vegan diet’s protein. If you’re
not familiar with mycoprotein, it’s a vegan
protein source derived from fungus, and it’s
often sold under the brand name “Quorn” (4).
The first protein meal of each day included
about 19-21g of protein provided immediately after resistance training, and the other
three meals were spaced throughout the day
and provided about 33-40g of protein, with
both groups receiving around 125-127 total
grams of protein per day. Details of the habitual diets and intervention diets for both
groups are provided in Table 2.
Each day, participants completed a unilateral
resistance training session. With the dominant leg, participants completed 5 sets of 30
repetitions of maximal concentric isokinetic
leg extensions. Each repetition involved an
80° range of motion completed at a rotational speed of 60° per second, and participants
rested for 90 seconds between sets. The researchers took muscle biopsies from the vastus lateralis muscle before and after the intervention, and implemented a deuterated water
89
dosing protocol throughout the intervention,
which allowed the researchers to quantify the
daily myofibrillar protein fractional synthesis
rate for each group. This was a very focused
research project that was designed to answer
one very direct question: do vegan and omnivorous diets providing 1.8g/kg/day of protein have divergent effects on muscle protein
synthesis over three days of resistance training? In order to answer that, each participant’s
non-exercising leg served as a control leg, so
the researchers could compare the differences between the exercising and non-exercising
leg in the vegan diet subjects to the differences between the exercising and non-exercising
leg in the omnivorous diet subjects.
Findings
Neither group experienced a statistically significant change in body mass during the trial.
Groups did not significantly differ in terms
of work completed during the exercise bouts,
or fatigue levels during each exercise trial
or throughout the week. For protein synthesis rates, there was not a statistically significant interaction between group and exercise
condition (p = 0.99). Within the omnivore
group, daily myofibrillar protein synthesis
rates were 13 ± 8% higher in the exercising
leg compared to the control leg (1.59 ± 0.12
versus 1.77 ± 0.12 %/day). Within the vegan group, daily myofibrillar protein synthesis
rates were 12 ± 4% higher in the exercising
leg compared to the control leg (1.75 ± 0.14
versus 1.93 ± 0.12 %/day). The main effect
of group (p = 0.19) was not significant, which
indicates that the vegan group protein synthesis values (including both the exercised and
non-exercised legs) were not significantly
different than the omnivore group values. The
main effect of exercise condition (p = 0.16)
90
was not significant, which suggests that protein synthesis values from the exercised legs
(from both the omnivore and vegan groups)
were not significantly different from the values from the non-exercised legs. The protein
synthesis results are presented by group and
exercise condition in Figure 1.
Interpretation
As I indicated in the methods section, this was
a pretty straightforward study with a pretty
straightforward conclusion: when comparing two diets providing equivalent calories
and total protein, a vegan diet does not significantly alter the muscle protein synthetic
response to a few days of resistance training when compared to an omnivorous diet.
Readers might be a little concerned about the
non-significant main effect for the exercise
condition. This finding indicates that muscle protein synthesis rates in exercised legs
(among both diet groups) were not significantly higher than non-exercised legs, which
may seem to suggest that the training stimulus was insufficient for the purposes of this
study. However, I’m not concerned by that.
When we look at this type of statistical test,
its significance level will be influenced by the
size of the effect, the number of participants,
and the consistency of the effect. Within the
vegan diet group, muscle protein synthesis
rates were 12 ± 4% higher in the exercised
leg than the non-exercised leg. The researchers noted that this was statistically significant
within the group; I personally wouldn’t have
run that test in the absence of a significant interaction effect, but that’s fine. The leg-to-leg
comparison within the omnivorous diet group
was not statistically significant (again, a test I
wouldn’t have run), but the magnitude of the
leg-to-leg difference was quite similar (13%).
The lack of significance is simply related to
the consistency of the effect, as indicated by
a higher standard error, and when you’ve got
a sample this small, even a little bit of unexpected variance can lead to a non-significant
finding. So, I think the training stimulus was
sufficient for the purpose of answering the
research question, and the vegan diet did not
impair protein synthesis in this study. That
might seem counterintuitive, given that plant
proteins generally have lower digestibility
and protein quality scores than animal proteins, and single doses of animal protein have
been shown to acutely stimulate more muscle
protein synthesis than protein-matched doses
of plant-based proteins. So, let’s contextualize the current findings by looking at a few
key aspects of the plant-versus-animal protein discussion: protein quality, acute muscle
protein synthesis, and longitudinal effects on
body composition.
There are numerous ways to look at protein
quality (3). The simplest way is to dichotomize them: if a protein contains all of the
essential amino acids in sufficient amounts,
it’s known as a “complete” or “quality” protein. However, there are more nuanced scales
for assessing individual proteins. For example, the protein efficiency ratio is calculated
by feeding a protein to rats and seeing how
much weight gain it induces, using casein as
the standard comparator. Net protein utilization is calculated based on direct measurements of how much nitrogen is used for tissue formation, relative to the total amount of
91
nitrogen ingested. Biological value is similar,
but is expressed relative to the total amount
of nitrogen absorbed from food rather than
the total amount of nitrogen ingested. The
protein digestibility-corrected amino acid
score (PDCAA score) is specifically calculated by considering the amino acid needs of
humans (although it’s based on the needs of a
2-5 year old child, since they do some serious
growing) and the ability of humans to actually digest the protein. That’s pretty important, because the main shortcomings of plantbased proteins relate to lacking key amino
acids and having poorer digestibility. Starting in 1989, the PDCAA score was the recommended way to rate proteins, but in 2013
people started shifting toward the digestible
indispensable amino acid score, which is a
slightly updated approach that uses a more
refined method of determining digestibility.
Apparently the PDCAA score overestimates
the amount of amino acids absorbed when directly compared to this updated approach.
If you’re interested in the actual amino
acid composition of various plant- and animal-based proteins, I would highly recommend checking out these open-access review
papers by van Vliet et al (2) and Gorissen et
al (5). They provide several helpful figures
that compare numerous proteins based on
their total protein content (as a percentage
of raw material), total essential amino acid
content, and content of just about every individual amino acid you’d care about. The figures also have a dashed line representing the
amino acid requirements for adults, which is
super helpful. Across the board, you’ll see
that animal proteins are generally of higher
relative quality (in terms of amino acid composition) than plant-based proteins. However, there’s quite a lot of variability among the
plant-based proteins; for example, corn has
a ton of leucine, but a pretty notable lack of
lysine. Pea protein has plenty of lysine, but
lacks methionine. Brown rice has a ton of
methionine, but lacks lysine. You probably
don’t need a huge review paper to convince
you that animal proteins generally have more
favorable amino acid profiles than plant proteins, but this paper is a remarkable resource
for anyone who is interested in increasing
their plant-based protein intake. There are
plenty of people who try to boost their plant
protein intake for a variety of reasons, and
this review paper provides a nice roadmap
for finding “complementary” plant proteins
that make up for each others’ insufficiencies.
The paper by van Vliet also contains plenty of information about mycoprotein, just in
case the presently reviewed study sparked
some curiosity. Essential amino acids make
up 41% of the total protein content of mycoprotein, which is pretty much as good as it
gets for non-animal-derived proteins (whey
is 52%, and beef and eggs are around 44%).
Mycoprotein also has a pretty balanced array
of essential amino acids, but the key shortcoming seems to be leucine; while many animal proteins are 8-13% leucine, mycoprotein
is only 6.2% leucine.
Of course, amino acid composition doesn’t
tell the whole story. We also have to consider things like digestibility and absorption.
Plant-based proteins generally have lower digestibility, which contributes to their lower
PDCAA scores compared to animal proteins.
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However, not all plant proteins have lower
PDCAA scores; while peanut protein has a
PDCAA score of 0.52 and rice is up around
0.75, soy isolate’s score (1.0) is equivalent
to the scores of egg and dairy-based proteins
(3). In case you were curious, the primary vegan protein source in the current study
(mycoprotein) has a PDCAA score of 0.91
(6). Unfortunately, even PDCAA scores fail
to tell the entire story. As noted by van Vliet
and colleagues, soy beans and beef have
nearly identical PDCAA scores, but beef is
superior in terms of inducing short-term muscle protein synthesis when comparing equal
doses (2). To further emphasize this point,
let’s consider a recent study (7) which formulated three different test products using
blends of pea, pumpkin, sunflower, and coconut protein to compare to whey protein isolate. All four treatments had the exact same
leucine content (2.6g), PDCAA score (1.0),
and total essential amino acid content (12g).
Given that whey provides more of the good
stuff per gram of total protein, the plantbased products had 33-34g of total protein,
whereas whey protein isolate was able to hit
those leucine and essential amino acid targets
with only 24g of total protein. Despite all the
effort dedicated to making these treatments
as equivalent as possible, the whey protein
isolate caused substantially larger increases
in blood leucine and blood amino acid levels during the four hours following ingestion,
and those factors are what ultimately enable
ingested protein to initiate protein synthesis
in muscle.
When you consider differences in amino
acid profiles, digestibility levels, and rates of
amino acid absorption and appearance in the
blood, it’s not hard to see why many previous
studies have found that a single dose of animal
protein stimulates muscle protein synthesis to
a greater extent than a protein-matched dose
of plant protein (2). However, there is some
good news. Protein synthesis rates don’t increase linearly forever; we max out the muscle
protein synthesis response of whey at a dose
of somewhere around 20-40g, depending on
some key study and sample characteristics
(8). In addition, the protein synthesis-related
shortcomings of plant-based proteins can be
overcome (to some extent) by increasing the
dose, combined with the practices of fortifying the protein source with key amino acids
or combining it with other plant proteins with
complementary amino acid profiles (2). This
at least opens the door to the possibility that
vegan diets, or heavily plant-based diets, can
still support similar levels of hypertrophy as
long as the diet contains enough total protein and suitable intakes of leucine and essential amino acids. That’s an important door
to open, as it provides an avenue by which
we can make sense of the presently reviewed
results, in which lower-quality proteins appeared to support similar levels of muscle
protein synthesis during a 3-day high-protein
diet. One final consideration to keep in mind
is that up to this point, we’ve completely
ignored muscle protein breakdown. It rarely gets the attention it deserves because it’s
more difficult to measure than muscle protein synthesis (and is therefore discussed less
frequently in research settings), but hypertrophy is all about the balance of synthesis and
breakdown. So, let’s look at some longitudinal studies that have actually compared body
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composition changes in response to resistance training while comparing plant-based
versus more animal-based protein sources.
There aren’t a ton of studies putting people on
strict vegan diets for a long time, because it’s
pretty hard to get a lot of people to sign up for
random assignment to a diet with substantial
food choice restrictions. In contrast, there are
several studies comparing supplementation
with plant-based and animal-based protein
supplements. Hartman et al compared 17.5g
doses of soy protein to milk protein over 12
weeks of resistance training, with doses consumed immediately after and one-hour after
workouts. The soy group gained 0.4kg more
than the control group, while the milk group
gained 1.5kg more. Volek et al (9) reported
that whey protein supplementation led to more
lean mass gains (3.3kg) than carbohydrate or
soy supplementation over nine months of resistance training. Those results are a bit curious, as the carbohydrate group gained more
lean mass than the soy group (2.3kg versus
1.8kg) despite lower daily protein intake (1.1g/
kg/day versus 1.4g/kg/day). A fairly recent
study compared the effects of supplementing with 24g of whey or 24g of pea protein
during CrossFit-type exercise (10). After eight
weeks, both groups improved squat and deadlift 1RM to a similar extent, and neither group
had statistically significant body composition
changes. Mobley et al (11) also failed to identify body composition advantages from either
leucine-matched whey concentrate (26.3g),
whey hydrolysate (25.4g), soy (39.2g), or leucine (2.9g) supplementation throughout 12
weeks of resistance training, as all groups experienced similar hypertrophy.
Brown et al (12) provided pretty large (33g)
doses of whey or soy protein to weight training students in a nine-week intervention, and
found that both groups achieved statistically significant hypertrophy, with both groups
gaining similar amounts of lean mass. In contrast, the training-only group did not achieve
significant gains in lean mass. Similarly, Joy
et al (13) reported that large doses (48g) of
whey protein isolate and rice protein supported similar amounts of hypertrophy over the
course of an eight-week resistance training
program, but this research group has a complicated history when it comes to supplement
trials (14, 15). Taken together, you might
conclude that plant-based protein supplements yield similar lean mass improvements
as animal-based proteins, provided that the
dose is large enough to overcome amino acid
insufficiencies in the plant-based protein.
You might also conclude that supplement
studies with protein are pretty hit-or-miss regardless of the source, and shift your focus to
the few studies that focus on the entire diet
rather than the addition of a supplement.
There are of course plenty of cross-sectional
studies indicating that getting a larger proportion of protein from animal sources is associated with better lean mass outcomes (2),
but the individuals consuming less animal
protein generally consume less total protein
overall, which is a major confounding factor.
In a longitudinal study, Campbell et al (16)
found that older adults completing a 12-week
resistance training program gained more lean
mass on an omnivorous diet (with 50% of
protein from meat) than an ovolactovegetarian (dairy and eggs allowed) diet. However,
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these results are potentially confounded by
low total protein intake in the ovolactovegetarian group (0.78g/kg), which was meaningfully higher in the omnivorous diet group
(1.0g/kg). Indeed, a subsequent study (17)
compared a 50% beef diet to an ovolactovegetarian diet with 50% of its protein coming
from soy, and made an effort to push total
protein intake a little higher in the ovolactovegetarian group. While protein intakes still
weren’t super high, and intakes in the omnivorous group were still higher than the ovolactovegetarian group (1.17g/kg versus 1.03g/
kg), both groups achieved similar increases
in muscle cross-sectional area following 12
weeks of resistance training. Even with this
between-group discrepancy and pretty modest protein intakes, the authors concluded
that getting both groups up above 1g/kg allowed the ovolactovegetarian group to effectively overcome the discrepancy in protein
source quality that would otherwise favor the
meat-eating group.
I wish there was a huge body of longitudinal
studies comparing different types of plantbased and omnivorous diets, but we’ll have
to make due with the limited data we have.
In the acute, single-dose data, it’s clear that
the shortcomings of plant proteins can be
overcome by ensuring that all amino acid
bases are covered and increasing the dose
to overcome differences in digestibility and
amino acid utilization. If we extrapolate that
out, we might be able to make sense of the
supplementation studies that show no major
differences between plant and animal sources
when 30+ grams of protein are provided, and
the fact that the plant versus animal protein
discrepancies for lean mass outcomes seem
more notable when total protein intake is lower. Along those lines, the presently reviewed
study ensured that both groups consumed a
pretty decent amount of total daily protein
(1.8g/kg), which allowed them to provide at
least 33g of protein per meal at three out of
the four daily meals. I’m not saying that the
research in this area is fully conclusive and
irrefutable, because we’re clearly grasping at
minimal amounts of longitudinal data. Nonetheless, from my perspective, that’s the most
logical way to tie these findings together into
a cohesive conclusion that isn’t contradicted
by the available cross-sectional or longitudinal data. That’s also the same general conclusion reached by van Vliet and colleagues in
their 2015 review (2). They suggest that, as
long as each meal is constructed in a way that
effectively promotes a robust increase in protein synthesis, a plant-based diet shouldn’t
impair hypertrophy. To make up for the insufficiencies of individual plant sources of protein, they recommend fortifying plant sources with the amino acids they lack, combining
complementary protein sources together, and
eating enough protein per meal to get enough
leucine and essential amino acids while overcoming differences in protein digestibility
and amino acid absorption kinetics.
This isn’t the first time we’ve leaned on
high total protein intake to rescue us from
the necessity to stress over the details of our
protein intake strategies. In my MASS article about protein distribution, I mentioned
that nuanced protein distribution strategies
probably become less relevant when sufficient total protein is being consumed daily.
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The same thing came up in my article about
time-restricted feeding, as some studies have
shown less favorable impacts on hypertrophy
when total protein intake is a little low (1.0g/
kg), but not when it’s higher (1.6g/kg). The
same conclusion was reached in a popular
2013 meta-analysis about peri-workout protein timing, in which the authors concluded
that total daily protein intake was far more
influential than specific timing in proximity to exercise bouts (18). Based on what we
currently know about single-meal responses
to protein intake, it seems that the presently
reviewed study lends support to the idea that
high overall protein intake can compensate
for lower relative quality of plant-based proteins. While the results of the current study
do not suggest it’s entirely necessary, it still
might not be a bad idea to eat a little more
total protein, along with more protein per
meal, on a plant-based diet than you otherwise would with animal-based proteins. Notably, the current study only involved unilateral leg extension as the stimulus for muscle
protein synthesis. In a study by Macnaughton
and colleagues, they noted that more strenuous full-body training programs might increase the amount of protein needed to maximize muscle protein synthesis. While their
group found 20g of whey protein maximized
protein synthesis following unilateral leg extension, 40g significantly outperformed 20g
when the training stimulus was a more strenuous full-body workout. The current study
found that consuming 1.8g/kg of total plant
protein (providing at least 33g of protein at
three of the four meals) was sufficient to induce similar muscle protein synthesis rates
as an omnivorous diet during unilateral leg
extension, but it’s theoretically possible that
modest differences could be observed in the
context of a more challenging training program that targets more musculature.
In summary, it seems like a totally plantbased diet can support hypertrophy goals,
but you might want to make sure you’re
getting at least 35-40g of protein per meal,
double-check the amino acid profiles of
your primary protein sources, and increase
your total daily protein a little bit (let’s say
an additional 0.2-0.3g/kg/day or so, give or
take). If you haven’t seen it yet, Dr. Helms’
two-part video series provides some great
practical tips for making a mostly (or entirely) plant-based diet work for lifters. There
are some additional considerations to keep
in mind, aside from those already listed.
Vegan protein sources generally have more
carbs and fiber compared to animal-based
sources. You’ll notice in the presently reviewed study that the vegan diet group ate
more than twice as much daily fiber than
the omnivorous diet group (68g/day versus 32g/day). Because of the extra fiber and
carbs, it can be hard to eat through fiber’s
satiety-inducing effects while bulking, and
without supplementation it can be hard to
set up a high-protein vegan diet that is low
in calories during weight loss phases. When
it comes to protein sources, a lot of people
fear the potential estrogenic effects of soy
protein; while it doesn’t seem to be a huge
deal when consuming 39.2-78.4g/day (19),
I’m not aware of too many interventions assessing daily intakes much higher than that,
so that might not be a bad daily limit until
more of that research occurs.
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When it comes to mycoprotein, there’s a
heated debate about its safety; the Center for
Science in the Public Interest (CSPI) has been
vocally opposed to mycoprotein’s “generally
recognized as safe” status, and they published
a review of the self-reported adverse events
related to mycoprotein, which included allergic reactions and gastrointestinal symptoms
(20). Some counterpoints (4) are provided by
some folks who, in the interest of full transparency, aren’t exactly unbiased, as the lead
author worked for a company that’s heavily
invested in selling mycoprotein. They argue
that the claims about allergic reactions are
overblown in terms of prevalence and severity, and suggest that many of CSPI’s reported allergic reactions are probably miscategorized cases of gastrointestinal discomfort,
which they attribute to mycoprotein’s high
fiber content. I’m not a food allergy expert,
but I would assume that the lack of action by
multiple government agencies indicates that
the CSPI hasn’t presented a strong enough
case to spur further review of mycoprotein’s
safety or allergy risk. It’s also worth noting
that many foods have the capacity to induce
an allergic response of some magnitude in
susceptible individuals, so the mere possibility of allergic responses does not make a
food inherently dangerous. The presently reviewed study, and several others like it, seem
to be repeatedly conducted without signs of
frequent or disastrous adverse events. Nonetheless, I figured I should at least give MASS
readers the opportunity to look into the controversy if they’re concerned about it. Aside
from those special considerations related to
soy and mycoprotein, protein choice on a
plant-based diet is otherwise guided by di-
gestibility and amino acid composition, and
these two references are great resources for
the amino acid side of the equation.
Next Steps
This is one of those research areas where
we simply need more longitudinal data. I’m
pretty satisfied with the acute and cross-sectional findings in this area, but I’d love to see
more work directly comparing strictly vegan
diets to omnivorous diets over the course of
a rigorous full-body resistance training program. It’d be great to see such a study with
three groups: one consuming 1.8g/kg of protein on an omnivorous diet, one consuming
1.8g/kg on a vegan diet, and the third consuming 2.2g/kg on a vegan diet. This would
help us compare protein-matched vegan
diets to omnivorous diets, while simultaneously assessing the potential benefit of increasing total protein intake to account for
lower-quality protein sources in vegan diets.
If we extrapolate the findings of the presently reviewed study, and assume that these
muscle protein synthesis findings will translate into hypertrophy outcomes that follow
the exact same pattern (which may or may
not be the case), we would theoretically expect similar hypertrophy in all three groups.
However, I wouldn’t totally discount the
possibility that the 1.8g/kg omnivorous diet
might slightly outperform the 1.8g/kg vegan diet, with the extra protein in the 2.2g/kg
diet erasing the difference.
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APPLICATION AND TAKEAWAYS
While plant-based protein sources aren’t the most potent gram-for-gram stimulators
of muscle protein synthesis, their shortcomings can be mitigated by eating sufficient
amounts of total protein, essential amino acids, and leucine. As such, lifters should
have no issues reaching their performance or body composition goals while reducing
or even completely eliminating animal protein sources, provided that their diet is set
up with those key variables in mind. While omnivores in neutral or positive energy
balance tend to optimize lean mass gains with 1.6-2.2g/kg of protein per day, people
who get most (or all) of their protein from plant sources might consider aiming toward
the high end (or even a little bit higher), just to make sure they’ve got their amino acid
bases covered. The current results suggest that it might not be necessary to consume
a little extra protein to account for lower-quality sources, but the downsides of doing
so are limited, and it could potentially be more relevant within the context of a more
potent stimulus for muscle protein synthesis, such as a more rigorous full-body training
program. Given that plant-based protein sources might require slightly higher doses for
an equivalent degree of muscle protein synthesis and generally contain more calories
per gram of protein compared to something like whey isolate or chicken breast, a
strictly vegan diet can admittedly get a bit challenging during weight loss phases
when calories get particularly low. However, that challenge isn’t insurmountable, and
supplementation might be a helpful strategy in that scenario.
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References
1. Monteyne AJ, Dunlop MV, Machin DJ, Coelho MO, Pavis GF, Porter C, et al. A
mycoprotein based high-protein vegan diet supports equivalent daily myofibrillar protein
synthesis rates compared with an isonitrogenous omnivorous diet in older adults: a
randomized controlled trial. Br J Nutr. 2020 Nov 11;1–35.
2. van Vliet S, Burd NA, van Loon LJC. The Skeletal Muscle Anabolic Response to Plantversus Animal-Based Protein Consumption. J Nutr. 2015 Sep;145(9):1981–91.
3. Hoffman JR, Falvo MJ. Protein – Which is Best? J Sports Sci Med. 2004 Sep 1;3(3):118–
30.
4. Finnigan TJA, Wall BT, Wilde PJ, Stephens FB, Taylor SL, Freedman MR. Mycoprotein:
The Future of Nutritious Nonmeat Protein, a Symposium Review. Curr Dev Nutr. 2019
Apr 4;3(6):nzz021.
5. Gorissen SHM, Crombag JJR, Senden JMG, Waterval WAH, Bierau J, Verdijk LB, et
al. Protein content and amino acid composition of commercially available plant-based
protein isolates. Amino Acids. 2018;50(12):1685–95.
6. Asgar MA, Fazilah A, Huda N, Bhat R, Karim AA. Nonmeat Protein Alternatives as
Meat Extenders and Meat Analogs. Compr Rev Food Sci Food Saf. 2010;9(5):513–29.
7. Brennan JL, Keerati-U-Rai M, Yin H, Daoust J, Nonnotte E, Quinquis L, et al.
Differential Responses of Blood Essential Amino Acid Levels Following Ingestion of
High-Quality Plant-Based Protein Blends Compared to Whey Protein-A Double-Blind
Randomized, Cross-Over, Clinical Trial. Nutrients. 2019 Dec 6;11(12).
8. Macnaughton LS, Wardle SL, Witard OC, McGlory C, Hamilton DL, Jeromson S, et
al. The response of muscle protein synthesis following whole‐body resistance exercise
is greater following 40 g than 20 g of ingested whey protein. Physiol Rep. 2016
Aug;4(15):e12893.
9. Volek JS, Volk BM, Gómez AL, Kunces LJ, Kupchak BR, Freidenreich DJ, et al. Whey
protein supplementation during resistance training augments lean body mass. J Am Coll
Nutr. 2013;32(2):122–35.
10. Banaszek A, Townsend JR, Bender D, Vantrease WC, Marshall AC, Johnson KD. The
Effects of Whey vs. Pea Protein on Physical Adaptations Following 8-Weeks of HighIntensity Functional Training (HIFT): A Pilot Study. Sports. 2019 Jan 4;7(1):12.
11. Mobley CB, Haun CT, Roberson PA, Mumford PW, Romero MA, Kephart WC, et al.
Effects of Whey, Soy or Leucine Supplementation with 12 Weeks of Resistance Training
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on Strength, Body Composition, and Skeletal Muscle and Adipose Tissue Histological
Attributes in College-Aged Males. Nutrients. 2017 Sep 4;9(9):972.
12. Brown EC, DiSilvestro RA, Babaknia A, Devor ST. Soy versus whey protein bars:
effects on exercise training impact on lean body mass and antioxidant status. Nutr J. 2004
Dec 8;3:22.
13. Joy JM, Lowery RP, Wilson JM, Purpura M, De Souza EO, Wilson SM, et al. The effects
of 8 weeks of whey or rice protein supplementation on body composition and exercise
performance. Nutr J. 2013 Jun 20;12:86.
14. Gentles JA, Phillips SM. Discrepancies in publications related to HMB-FA and ATP
supplementation. Nutr Metab. 2017 Jul 4;14:42.
15. Phillips SM, Aragon AA, Arciero PJ, Arent SM, Close GL, Hamilton DL, et al. Changes
in body composition and performance with supplemental HMB-FA+ATP. J Strength
Cond Res. 2017;31(5):e71–2.
16. Campbell WW, Barton ML, Cyr-Campbell D, Davey SL, Beard JL, Parise G, et al.
Effects of an omnivorous diet compared with a lactoovovegetarian diet on resistancetraining-induced changes in body composition and skeletal muscle in older men. Am J
Clin Nutr. 1999 Dec;70(6):1032–9.
17. Haub MD, Wells AM, Tarnopolsky MA, Campbell WW. Effect of protein source on
resistive-training-induced changes in body composition and muscle size in older men.
Am J Clin Nutr. 2002 Sep;76(3):511–7.
18. Schoenfeld BJ, Aragon AA, Krieger JW. The effect of protein timing on muscle strength
and hypertrophy: a meta-analysis. J Int Soc Sports Nutr. 2013 Dec 3;10:53.
19. Haun CT, Mobley CB, Vann CG, Romero MA, Roberson PA, Mumford PW, et al.
Soy protein supplementation is not androgenic or estrogenic in college-aged men when
combined with resistance exercise training. Sci Rep. 2018 24;8(1):11151.
20. Jacobson MF, DePorter J. Self-reported adverse reactions associated with mycoprotein
(Quorn-brand) containing foods. Ann Allergy Asthma Immunol. 2018;120(6):626–30.
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Study Reviewed: Prediction of Muscle Fiber Composition Using Multiple Repetition Testing.
Hall et al. (2020)
Can We Predict Muscle Fiber Type
Distributions from Rep Max Tests?
BY GREG NUCKOLS
It’s commonly believed that people with greater strength
endurance have a greater proportion of slow-twitch muscle fibers,
and that people with worse strength endurance have a greater
proportion of fast-twitch fibers. A recent study examined this
belief, and found that it contains a grain of truth … but only a grain.
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KEY POINTS
1. 30 trained subjects (20 males and 10 females) performed a set of squats to
failure at 80% of 1RM and had their vastus laterali biopsied to assess muscle
fiber type composition.
2. Reps completed during the set to failure were inversely associated with the
subjects’ relative proportion of type II fibers. In other words, subjects with
a greater proportion of type II fibers completed fewer reps during the set to
failure, and subjects with a greater proportion of type I fibers completed more
reps during the set to failure.
3. However, the association was fairly weak (ρ = -0.38), so a reps-to-failure test
still isn’t a reliable way to predict fiber type proportions within an individual.
It’s been proposed that you can predict someone’s muscle fiber type distribution, with
enough accuracy to be useful, by simply having them perform a rep max test. If they can’t
complete many reps at a given percentage of
their 1RM, you can deduce that they have a
higher percentage of type II (“fast-twitch”)
fibers, while if they can complete a lot of
reps, they likely have a higher proportion of
type I (“slow-twitch”) fibers. This idea was
popularized in the literature by Karp (2), and
in the broader fitness industry by Fred Hatfield and Charles Poliquin. It’s certainly an
intuitive idea: Type II fibers are inherently
more fatigable than type I fibers, so it makes
sense that people with a larger proportion of
type II fibers would fail sooner than people
with a larger proportion of type I fibers when
performing a set to failure on a given exercise with a given percentage of their 1RM.
However, we can’t simply accept something
as true just because it makes intuitive sense;
we need experimental evidence.
The presently reviewed study (1) tested this
idea in 30 subjects (20 males and 10 females)
with at least two years of prior training experience. Biopsies were performed to assess the
muscle fiber type composition of their vastus
laterali, and they performed one set of squats
to failure at 80% of 1RM. The number of
reps completed during the set to failure was
negatively associated with the subjects’ proportion of type II fibers (ρ = -0.38), but the
relationship was too weak to afford us with
much predictive validity from this test. Thus,
while fiber type composition may be associated with single-set strength endurance, we
can’t predict fiber type composition from a
reps to failure test with enough accuracy for
our predictions to be particularly useful.
Purpose and Hypotheses
Purpose
The purpose of the study was to investigate
the association between vastus lateralis muscle fiber composition and squat repetitions to
failure at 80% of 1RM.
102
Hypotheses
The authors hypothesized that the number of
squat reps completed at 80% of 1RM would
be inversely correlated with the proportion
of type II fibers the subjects possessed (e.g.
people who had a higher proportion of type
II fibers would complete fewer reps, and vice
versa).
Subjects and Methods
Subjects
30 subjects, including 10 females and 20
males, completed this study. They were all
between 18 and 40 years old, and had at least
2 years of experience with the back squat. 10
of the males and 7 of the females described
their training background as including a mix
of both resistance training and aerobic train-
ing, while 10 males and 3 females reported
a background consisting solely of resistance
training. More information about the subjects
can be seen in Table 1.
Experimental Design
All subjects completed the study in one session. Subjects completed a 1RM testing protocol for the back squat. Following 15 minutes of rest, they completed as many reps as
they could with 80% of their newly established 1RMs.
All squats were performed with a low bar
position, depth was standardized (tops of
the thighs parallel to the floor), and the researchers attempted to standardize rep cadence (two-second eccentric, one-second
concentric). It’s not clear exactly what steps
were taken to standardize rep cadence and
depth, however.
103
Muscle fiber composition of the vastus lateralis was assessed via biopsy and antibody
staining. Muscle fiber cross-sectional areas
were also assessed from the biopsies.
Findings
The range of repetitions completed with
80% of 1RM spanned from 5-15 reps. Percentage of type II fibers was inversely associated with the number of reps completed
at 80% of 1RM, using Spearman correlation
(ρ = -0.38, p = 0.039). No other measured
variable (age, sex, 1RM strength, training
frequency, training experience, whether the
subjects performed aerobic training, BMI,
and muscle fiber cross-sectional area) was
associated with the number of reps performed at 80% of 1RM.
Subjects who completed 5-8 reps had a significantly greater proportion of type II fibers than subjects who completed 11-15 reps
(57.5 ± 9.5% vs. 44.4 ± 11.9%; p = 0.013).
The subjects who completed 9 or 10 reps had
roughly equal proportions of type I (50.8 ±
16.9%) and type II (51.6 ± 17.5%) fibers.
Criticisms and Statistical
Musings
This doesn’t fundamentally change the interpretation of the results, but the authors’
choice of statistical test in the present study
was … unorthodox, to say the least.
There are three primary types of regression
analysis used in exercise science: Pearson regression, Spearman regression, and logistic
104
regression (logistic regression isn’t relevant
for our purposes here). Pearson regression is
most common (if you see someone report an
r-value, they generally used Pearson regres-
sion), for good reason. It’s used when examining the relationship between two variables
that are composed of interval or ratio data,
and both are approximately normally distrib-
105
uted (which most human data tends to be;
also, categorical data can be dummy coded
and used in Pearson regression). Interval or
ratio data include reps performed in a set, kilograms of lean mass, grams of carbohydrate
consumed, etc. When data isn’t normally
distributed, or when you’re dealing with ordinal data, you might use Spearman regression, which transforms interval or ratio data
into ordinal data by rank-ordering it, and then
runs regression analysis on the ranks.
Here’s an illustration of the difference between Pearson regression and Spearman
regression: let’s say you want to know the
relationship between free-throw shooting
accuracy and three-point shooting accuracy
in the NBA. If you used Pearson regression,
you could simply plot free-throw shooting
accuracy (as a percentage) on the x-axis and
three-point shooting accuracy on the y-axis
for each player, then find the resultant trendline (and p-value, if you wanted to). If you
used Spearman regression, you’d plot the
player’s free-throw shooting rank on the
x-axis (the most accurate shooter would be
“1”, and second most accurate would be “2”,
etc.) and their three-point shooting rank on
the y-axis, and then find the resultant trendline (and p-value, if you wanted to).
In this case, the correlation coefficient isn’t
drastically different (r = 0.45 for Pearson regression, and p = 0.44 for Spearman regression), but the graphs clearly illustrate how
the data differ between these two types of
analyses. A key difference is that you lose a
lot of information when you use Spearman
regression. The trendline with Pearson regression has an equation with a useful liter-
al interpretation: If you plug a player’s free
throw percentage (as a decimal) in for “x” in
the equation, you can predict their three-point
percentage. In the case of Spearman regression, you’d plug in the player’s free throw
shooting rank, and predict their three-point
shooting rank. If you wanted to do something
useful with the insights from your analysis,
“based on this player’s 81% free throw accuracy, I predict they could become a 36%
three-point shooter” is more useful than,
“based on the fact that this player is the 32nd
best free throw shooter, I predict they could
become the 85th best three-point shooter,”
or something of that nature. Basically, when
you’re justified in using Pearson regression
(your data aren’t significantly non-normal,
and you’re dealing with interval or ratio
data), it’s almost always better to use Pearson regression; Spearman regression should
generally only be used when your data are
significantly non-normal, or when you’re already working with ordinal data.
With that in mind, it’s really weird that the
authors of the present study used Spearman
regression for ascertaining the relationship between type II fiber percentage and reps completed with 80% of 1RM. I extracted the data
from Figure 1 using WebPlotDigitizer to make
sure it wasn’t significantly non-normal using
the Shapiro-Wilk test (it wasn’t). Furthermore,
type II fiber percentage and reps completed are
ratio data, so Pearson regression is the clear regression choice for this study.
On the bright side, since I could extract that
data, I was able to calculate the r-value and
p-value using Pearson regression. After doing so, I think I know why the authors de-
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cided to use Spearman’ regression instead.
Using Pearson correlation doesn’t change the
correlation coefficient very much (r = -0.34
instead of ρ = -0.38); however, the slight reduction in correlation coefficient changes
the p-value from “significant” (p = 0.039) to
non-significant (p = 0.070). To be charitable,
there’s a possibility that I made a mistake
when extracting the data, and there’s a possibility that the authors made an a priori decision to use Spearman regression (maybe they
anticipated that one of their variables would
be non-normal or had some other justification), but my knee-jerk reaction is that this
looks a lot like p-hacking (finding a statistical test that will get you a significant p-value, rather than choosing the most appropriate
statistical test for your data).
To be clear, that doesn’t actually change my
interpretation of these results. In practical
terms, I wouldn’t interpret a correlation coefficient of -0.34 differently from a correlation
coefficient of -0.38, and the “significance”
threshold is fairly arbitrary anyways. I mostly
wanted to point this out so you can be vigilant
about it when reading research for yourself.
Interpretation
This is the fourth time in recent months that
I’ve reviewed a study related to the effects of
fiber types on some sort of practical training
outcome. One study found that people with
a greater proportion of type II fibers take
longer to recover after a fatiguing exercise
bout (3), one found that people with a greater
proportion of type II fibers may be at greater
risk of overreaching when increasing training volume (4), and one found that fiber type
proportions aren’t a significant predictor of
powerlifting performance (5).
The present study (1) adds to those previous
findings, suggesting that differences in fiber
type distributions may be predictive of acute
strength endurance in the squat. However, I
think this study is a clear example of the fact
that a (possibly) significant finding may not
necessarily be a predictive finding. In other
words, there may truly be a relationship between squat reps completed at 80% of 1RM
and relative fiber type proportions, but that
relationship is too weak to serve as a useful
predictor for individuals.
For example, if we used the cutoffs proposed
in the present study (< 9 reps indicates a larger proportion of type II fibers, > 10 reps indicates a larger proportion of type I fibers,
and 9-10 reps indicates similar proportions
of type I and type II fibers, which I’ll operationally define as 50 ± 10% type II fibers),
we’d make bad predictions about the fiber
I THINK THIS STUDY IS A
CLEAR EXAMPLE OF THE
FACT THAT A SIGNIFICANT
FINDING MAY NOT
NECESSARILY BE A
PREDICTIVE FINDING.
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type composition of a lot of the individual
subjects. Approximately 30% of the subjects
who completed 5-8 reps had more than 50%
type II fibers in their vastus lateralis, and approximately 30% of the subjects who completed 11+ reps had less than 50% type II fibers. Meanwhile, the subjects that completed
9-10 reps include the subject with the lowest
proportion of type II fibers (~28%) and the
subject with the highest proportion of type
II fibers (~81%), and half had either > 60%
type II fibers or < 40% type II fibers. Put all
of that together, and if you used this test as a
screening tool for yourself or your clients – if
they completed 11+ reps, you’d assume they
were type I dominant, if they completed fewer than 9 reps, you’d assume they were type
II dominant, and if they completed 9-10 reps,
you’d assume they had roughly equal proportions of both fiber types – you’d be wrong
approximately one-third of the time. That’s
still better than a coin flip, but it doesn’t provide us with enough predictive ability to be
particularly useful, in my opinion.
In fact, further confounders make it even more
challenging to apply the results of the present
study to the weight room. For starters, squats
were the only exercise tested. We know that
the number of reps that can be completed with
a particular percentage of 1RM varies considerably between exercises. In other words,
completing seven squat reps with 80% of
1RM may be weakly predictive of having a
greater proportion of type II fibers, but completing seven reps in the deadlift may be predictive of having a roughly equal proportion
of both fiber types. We also can’t generalize
beyond 80% of 1RM as a testing load. This
same type of relationship still likely exists if
you wanted to test strength endurance with
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some other percentage of 1RM, but we don’t
know what rep thresholds would correspond
with predictions of a high or low proportion
of type II fibers. Finally, it’s likely that the association between fiber type proportions and
reps completed at a given percentage of 1RM
would be even weaker in practice. In the present study, squat depth and rep cadence were
said to be standardized. When left to their
own devices, however, people may squat to
different depths, or use dramatically different
rep cadences (which would affect total time
under tension, and could thus affect the total
number of reps people could complete before
fatiguing). Introducing additional confounders tends to weaken correlations.
a relatively high proportion of 1RM, most
people are likely to fail when a fairly modest amount of their type II fibers accumulate
sufficient fatigue. At 80% of 1RM, you need
to be able to maintain at least 80% of maximal force output to complete each rep. So, if
about 20% of your force is produced by about
10% of your motor units (your largest type II
motor units), as soon as those 10% of motor
units fatigue and start producing dramatically
less force during a set, you’re in hot water.
Thus, as long as someone doesn’t just have a
ludicrously small proportion of type II fibers,
they’ll probably be limited by the fatigue of
their largest, most fatigable type II motor
units, just like everyone else.
At this point you may be wondering why
fiber types aren’t super strongly associated
with strength endurance. After all, type I fibers are less fatigable than type II fibers, so
people with a greater proportion of type I fibers should be able to complete more reps before tiring out, right? I think the explanation
is pretty simple: there are simply other factors in play. For example, squat range of motion naturally varies between people, based
on height, limb lengths, and stance width.
People who move each rep through a longer
range of motion will need to expend more
energy per rep, because they’re completing
more mechanical work per rep, all else equal.
Capillarization or mitochondrial density may
matter (both of which are associated with
fiber type proportions, though those aren’t
a 1:1 relationship). Habitual training style
probably matters as well – higher-rep training is known to improve strength endurance.
Finally, when testing strength endurance with
Also note, this isn’t the first study that failed
to find a strong relationship between fiber
type proportions and strength endurance
during resistance training. Back in 2008,
Terzis and colleagues found that fiber type
proportions weren’t significantly related to
leg press reps to failure with 70% and 85%
of 1RM (6; 10). However, they did find that
capillary density (capillaries per square mm
of muscle cross-sectional area) was significantly associated with reps to failure at 70%
of 1RM. On the other hand, Douris and colleagues did find an inverse relationship (r
= -0.48; p = 0.02) between knee extension
reps completed at 70% of 1RM and estimated proportion of type II fibers (7). However,
fiber type proportions were estimated by using what amounted to a strength endurance
test: measures of force reduction following
55 high-velocity knee extension reps on an
isokinetic dynamometer. In other words, the
Douris study essentially found that one mea-
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THIS ISN’T THE FIRST
STUDY THAT FAILED
TO FIND A STRONG
RELATIONSHIP
BETWEEN FIBER
TYPE PROPORTIONS
AND STRENGTH
ENDURANCE DURING
RESISTANCE TRAINING.
sure of knee extension strength endurance
(reps to failure at 70% of 1RM) was associated with another measure of knee extension
strength endurance (decrements in force after
55 high-velocity reps); the researchers never actually measured fiber type proportions
in the subjects. When considering both the
present study and the study by Terzis and
colleagues, it appears that if fiber type proportions are related to single-set strength endurance, that relationship is very weak and
not very predictive.
Finally, I wanted to point out one interesting
observation in the present study: 17 out of 30
subjects habitually performed both aerobic
and resistance training, while 13 only did re-
sistance training. The authors report that the
subjects’ training backgrounds weren’t predictive of reps-to-failure performance. In previous research, we’ve seen aerobically trained
subjects complete way more reps to failure
than strength-trained subjects. For example,
a study by Richens and Cleather found that
strength-trained subjects completed an average of about 18 reps to failure on the leg press
with 70% of 1RM, while endurance-trained
subjects completed an average of about 40
reps (8). Similarly, another study by Panissa
and colleagues found that endurance-trained
subjects completed more reps than resistance-trained subjects across four sets of half
squats at 80% of 1RM (9). However, in the
same study, there wasn’t a significant difference in reps completed between the strengthtrained subjects and a third group with both
strength and endurance training experience
(47 reps for the endurance-trained subjects,
32 reps for the strength-trained subjects, and
35 reps for the subjects with a mixed training
background). Thus, the present study and the
Panissa study both suggest that doing some
endurance training is unlikely to improve
strength endurance in people who are also
engaged in resistance training, though people
who only perform endurance training tend to
have considerably greater strength endurance
than people who engage in resistance training. I’m not surprised that people with only
an endurance training background can complete a ton of reps – their 1RM is probably
lower than it “should” be (since they won’t
have the motor skills necessary for a truly
representative 1RM test, just like anyone else
who lacks resistance training experience).
Furthermore, they’re generally going to be
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quite weak, and the resulting submaximal
loads may be low enough that their peripheral aerobic adaptations can make a huge difference in rep performance. However, I am a
bit surprised to see that subjects who perform
both strength and aerobic training aren’t able
to perform more reps to failure with a fixed
percentage of 1RM than subjects who only
engage in resistance training. I’d anticipate
that peripheral aerobic adaptations (such as
enhanced capillary density and mitochondrial density and efficiency) would have at least
some positive impact. Perhaps the difference
isn’t meaningful with higher loads (the present study and the Panissa study both used
80% of 1RM), but would be larger with low-
MUSCLE FIBER TYPE
DISTRIBUTIONS MAY
BE ASSOCIATED WITH
LOWER BODY STRENGTH
ENDURANCE TO SOME
DEGREE, BUT THE
ASSOCIATION IS TOO
WEAK TO RELIABLY PREDICT
SOMEONE’S FIBER TYPE
DISTRIBUTION USING
REPS-TO-FAILURE TESTS.
er loads. At minimum, I’d love to see more
research on the topic.
To wrap things up, muscle fiber type distributions may be associated with lower body
strength endurance to some degree, but the
association is too weak to reliably predict
someone’s fiber type distribution using repsto-failure tests. As we’ve previously discussed in MASS, you probably don’t need
to be particularly worried about your fiber
type distribution for strength or hypertrophy
goals, but if you were interested in learning more about your fiber type distribution
to plan recovery times or get an idea of how
conservative you should be when ramping up
training loads, biopsies are still the gold standard. Non-invasive muscle carnosine scans
are also a promising alternative, but that technology isn’t widely available yet. So, for all
intents and purposes, we still don’t have a
cheap, non-invasive, reliable method of determining muscle fiber composition.
Next Steps
As a final effort to save this line of research,
a future study could repeat the same design
of the present study, but assess strength endurance using a single-joint movement (like
knee extensions) where systemic metabolic
fatigue would be lower, and exercise kinematics would be easier to perfectly standardize. If
that study also found either no relationship or
a weak relationship between fiber type distributions and rep performance during a set to
failure, I would say that it’s probably time to
call it quits on this line of research. Based on
similar research using isokinetic testing, I’m
not optimistic that the proposed study would
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APPLICATION AND TAKEAWAYS
You can’t predict your fiber type proportions via your performance on a reps-tofailure test with enough accuracy or precision for your predictions to be useful.
find a relationship between strength endurance
and fiber type distributions (11), but it’s probably the best chance we have for identifying
a non-invasive test of fiber type distributions
that can be done in a normal gym setting.
112
References
1. Hall E, Lysenko E, Semenova E, Borisov O, Andryushchenko O, Andryushchenko L,
Vepkhvadze T, Lednev E, Zmijewski P, Popov D, Generozov E, Ahmetov I. Prediction
of muscle fiber composition using multiple repetition testing. Biology of Sport.
2020:277-283. doi:10.5114/biolsport.2021.99705.
2. Karp JR. Muscle fiber types and training. Strength Cond Jour. 2001 Oct;23(5):21-26.
3. Lievens E, Klass M, Bex T, Derave W. Muscle fiber typology substantially influences
time to recover from high-intensity exercise. J Appl Physiol (1985). 2020 Mar
1;128(3):648-659. doi: 10.1152/japplphysiol.00636.2019. Epub 2020 Jan 30. PMID:
31999527.
4. Bellinger P, Desbrow B, Derave W, Lievens E, Irwin C, Sabapathy S, Kennedy B,
Craven J, Pennell E, Rice H, Minahan C. Muscle fiber typology is associated with the
incidence of overreaching in response to overload training. J Appl Physiol (1985). 2020
Oct 1;129(4):823-836. doi: 10.1152/japplphysiol.00314.2020. Epub 2020 Aug 20. PMID:
32816636.
5. Machek SB, Hwang PS, Cardaci TD, Wilburn DT, Bagley JR, Blake DT, Galpin
AJ, Willoughby DS. Myosin Heavy Chain Composition, Creatine Analogues, and
the Relationship of Muscle Creatine Content and Fast-Twitch Proportion to Wilks
Coefficient in Powerlifters. J Strength Cond Res. 2020 Aug 27. doi: 10.1519/
JSC.0000000000003804. Epub ahead of print. PMID: 32868674.
6. Terzis G, Spengos K, Manta P, Sarris N, Georgiadis G. Fiber type composition and
capillary density in relation to submaximal number of repetitions in resistance exercise.
J Strength Cond Res. 2008 May;22(3):845-50. doi: 10.1519/JSC.0b013e31816a5ee4.
PMID: 18438231.
7. Douris PC, White BP, Cullen RR, Keltz WE, Meli J, Mondiello DM, Wenger D. The
relationship between maximal repetition performance and muscle fiber type as estimated
by noninvasive technique in the quadriceps of untrained women. J Strength Cond Res.
2006 Aug;20(3):699-703. doi: 10.1519/17204.1. PMID: 16937985.
8. Richens B, Cleather DJ. The relationship between the number of repetitions performed at
given intensities is different in endurance and strength trained athletes. Biol Sport. 2014
Jun;31(2):157-61. doi: 10.5604/20831862.1099047. Epub 2014 Apr 5. PMID: 24899782;
PMCID: PMC4042664.
9. Panissa VL, Azevedo NR, Julio UF, Andreato LV, Pinto E Silva CM, Hardt F, Franchini
E. Maximum number of repetitions, total weight lifted and neuromuscular fatigue
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in individuals with different training backgrounds. Biol Sport. 2013 Jun;30(2):1316. doi: 10.5604/20831862.1044458. Epub 2013 Apr 11. PMID: 24744479; PMCID:
PMC3944574.
10. One possible complaint about the present study by Hall and colleagues is that the low bar
squat was the exercise used for testing. For some subjects, strength endurance of the hip
extensors may be more predictive of reps to failure than strength endurance of the quads
(which were the only muscle biopsied). However, that’s less of a concern in the Terzis
study, which used the leg press – leg press performance should be pretty well-constrained
by quad strength and quad strength endurance.
11. Bagley JR, McLeland KA, Arevalo JA, Brown LE, Coburn JW, Galpin AJ. Skeletal
Muscle Fatigability and Myosin Heavy Chain Fiber Type in Resistance Trained Men.
J Strength Cond Res. 2017 Mar;31(3):602-607. doi: 10.1519/JSC.0000000000001759.
PMID: 27984439.
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VIDEO: Accentuated Eccentrics
BY MICHAEL C. ZOURDOS
The effectiveness of overloading your eccentrics to improve concentric
outcomes is equivocal. However, new data suggest the concentric load may
be a pivotal factor in determining if accentuated eccentrics are effective. This
video examines the landscape of accentuated eccentrics to enhance strength
and provides insight into the new data.
Click to watch Michael's presentation.
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Relevant MASS Videos and Articles
1. Accentuated Eccentric Loading for Hypertrophy, Strength, and Power. Volume 1 Issue 6.
2. Can You Build More Size and Strength with Overloaded Eccentrics? Volume 2 Issue 10.
3. VIDEO: Eccentric Duration Training. Volume 4 Issue 6.
References
1. Katz B. The relation between force and speed in muscular contraction. The Journal of
Physiology. 1939 Jun 14;96(1):45.
2. Schoenfeld BJ, Ogborn DI, Vigotsky AD, Franchi MV, Krieger JW. Hypertrophic effects of
concentric vs. eccentric muscle actions: a systematic review and meta-analysis. The Journal of
Strength & Conditioning Research. 2017 Sep 1;31(9):2599-608.
3. Flann KL, LaStayo PC, McClain DA, Hazel M, Lindstedt SL. Muscle damage and muscle
remodeling: no pain, no gain?. Journal of Experimental Biology. 2011 Feb 15;214(4):674-9.
4. Damas F, Phillips SM, Libardi CA, Vechin FC, Lixandrão ME, Jannig PR, Costa LA, Bacurau
AV, Snijders T, Parise G, Tricoli V. Resistance training-induced changes in integrated
myofibrillar protein synthesis are related to hypertrophy only after attenuation of muscle
damage. The Journal of physiology. 2016 Sep 15;594(18):5209-22.
5. Buskard AN, Gregg HR, Ahn S. Supramaximal eccentrics versus traditional loading in
improving lower-body 1RM: A meta-analysis. Research Quarterly for Exercise and Sport. 2018
Jul 3;89(3):340-6.
6. Cook CJ, Beaven CM, Kilduff LP. Three weeks of eccentric training combined with overspeed
exercises enhances power and running speed performance gains in trained athletes. The Journal
of Strength & Conditioning Research. 2013 May 1;27(5):1280-6.
7. Yarrow JF, Borsa PA, Borst SE, Sitren HS, Stevens BR, White LJ. Early-phase neuroendocrine
responses and strength adaptations following eccentric-enhanced resistance training. The Journal
of Strength & Conditioning Research. 2008 Jul 1;22(4):1205-14.
8. Godard MP, Wygand JW, Carpinelli RN, Catalano S, Otto RM. Effects of accentuated eccentric
resistance training on concentric knee extensor strength. The Journal of Strength & Conditioning
Research. 1998 Feb 1;12(1):26-9.
9. Walker S, Häkkinen K, Haff GG, Blazevich AJ, Newton RU. Acute elevations in serum
hormones are attenuated after chronic training with traditional isoinertial but not accentuated
eccentric loads in strength-trained men. Physiological Reports. 2017 Apr;5(7):e13241.
10. Douglas J, Pearson S, Ross A, McGuigan M. Effects of accentuated eccentric loading on muscle
properties, strength, power, and speed in resistance-trained rugby players. The Journal of
Strength & Conditioning Research. 2018 Oct 1;32(10):2750-61.
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11. Doan BK, Newton RU, Marist JL, Triplett-McBride NT, Koziris LP, Fry AC, Kraemer
WJ. Effects of increased eccentric loading on bench press 1RM. The Journal of Strength &
Conditioning Research. 2002 Feb 1;16(1):9-13.
12. Ojasto T, Häkkinen K. Effects of different accentuated eccentric load levels in eccentricconcentric actions on acute neuromuscular, maximal force, and power responses. The Journal of
Strength & Conditioning Research. 2009 May 1;23(3):996-1004.
13. Merrigan JJ, Tufano JJ, Falzone M, Jones MT. Effectiveness of Accentuated Eccentric Loading:
Contingent on Concentric Load. International Journal of Sports Physiology and Performance.
2020 Nov 12;1(aop):1-7.
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VIDEO: Pros and Cons of Body
Composition Testing
BY ERIC HELMS
Wouldn’t it be great if you had a DXA scanner at home so you could ditch the
scale and mirror and get a weekly scan to assess progress? Actually, it wouldn’t
be great; it would lead you astray to get scanned that frequently. In this video
you’ll learn the difference between the perception and the data on the precision
of the most common body composition assessment devices and you’ll learn
how, and how often it’s reasonable to get tested.
Click to watch Eric's presentation.
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References
1. Meyer NL, Sundgot-Borgen J, Lohman TG, Ackland TR, Stewart AD, Maughan RJ, Smith
S, Müller W. Body composition for health and performance: a survey of body composition
assessment practice carried out by the Ad Hoc Research Working Group on Body Composition,
Health and Performance under the auspices of the IOC Medical Commission. Br J Sports Med.
2013 Nov;47(16):1044-53.
2. Hangartner TN, Warner S, Braillon P, Jankowski L, Shepherd J. The Official Positions of the
International Society for Clinical Densitometry: acquisition of dual-energy X-ray absorptiometry
body composition and considerations regarding analysis and repeatability of measures. J Clin
Densitom. 2013 Oct-Dec;16(4):520-36.
3. Nelson L, Gulenchyn KY, Atthey M, Webber CE. Is a fixed value for the least significant
change appropriate? J Clin Densitom. 2010 Jan-Mar;13(1):18-23.
4. Farley A, Slater GJ, Hind K. Short-Term Precision Error of Body Composition Assessment
Methods in Resistance-Trained Male Athletes. Int J Sport Nutr Exerc Metab. 2020 Nov 12:1-11.
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119
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. Deshayes et al. “Not performing worse but feeling older !” the negative effect of the
induction of a negative aging stereotype
2. Kopp et al. Achievement motive, autonomous motivation, and attendance at fitness
center: A longitudinal prospective study
3. Goršič et al. Biomechanical comparisons of back and front squats with a straight bar and
four squats with a transformer bar
4. Wortman et al. Blood Flow Restriction Training for Athletes: A Systematic Review
5. Krzysztofik et al. Can the Cambered Bar Enhance Acute Performance in the Bench Press
Exercise?
6. Fukutani et al. Differences in stretch-shortening cycle and residual force enhancement
between muscles
7. Tagawa et al. Dose–response relationship between protein intake and muscle mass
increase: a systematic review and meta-analysis of randomized controlled trials
8. Pureza et al. Effect of early time-restricted feeding on the metabolic profile of adults with
excess weight: A systematic review with meta-analysis
9. Parahiba et al. Effect of testosterone supplementation on sarcopenic components in
middle-aged and elderly men: A systematic review and meta-analysis
10. Moran et al. Effects of Bilateral and Unilateral Resistance Training on Horizontally
Orientated Movement Performance: A Systematic Review and Meta-analysis
11. Prowting et al. Effects of Collagen Peptides on Recovery Following Eccentric Exercise in
Resistance-Trained Males-A Pilot Study
12. Travis et al. Emphasizing Task-Specific Hypertrophy to Enhance Sequential Strength and
Power Performance
13. Oxfeldt et al. Hormonal Contraceptive Use, Menstrual Dysfunctions, and Self-Reported
Side Effects in Elite Athletes in Denmark
14. Clark et al. Impact of resistance training status on trunk muscle activation in a fatiguing
set of heavy back squats
15. Bini et al. Lower limb muscle and joint forces during front and back squats performed on
a smith machine
16. Schiaffino et al. Molecular Mechanisms of Skeletal Muscle Hypertrophy
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17. Kipp et al. Muscle-Specific Contributions to Lower Extremity Net Joint Moments While
Squatting With Different External Loads
18. Garbisu-Hualde and Santos Concejero. Post-activation potentiation in strength training: A
systematic review of the scientific literature
19. Mercer et al. Protein Requirements of Pre-Menopausal Female Athletes: Systematic
Literature Review
20. Heileson and Funderburk. The effect of fish oil supplementation on the promotion and
preservation of lean body mass, strength, and recovery from physiological stress in young,
healthy adults: a systematic review
21. Wetmore et al. The Effect of Training Status on Adaptations to 11 Weeks of Block Periodization
Training
22. Malta et al. The Effects of Regular Cold-Water Immersion Use on Training-Induced Changes
in Strength and Endurance Performance: A Systematic Review with Meta-Analysis
23. Coratella et al. The Effects of Verbal Instructions on Lower Limb Muscles’ Excitation in
Back-Squat
24. Alves et al. Training Programs Designed for Muscle Hypertrophy in Bodybuilders: A Narrative
Review
25. Travis et al. Weight Selection Attempts of Elite Classic Powerlifters
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Thanks for
reading MASS.
The next issue will be released to
subscribers on February 1, 2021.
Graphics and layout by Kat Whitfield
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