V O L U ME 4 , ISS U E 2
FEBRUA RY 2 0 2 0
MASS
M ONTHLY A PPL ICATIO N S IN
STRE N G TH SPO R T
E R IC 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. Eric regularly publishes peer-reviewed
articles in exercise science and nutrition journals on physique and strength sport, in addition to writing for
commercial fitness publications. He’s taught undergraduate- and graduate-level nutrition and exercise
science and speaks internationally at academic and commercial conferences. He has a B.S. in fitness
and wellness, an M.S. in exercise science, a second Master’s in sports nutrition, a Ph.D. in strength and
conditioning, and is a research fellow for the Sports Performance Research Institute New Zealand at
Auckland University of Technology. Eric earned pro status as a natural bodybuilder with the PNBA in 2011 and competes in the
IPF at international-level events as an unequipped powerlifter.
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.
2
Letter from
the Reviewers
W
elcome to the February issue of MASS! As always, we have a great issue for
you this month. Dr. Zourdos breaks down the most recent volume study, the first
published study examining the effects of knee sleeves on squatting kinetics and
kinematics, and he covers full-body programming in his video this month. Dr. Helms wrote
his article about oral ATP supplementation, and continued his video series on post-contest
nutrition strategies. Greg covered a study comparing the effects of resistance training and
impact loading on bone adaptations, a paper examining whether ribosome biogenesis could
explain why some people respond well to higher training volumes while others don’t, and
a paper fleshing out the relationship between muscle size and force production. Finally, Dr.
Trexler’s articles covered vitamin D supplementation for lifters and capsaicin supplementation.
As a quick announcement before we get into the issue: this may be our final letter from
the reviewers. The letter is essentially just an introduction to the topics we’re going to cover
in the issue, which is already accomplished by the table of contents. We’re deciding what to
replace it with, but whatever direction we go, we want it to be something that’s more valuable for all of you. If you have any suggestions or strong opinions, feel free to share them
in the Facebook group.
Sincerely,
The MASS Team
Eric Helms, Greg Nuckols, Mike Zourdos, and Eric Trexler
3
Table of Contents
6
BY G R EG NUCKOL S
Training for Bone Health
Here at MASS, we’re obviously focused on making muscles bigger and stronger. But what about the
skeleton? Osteopenia and osteoporosis place a huge burden on millions of people as they age. If you
want to maximize bone health, are you better off with heavy resistance training or impact loading? Read
on to find out.
18
BY M I CHAEL C. ZOUR DOS
Bring the Full Court Press: Evidence for Really High Volumes
There is an increasing interest in how many sets per week should be performed to maximize
hypertrophy and strength. This study shows support for 30+ sets; however, there is much more to
discuss. Sit back and get ready for a comprehensive look at set volume needs.
38
BY E RI C HEL MS
Oral ATP Supplementation May Enhance Performance, Albeit Indirectly
Until now, the case for oral ATP as an ergogenic aid was weak. Small sample studies have either found
no positive effects, found benefits but were methodologically questionable, or found effects that were
inconsistent and small. Most problematic are data suggesting that ATP is not orally bioavailable. So
how did oral ATP enhance performance in this study? Read on to find out.
52
BY E R I C T R EXL ER
Shedding Some Light on Vitamin D Supplementation: Does It
Increase Strength In Athletes?
Vitamin D deficiency is shockingly common in athletes, and low levels are associated with reduced
strength. A recent meta-analysis suggested that vitamin D supplementation failed to enhance
strength in athletes, but there’s more to this paper than meets the eye. Read on to figure out if
vitamin D supplementation might be worth considering.
65
BY G R EG NUCKOL S
Ribosome Biogenesis Influences Whether High Volumes Cause More
Growth
Higher volumes tend to lead to more muscle growth and larger strength gains, but not everyone
responds to higher volumes in the same way. A recent study found that people who respond better
to higher volumes may do so due to an increase in ribosomal content of their muscle fibers.
4
77
88
BY M I CHAEL C. ZOUR DOS
Are Knee Sleeves or Knee Wraps Right for You?
We know that knee wraps may help you lift more, but what about knee sleeves? And, how do
both of these acutely affect squat biomechanics? This article answers some of those questions
and discusses when sleeves and wraps are appropriate outside of the typical powerlifting
context.
BY E R I C T R EXL ER
The Hottest Supplement on the Market: New Research on Capsaicin
and Strength
Back in Volume 1, Dr. Helms covered one of the first studies evaluating capsaicin’s effects on lifting
performance. Another one is finally here, with results suggesting that capsaicin increases squatting
strength endurance following high-intensity running. Read on to find out if capsaicin supplementation
might be worth a try.
98
BY G R EG NUCKOL S
Simplified Strength Tests Reveal the True Importance of Muscle Size
for Force Output
In a max squat, there are a lot of moving parts … literally. When we strip away as much of the skill
component as possible to simply measure sheer muscular force output, we see that trained lifters
produce more force than untrained lifters almost entirely due to the fact that their muscles are larger.
109
111
BY M I CHAEL C. ZOUR DOS
VIDEO: Setting Up Full-Body Training
It can be challenging to set up a full-body training program that effectively manages fatigue. This
video shows you how to do that, while examining the unique ability of high frequency full-body
training weeks to allow for volume cycling between upper and lower body muscle groups.
BY E RI C HEL MS
VIDEO: Post-Season Nutrition Strategies, Part 2
In part 1 of this series, we modeled “metabolic adaptation” during contest preparation to explain
what occurs and why. Also, we covered how “reverse dieting” impacts outcomes. In part 2, we dive
into the scant but relevant research pertaining to reverse and “recovery” diets to discuss the aspects
which should be considered from a broad, biopsychosocial perspective.
5
Study Reviewed: Regional Changes in Indices of Bone Strength of Upper and Lower
Limbs in Response to High-Intensity Impact Loading or High-Intensity Resistance Training.
Lambert et al. (2019)
Training for Bone Health
BY G RE G NUC KO LS
Here at MASS, we’re obviously focused on making muscles bigger and
stronger. But what about the skeleton? Osteopenia and osteoporosis place a
huge burden on millions of people as they age. If you want to maximize bone
health, are you better off with heavy resistance training or impact loading?
Read on to find out.
6
KEY POINTS
1. Female subjects with below-average bone health (mass and density) trained for
10 months, performing either an impact loading program (consisting of punching,
jumping, and plyometrics) or a heavy resistance training program (consisting of
sets of 3-5 with 85% of 1RM for several exercises).
2. Impact loading generally led to larger bone adaptations toward the distal ends of
the radius and tibia (i.e. ankles and wrists), while heavy resistance training led to
larger bone adaptations in the femoral neck and the shafts of the radius and tibia.
I
n America, osteoporosis affects
approximately 1 in 4 women and
1 in 8 men over 50 years old. Osteoporosis is a condition characterized
by weakened bones, resulting from low
bone mass and density. Osteopenia –
weakened bones, but not weakened to
the same degree as osteoporosis – is less
dangerous, but even more common, affecting 40%+ of people over 50 years
old. People with osteoporosis or osteopenia are more prone to injuries and are
more likely to become frail as they age.
Bone remodeling can happen at any state
of the lifespan, but it can hum along at
a faster pace when people are young.
Thus, one strategy for osteoporosis prevention is to try to build up your bones
when you’re young, so as bone health
gradually starts declining with age, you
have more of a cushion to work with.
With that in mind, 22 young female
subjects with below-average bone mineral density trained for 10 months, performing either impact loading (punching, jumping, and plyometrics) or
high-intensity resistance training. Both
training protocols improved bone mineral density, mass, and strength, but they
did so in different regions of the bone,
corresponding with the regions where
each type of exercise causes more bone
stress and strain. The impact loading was
most effective at increasing bone health
of the distal radius and tibia, whereas
resistance training was most effective
at increasing bone health in the femoral
neck, along with the shafts of the radius and tibia. Thus, it appears that impact
loading and heavy resistance training
are likely complementary for increasing
bone health.
Purpose and Hypotheses
Purpose
The purpose of this study was to investigate and compare the effects of impact
loading and high-intensity resistance
training on bone outcomes in young
adult women.
7
Table 1
Baseline participant characteristics
Parameter
Impact Training (n=10)
Resistance Training (n=12)
p-value
Age (years)
23.2 ± 3.8
20.5 ± 1.8
0.042*
Height (cm)
165.7 ± 6.5
163.5 ± 6.5
0.427
Weight (kg)
55.6 ± 9.0
56.9 ± 5.5
0.872
BMI (kg/m2)
20.1 ± 2.4
21.0 ± 1.8
0.370
Right forearm length (mm)
263.5 ± 12.8
257.5 ± 13.4
0.300
Left forearm length (mm)
262.2 ± 12.4
257.4 ± 12.7
0.408
Right shank length (mm)
374.4 ± 24.8
368.5 ± 21.7
0.565
Left shank length (mm)
374.6 ± 24.4
369.2 ± 21.7
0.588
Age of menarche (years)
13.7 ± 2.1
12.9 ± 1.4
0.309
tBPAQ
18.6 ± 18.5
18.7 ± 23.0
0.995
Dietary calcium (mg/day)
381.5 ± 235.4
390.3 ± 133.2
0.914
Hormonal contraception
-
-
-
None
5
5
-
OC
5
4
-
Implanon
0
1
-
Merina
0
2
-
Mean ± SD, n=22
BMI = body mass index, tBPAQ = total bone-specific physical activity questionnaire score, OC = oral contraceptive
* = between group difference (p < 0.05)
Hypotheses
No hypotheses were stated.
Subjects and Methods
Subjects
34 subjects were recruited for the
study, but the dropout rate was relatively high, probably due to the length (10
months) of the training intervention.
Thus, 22 subjects completed the study.
To be included, subjects were required
to have below-average (through not
necessarily osteopenic) bone mass in
the lumbar spine and femoral neck, but
to be in good health otherwise. Details
8
Table 2
Adjusted baseline and follow-up indices of distal (4%) radius
Parameter
Impact Training (n=10)
Baseline
Follow-up
Resistance Training (n=12)
% Change
Baseline
Follow-up
% Change
p-value
Dominant
74.94 ± 2.52
78.59 ± 2.85a
4.95 ± 1.88x
80.83 ± 2.28
84.12 ± 2.57a
4.14 ± 1.70x
0.763
Total density (mg/cm3)
301.83 ± 15.63
316.11 ± 12.94
5.26 ± 3.19x
307.35 ± 14.13
310.91 ± 11.70
2.04 ± 2.89
0.484
Total area (mm2)
252.07 ± 13.05
250.90 ± 9.52
0.15 ± 2.75
267.23 ± 11.80
271.69 ± 8.61
2.74 ± 2.48
0.513
Trabecular content (mg)
33.59 ± 2.21
33.57 ± 1.84
0.66 ± 3.98
37.03 ± 1.99
38.17 ± 1.67
4.36 ± 3.60
0.520
Trabecular density (mg/cm3)
188.69 ± 7.17
191.65 ± 7.36
1.80 ± 1.23x
194.17 ± 6.48
196.71 ± 6.65
1.28 ± 1.11x
0.769
Trabecular area (mm2)
180.61 ± 11.82
177.04 ± 8.61
-1.11 ± 3.70
191.68 ± 10.68
194.11 ± 7.78
3.04 ± 3.35
0.439
Total BSI (g2/cm4)
0.23 ± 0.02
0.25 ± 0.02
10.16 ± 4.94x
0.25 ± 0.01
0.02 ± 0.18
6.69 ± 4.47x
0.626
Trabecular BSI (g2/cm4)
0.06 ± 0.01
0.06 ± 0.01
2.17 ± 5.72
0.07 ± 0.01
0.08 ± 0.01
4.68 ± 5.17
0.760
Total content (mg)
Non-Dominant
72.68 ± 2.34b
76.57 ± 2.86ab
5.11 ± 1.50x
82.84 ± 2.12b
84.82 ± 2.58b
2.50 ± 1.35x
0.227
Total density (mg/cm3)
287.15 ± 15.34
310.69 ± 15.07a
8.55 ± 2.26cx
315.10 ± 13.87
319.11 ± 13.63
1.50 ± 2.04c
0.040
Total area (mm2)
257.28 ± 12.65
249.25 ± 12.33
-2.96 ± 3.09x
266.71 ± 11.43
269.54 ± 11.15
1.53 ± 2.79
0.319
34.13 ± 1.72
32.98 ± 1.90
-3.05 ± 4.17
38.46 ± 1.56
38.47 ± 1.72
Trabecular density (mg/cm )‡
194.91 ± 0.00
198.67 ± 1.76
1.86 ± 0.90
Trabecular area (mm )
186.78 ± 11.42
177.56 ± 10.84
b
0.21 ± 0.02
0.24 ± 0.02
a
0.07 ± 0.00
0.07 ± 0.00
Total content (mg)
Trabecular content (mg)
3
2
Total BSI (g /cm )
2
4
Trabecular BSI (g /cm )‡
2
4
ab
0.51 ± 3.77
0.555
b
194.91 ± 0.00
192.36 ± 1.57
-1.30 ± 0.81
0.029
x
-4.53 ± 3.83
191.40 ± 10.33
192.84 ± 9.80
1.42 ± 3.47
0.287
cx
15.35 ± 2.83
b
0.26 ± 0.01
0.27 ± 0.02
2.67 ± 2.55
c
0.005
0.47 ± 5.96
0.07 ± 0.00
0.07 ± 0.00
-0.09 ± 5.31
0.951
cx
cx
Adjusted baseline and follow-up indices of bone strength and percent change (±SE) in pQCT-derived measures of the distal (4%) radius after a 10-month exercise intervention in healthy young adult women with
lower than average bone mass (per protocol data, n=22), p= between-group difference for percentage change univariate ANCOVA (age and values that differed between-groups at baseline were applied as covariates)
a = Within-group based on adjusted mean difference (p < 0.05), b = between-group difference based on adjusted values (p < 0.05), c = between-group differences based on adjusted percent change (p < 0.05)
‡ = baseline value used as covariate in analysis, x = change observed greater than %CV for given variable
about the subjects can be seen in the results tables.
Experimental Design
Subjects were split into two groups.
One group trained with impact loading, while the other group performed
high-intensity resistance training. The
impact loading group performed punches (jabs, crosses, and hooks) to train
their upper bodies, and jumps, hops, and
drop jumps to train their lower bodies.
The resistance training group also performed three upper body (bench press,
overhead press, and bent over rows) and
three lower body (deadlift, squat, and
calf raise) exercises. Subjects in both
groups trained twice per week for 40-45
minutes for 10 months. Punch training
was progressed by the subjects switching from gloves to hand wraps after four
weeks, and simply punching harder over
time (I assume they were punching a
heavy bag; that wasn’t made clear in the
study). Jump training was progressed
by switching from shod (9) to barefoot
jumps after four weeks, increasing the
hurdle height for hops, increasing the
complexity of jumps, and increasing
the height of drop jumps from 15 to
9
Table 3
Adjusted baseline and follow-up indices of the proximal (66%) radius
Parameter
Impact Training (n=10)
Baseline
Follow-up
Resistance Training (n=12)
% Change
Baseline
Follow-up
% Change
p-value
Dominant
Corticol content (mg)
78.38 ± 2.47
78.55 ± 2.63
0.26 ± 1.26
79.38 ± 2.24
80.46 ± 2.38
1.54 ± 1.14
0.483
1127.95 ± 14.34
1127.75 ± 13.26
-0.01 ± 0.60
1107.74 ± 12.97
1116.36 ± 11.99
0.83 ± 0.54x
0.334
Cortical area (mm2)
69.38 ± 1.87
69.57 ± 1.88
0.28 ± 1.18
71.47 ± 1.69
71.90 ± 1.70
0.71 ± 1.07
0.797
Cortical thickness (mm)
2.37 ± 0.11
2.37 ± 0.12
-0.08 ± 1.22
2.35 ± 0.10
2.34 ± 0.11
-0.31 ± 1.10
0.895
Periosteal circumference (mm)
36.86 ± 1.05
36.97 ± 1.03
0.32 ± 1.05
38.27 ± 0.95
38.60 ± 0.93
0.94 ± 0.95x
0.680
Endocortical circumference (mm)
21.96 ± 1.60
22.07 ± 1.67
0.54 ± 1.99
23.51 ± 1.44
23.85 ± 1.51
1.36 ± 1.80
0.775
Polar section modulus (mm2)
253.21 ± 13.37
256.77 ± 12.93
1.35 ± 1.75
269.97 ± 12.09
266.83 ± 11.69
-0.96 ± 1.58
0.363
Weighted polar section modulus
(mm3)
236.14 ± 11.47
237.86 ± 11.67
0.87 ± 2.02
243.45 ± 10.37
244.22 ± 10.55
0.47 ± 1.83
0.892
Corticol density (mg/cm3)
Non-Dominant
78.26 ± 2.80
79.49 ± 2.15
1.75 ± 2.51
80.98 ± 2.53
83.61 ± 1.94a
4.27 ± 2.27x
0.486
1126.96 ± 16.61
1130.98 ± 12.08
0.40 ± 0.84
1101.05 ± 15.02
1130.58 ± 10.92a
2.78 ± 0.76x
0.059
Cortical area (mm2)
69.40 ± 2.00
70.25 ± 1.62
1.36 ± 1.91
73.34 ± 1.81
73.94 ± 1.47
1.35 ± 1.73
0.995
Cortical thickness (mm)
2.39 ± 0.12
2.42 ± 1.11
1.38 ± 1.27
2.41 ± 0.11
2.47 ± 0.10a
2.84 ± 1.15x
0.427
Periosteal circumference (mm)
36.83 ± 1.05
36.96 ± 0.95
0.32 ± 1.04
38.41 ± 0.95
38.07 ± 0.86
-0.72 ± 0.94x
0.491
Endocortical circumference (mm)
21.85 ± 1.62
21.76 ± 1.56
-0.68 ± 1.61
23.25 ± 1.47
22.54 ± 1.41
-2.59 ± 1.46x
0.413
Polar section modulus (mm2)
250.58 ± 15.50
252.19 ± 14.78
0.74 ± 2.59
270.50 ± 14.01
268.12 ± 13.36
-0.15 ± 2.35
0.809
Weighted polar section modulus
(mm3)
231.07 ± 12.60
235.05 ± 12.65
1.73 ± 3.25
237.28 ± 11.39
247.30 ± 11.43a
5.47 ± 2.94x
0.427
Corticol content (mg)
Corticol density (mg/cm3)
Adjusted baseline and follow-up indices of bone strength and percent change (±SE) in pQCT-derived measures of the proximal (66%) radius after a 10-month exercise intervention in healthy young adult women with
lower than average bone mass (per protocol data, n=22), p= between-group difference for percentage change univariate ANCOVA (age and values that differed between-groups at baseline were applied as covariates)
a = Within-group based on adjusted mean difference (p < 0.05), x = change observed greater than %CV for given variable
80cm over time. For resistance training,
weight was added over time in all exercises. For calf raises, subjects performed
5 sets of 10 reps, and for the other exercises, they performed 5 sets of 3-5 reps
with 85% of 1RM, progressing in load
as they were able.
Before and after training, various scans
(DEXA, computed tomography, and
quantitative ultrasound) were performed
to assess bone mass, volume, and density of the tibia, radius, femoral neck, and
calcaneus. Punch velocity was also assessed pre- and post-training in the impact loading group, and bench press and
deadlift strength were assessed every 12
weeks (though potentially not pre-training; the study isn’t entirely clear) in the
resistance training group.
Findings
There were, by my count, 106 different outcomes assessed in this study. You
can see the tables if you want to read
through all of them, but the main takeaways are pretty easy to summarize.
Both modes of exercise were generally effective for promoting increases in
10
Table 4
Adjusted baseline and follow-up femoral neck morphology and percent change (±SE) in DXA-derived 3D hip outcomes
Parameter
Impact Training (n=10)
Baseline
Follow-up
Resistance Training (n=12)
% Change
Baseline
Follow-up
% Change
p-value
Dominant
FN aBMD (g/cm2)
0.857 ± 0.025
0.878 ± 0.019
2.80 ± 1.78
0.847 ± 0.023
0.882 ± 0.017a
4.30 ± 1.61
0.559
FN trabecular BMC (g)
2.83 ± 0.36
2.05 ± 0.10
-10.74 ± 5.86bx
1.84 ± 0.32
2.15 ± 0.09
9.64 ± 5.29bx
0.024
FN cortical BMC (g)‡
1.06 ± 0.00
0.99 ± 0.08
-1.88 ± 5.27
1.06 ± 0.00
0.99 ± 0.07
-1.96 ± 4.72
0.992
FN total BMC (g)
4.06 ± 0.44
3.03 ± 0.14
-11.15 ± 5.77bx
2.76 ± 0.40
3.14 ± 0.13
8.06 ± 5.22bx
0.030
FN trabecular volume (cm3)
10.83 ± 1.37
7.92 ± 0.54
-7.90 ± 6.33x
7.36 ± 1.24
8.67 ± 0.49
9.26 ± 5.73x
0.071
FN cortical volume (cm3)‡
1.72 ± 0.00
1.58 ± 0.12
-3.64 ± 5.96
1.72 ± 0.00
1.66 ± 0.11
-1.91 ± 5.36
0.845
FN total volume (cm3)
12.70 ± 1.46
9.53 ± 0.62
-8.44 ± 6.12x
8.95 ± 1.32
10.30 ± 0.56
7.91 ± 5.53x
0.075
FN trabecular vBMD (g/cm3)
0.26 ± 0.01
0.27 ± 0.01
1.18 ± 4.17
0.25 ± 0.01
0.25 ± 0.01
-0.44 ± 3.77
0.787
FN cortical vBMD (g/cm3)
0.65 ± 0.02
0.61 ± 0.01a
-4.14 ± 2.20bx
0.59 ± 0.02
0.61 ± 0.01
3.68 ± 1.99bx
0.021
FN total vBMD (g/cm3)
0.33 ± 0.01
0.33 ± 0.01
0.40 ± 3.38
0.31 ± 0.01
0.31 ± 0.01
-0.49 ± 3.05
0.855
FN cortical thickness (mm)
1.14 ± 0.05
1.10 ± 0.05
-3.10 ± 5.51
1.08 ± 0.05
1.07 ± 1.05
-1.07 ± 4.98
0.599
Non-Dominant
FN aBMD (g/cm )
0.74 ± 0.026
0.886 ± 0.017
1.89 ± 1.86
0.875 ± 0.024
0.893 ± 0.016
2.23 ± 1.68
0.901
FN trabecular BMC (g)
2.02 ± 0.14
2.01 ± 0.12
-1.46 ± 3.52
1.98 ± 0.12
2.05 ± 0.11
3.92 ± 3.18
0.627
FN cortical BMC (g)
0.85 ± 0.07
0.87 ± 0.07
2.34 ± 6.83
1.00 ± 0.06
1.00 ± 0.06
0.59 ± 6.18
0.859
2.87 ± 0.18
2.88 ± 0.18
0.39 ± 2.55
2.98 ± 0.16
3.05 ± 0.16
2.50 ± 2.31
0.567
FN trabecular volume (cm )
7.72 ± 0.59
7.90 ± 0.61
x
4.55 ± 4.73
8.53 ± 0.53
8.50 ± 0.55
-0.76 ± 4.28
0.439
FN cortical volume (cm3)
1.39 ± 0.12
1.41 ± 0.12
2.19 ± 6.15
1.64 ± 0.11
1.59 ± 0.11
-2.31 ± 5.56
0.612
FN total volume (cm3)
9.11 ± 0.68
9.31 ± 0.71
3.73 ± 4.41x
10.17 ± 0.61
10.08 ± 0.64
-1.04 ± 3.99
0.454
FN trabecular vBMD (g/cm3)
0.27 ± 0.01
0.26 ± 0.01
-1.13 ± 4.27
0.23 ± 0.01
0.24 ± 0.01
4.96 ± 3.87x
0.327
FN cortical vBMD (g/cm3)
0.62 ± 0.02
.062 ± 0.02
0.05 ± 2.38
0.61 ± 0.02
0.63 ± 0.01
3.10 ± 2.15x
0.375
FN total vBMD (g/cm3)
0.32 ± 0.01
0.31 ± 0.01
-1.57 ± 3.33
0.29 ± 0.01
0.31 ± 0.01
3.86 ± 3.01x
0.264
FN cortical thickness (mm)
0.97 ± 0.05
0.95 ± 0.05
-1.05 ± 5.20
1.08 ± 0.05
1.05 ± 0.05
-1.94 ± 4.70
0.905
2
FN total BMC (g)
3
Adjusted baseline and follow-up femoral neck morphology and percent change (±SE) in DXA-derived 3D hip outcomes after a 10-month exercise intervention in healthy young adult women with
lower than average bone mass (per protocol data, n=22), p= between-group difference for percentage change univariate ANCOVA (age and values that differed between-groups at baseline were applied as covariates)
a = Within-group based on adjusted mean difference (p < 0.05), b = between-group difference based on adjusted values (p < 0.05), ‡ = baseline value used as covariate in analysis,
x = change observed greater than %CV for given variable
bone mass and density. However, each
type of exercise had its largest effects at
different regions of the bones. Impact
loading was most effective for promoting bone health toward the distal end of
the radius and tibia (i.e. near the wrist
and ankle), while resistance training
was most effective for promoting bone
health in the shafts of the radius and tibia, and in the femoral neck.
Regarding performance outcomes,
both of the programs seemed to be effective. Punch acceleration increased for
all three punches in the impact training
group, and both bench press and deadlift 1RMs increased in the resistance
training group. As mentioned previously, I think the researchers may not have
assessed 1RMs pre-training (perhaps to
ensure the subjects had sufficient time
11
Table 5
Adjusted baseline and follow-up indices of the distal (4%) tibia
Parameter
Impact Training (n=10)
Baseline
Follow-up
Resistance Training (n=12)
% Change
Baseline
Follow-up
% Change
p-value
Dominant
Total content (mg)
240.10 ± 9.19
247.01 ± 9.35a
3.00 ± 0.85bx
234.95 ± 8.31
234.58 ± 8.45
-0.18 ± 0.77b
0.016
Total density (mg/cm3)
280.67 ± 10.36
286.02 ± 10.98a
1.93 ± 0.83x
280.07 ± 9.37
282.13 ± 9.92
0.72 ± 0.75
0.317
Total area (mm2)
857.19 ± 34.26
863.73 ± 32.69
1.19 ± 1.26
846.93 ± 30.98
840.02 ± 29.55
-0.87 ± 1.14
0.263
Trabecular content (mg)
164.48 ± 7.79
167.44 ± 7.86
2.08 ± 1.44
157.10 ± 7.04
154.15 ± 7.10
-1.88 ± 1.30
0.067
Trabecular density (mg/cm3)
236.21 ± 8.93
238.65 ± 9.39
1.04 ± 0.61x
230.42 ± 8.07
228.71 ± 8.49
-0.75 ± 0.55x
0.052
Trabecular area (mm2)
697.49 ± 29.86
701.78 ± 29.03
1.09 ± 1.38
686.74 ± 27.00
679.50 ± 26.25
-1.14 ± 1.25
0.270
Total BSI (g2/cm4)
0.68 ± 0.04
0.71 ± 0.04a
5.16 ± 1.13bx
0.66 ± 0.04
0.66 ± 0.04
0.37 ± 1.02b
0.008
Trabecular BSI (g2/cm4)
0.39 ± 0.03
0.41 ± 0.03
3.93 ± 1.76bx
0.36 ± 0.03
0.35 ± 0.03
-2.84 ± 1.59bx
0.014
Non-Dominant
243.54 ± 8.71
a
247.51 ± 9.14
1.59 ± 0.75
238.61 ± 7.88
238.48 ± 8.26
-0.09 ± 0.68
0.131
Total density (mg/cm )
289.72 ± 10.92
290.57 ± 11.55
0.32 ± 0.45
278.92 ± 9.87
281.08 ± 10.44
0.71 ± 0.41
0.549
Total area (mm )
844.85 ± 33.91
854.45 ± 35.90
1.29 ± 0.80
864.40 ± 30.66
859.29 ± 32.46
-0.77 ± 0.72
0.084
Trabecular content (mg)
163.68 ± 7.70
167.50 ± 7.97
2.52 ± 1.22
160.73 ± 6.96
157.84 ± 7.20
b
-1.94 ± 1.10
0.018
Trabecular density (mg/cm )
239.76 ± 8.82
242.42 ± 8.91
1.22 ± 0.55
231.05 ± 7.98
229.11 ± 8.06
bx
-0.82 ± 0.50
0.017
Trabecular area (mm2)
685.12 ± 30.27
692.42 ± 31.81
1.28 ± 0.92
701.55 ± 27.37
695.17 ± 28.76
-1.14 ± 0.83
0.079
Total BSI (g2/cm4)
0.71 ± 0.04
0.72 ± 0.04
1.95 ± 0.97
0.67 ± 0.04
0.67 ± 0.04
0.79 ± 0.87
0.408
Trabecular BSI (g2/cm4)
0.40 ± 0.03
0.41 ± 0.03
3.57 ± 1.63b
0.37 ± 0.02
0.36 ± 0.03
-3.15 ± 1.48b
0.009
Total content (mg)
3
2
3
a
bx
bx
Adjusted baseline and follow-up indices of bone strength and percent change (±SE) in pQCT-derived measures of the distal (4%) tibia after a 10-month exercise intervention in healthy young adult women with
lower than average bone mass (per protocol data, n=22), p= between-group difference for percentage change univariate ANCOVA (age and values that differed between-groups at baseline were applied as covariates)
a = Within-group based on adjusted mean difference (p < 0.05), b = between-group difference based on adjusted values (p < 0.05), x = change observed greater than %CV for given variable
to learn the movements before exposing
them to the risks associated with maxing) but between week 12 and the end of
the training program, bench press 1RM
increased from 35.3 ± 5.9kg to 44.3 ±
4.1kg, and deadlift 1RM increased from
66.6 ± 6.3kg to 80.3 ± 7.7kg. It’s worth
noting that the subjects in both groups
only attended about two-thirds of the
training sessions, on average.
Interpretation
Impact loading and resistance training are the two types of exercise most
commonly recommended for improving bone mineral density. Impact loading has a pretty good track record in
the research (2, 3, 4), while resistance
training’s record is a little spottier (5, 6,
7, 8). The authors of the presently reviewed study (1) thought that intensity
was the issue – prior resistance training studies simply didn’t include heavy
enough loading. Bone adaptations are
primarily driven by the amount of stress
placed on specific regions of the bone
(this is known as Wolff’s law). Most of
the bone stress associated with resistance exercise comes from the compressive forces induced by muscle contrac-
12
Table 6
Adjusted baseline and follow-up indices of the tibial shaft (38%)
Parameter
Impact Training (n=10)
Baseline
Follow-up
Resistance Training (n=12)
% Change
Baseline
Follow-up
% Change
p-value
Dominant
Corticol content (mg)
280.80 ± 10.21
283.11 ± 10.43
0.82 ± 0.42x
271.30 ± 9.23
276.30 ± 9.43
1.83 ± 0.38x
0.103
Corticol density (mg/cm3)
1169.66 ± 6.15
1168.48 ± 6.02
-0.09 ± 0.30
1169.78 ± 5.56
1174.37 ± 5.44
0.39 ± 0.27x
0.259
Cortical area (mm2)
240.37 ± 9.20
242.48 ± 9.30
0.93 ± 0.59x
231.94 ± 8.32
235.35 ± 8.41a
1.44 ± 0.53x
0.546
Cortical thickness (mm)
5.04 ± 0.16
5.08 ± 0.15a
0.94 ± 0.41x
4.87 ± 0.14
4.92 ± 0.14a
0.96 ± 0.37x
0.971
Periosteal circumference (mm)
63.40 ± 1.25
63.55 ± 1.28
0.23 ± 0.25x
63.06 ± 1.13
63.43 ± 1.16a
0.59 ± 0.23x
0.313
Endocortical circumference (mm)
31.75 ± 1.26
32.46 ± 1.14
-0.48 ± 0.28
32.46 ± 1.14
32.54 ± 1.18
0.24 ± 0.25
0.084
Polar section modulus (mm2)
1285.41 ± 71.54
1291.81 ± 73.48
-0.60 ± 0.97
1248.27 ± 64.68
1275.23 ± 66.44a
2.08 ± 0.87x
0.293
Weighted polar section modulus
(mm3)
1246.67 ± 66.53
1255.10 ± 69.42
0.69 ± 0.81
1215.98 ± 60.15
1246.33 ± 62.77a
2.43 ± 0.73x
0.146
Non-Dominant
Corticol content (mg)
279.76 ± 10.92
282.76 ± 10.60a
1.15 ± 0.49x
281.89 ± 9.88
281.97 ± 9.88
0.08 ± 0.45
0.141
Corticol density (mg/cm3)
1165.42 ± 5.70
1169.02 ± 6.22
0.31 ± 0.24x
1163.86 ± 5.15
1172.61 ± 5.62a
0.75 ± 0.22x
0.206
Cortical area (mm2)
240.34 ± 9.92
242.16 ± 9.67
0.84 ± 0.66x
242.30 ± 8.97
240.60 ± 8.74
-0.66 ± 0.59x
0.121
Cortical thickness (mm)
5.05 ± 0.16
5.08 ± 0.15
0.68 ± 0.55x
5.02 ± 0.14
4.99 ± 0.13
-0.51 ± 0.50
0.144
Periosteal circumference (mm)
63.27 ± 1.33
63.44 ± 1.32
0.28 ± 0.24x
64.17 ± 1.20
64.01 ± 1.20
-0.25 ± 0.22x
0.137
Endocortical circumference (mm)
31.56 ± 1.24
31.54 ± 1.23
-0.08 ± 0.31
32.66 ± 1.12
32.67 ± 1.12
0.06 ± 0.28
0.753
Polar section modulus (mm2)
1262.29 ± 75.23
1274.45 ± 74.15
1.18 ± 0.99x
1307.26 ± 68.20
1286.63 ± 67.04
-1.50 ± 0.89x
0.070
Weighted polar section modulus
(mm3)
1217.30 ± 69.31
1236.85 ± 71.66
1.70 ± 0.80x
1254.24 ± 62.67
1249.07 ± 64.79
-0.47 ± 0.73
0.072
Adjusted baseline and follow-up indices of bone strength and percent change (±SE) in pQCT-derived measures of the tibial shaft (38%) after a 10-month exercise intervention in healthy young adult women with
lower than average bone mass (per protocol data, n=22), p= between-group difference for percentage change univariate ANCOVA (age and values that differed between-groups at baseline were applied as covariates)
a = Within-group based on adjusted mean difference (p < 0.05), x = change observed greater than %CV for given variable
tion. When loads are heavier, muscles
need to contract harder, thus increasing
the compressive stress on the bones. It
seems that increasing intensity did the
trick, as training with 85% 1RM loads
was able to improve bone health in the
femoral neck and shafts of long bones.
In fact, I suspect that the results of this
study may have undersold the possible
efficacy of resistance exercise for bone
health, at least in the lower body. When
skimming the performance outcomes,
I noticed that the subjects’ bench press
reached a pretty respectable place after
just 10 months of training (the average
bench press exceeded 40kg and 95lbs,
which are big early bench press milestones for female lifters, depending on
whether they use pounds or kilos). Their
deadlifts, on the other hand, a) were not
very impressive and b) failed to show
as much progress as one would expect
from untrained lifters. I’m not trying to
deadlift-shame the subjects; my suspicion is that the researchers were possibly excessively picky about technique
and were too hesitant to increase training
loads. Just to make sure I wasn’t making unjustified assumptions, I checked
13
to see how the subjects’ post-training
bench press and deadlifts 1RMs would
stack up to competitive female powerlifters of a similar age and bodyweight
(57kg Junior division) using Open Powerlifting’s database; their average bench
press would have been in the 14.6th
percentile, while their average deadlift
would have been in the 2.7th percentile.
In other words, their bench press would
be a shade more than one standard deviation below the mean, while their deadlift
would be almost two full standard deviations below the mean. That’s a pretty
huge difference. Thus, I’d expect most
female lifters to experience considerably faster deadlift progress than was
seen in this study, and thus potentially
accrue larger bone adaptations as well.
I’m a little peeved that this study didn’t
include lumbar scans as well. The lumbar spine and the femoral neck are the
two regions most commonly studied in
bone research, since they’re two of the
regions where declining bone health
is the most problematic. My assumption is that resistance training would do
more for lumbar spine density than impact loading (since squats and deadlifts
strongly engage the lumbar spinal erectors), but this study doesn’t provide the
data required to check that assumption.
If you’ve been reading MASS for a
while, you know I have a tendency to
complain about research that’s poorly
done, but I also like to give credit when
it’s due for really impressive research.
BOTH IMPACT LOADING
AND HEAVY RESISTANCE
TRAINING ARE GOOD FOR
BONE HEALTH, AND THEY’RE
LIKELY COMPLEMENTARY
SINCE THEY IMPROVE THE
DENSITY AND STRENGTH OF
DIFFERENT BONE REGIONS.
I don’t know how many people were
working on this study, but it was very
well-done overall. A 10-month training
study is a huge feat by itself, and the
researchers were very thorough in both
the measures they took (for the most
part; that’s what makes the exclusion of
the lumbar spine a bit confusing), and
the thoroughness of their data reporting.
The length of the study was unavoidable, since bone adaptations take place
so slowly – a 12-week training study
may be sufficient for strength or hypertrophy, but would be grossly insufficient
for studying bone mineral density or
content – but it’s impressive to pull it off
nonetheless. These time considerations
explain why there are so many strength
and hypertrophy studies, yet so few
training studies focused on bone health,
14
APPLICATION AND TAKEAWAYS
If you’re interested in training to maximize bone health, a combination of heavy (i.e.
~85% 1RM) resistance training and impact loading is your best bet. Since they primarily
stress different regions of the bone, a combination of both styles of training is likely to
be complementary.
in spite of the fact that osteoporosis is
such a large public health issue.
I think there are a few things to consider before we discuss takeaways. First, we
need to keep the population in mind. The
subjects in this study were untrained and
had below-average bone mineral density to begin with. Can we assume that
the findings would hold true for trained
lifters (does continued training keep improving your bone mineral density?) and
for people with average or above-average bone health? I personally think
we can. I collected data on whole-body
bone mineral density during my thesis
research, and found that among my 21
female subjects, 19 had above-average
bone mineral density for their age, sex,
and ethnicity. The mean bone mineral
density z-score was 1.5, meaning their
bone mineral density was 1.5 standard
deviations better than average (which
corresponds to the 93rd percentile). Of
the two with below-average bone mineral density, one’s BMD z-score was
-0.1, which is average for all intents and
purposes, and the other was the subject
with the lowest bench press and the least
resistance training experience of all sub-
jects. I also found a significant correlation (r = 0.60) between BMD and years
of resistance training experience. So,
while you can’t necessarily draw causal inferences from cross-sectional data,
I do personally think that the results of
this study would be generalizable to other populations. Trained lifters and people with above-average bone health may
not experience bone adaptations at the
same rate as untrained lifters with below-average bone health, but I do think
they keep experienced adaptations that
are qualitatively similar.
With that in mind, I think the takeaways
are pretty clear. Both impact loading and
heavy resistance training are good for
bone health, and they’re likely complementary since they improve the density
and strength of different bone regions. It
may be advisable for female lifters (and
male lifters who’ve been told they have
low bone mineral density, or who may
be at risk for osteopenia or osteoporosis)
to include some punching and plyometrics into their training. For bone adaptations, resistance training needs to be
pretty heavy; we don’t know where the
line is, but 85% 1RM loads seem to do
15
the trick, while 60% 1RM loads don’t.
Maybe 70% is heavy enough and going over 80% isn’t necessary, or maybe
85% is barely enough, and 95% would
be even better; we don’t have the data to
know for sure. I think powerlifters are
probably in the clear, but it may not be a
bad idea for female physique athletes to
purposefully do some heavier sets of 3-5
training for bone health (if that’s a concern), even if reps that low may not necessarily be optimal for muscle growth.
Next Steps
I’d like to see a similar study with a
third condition: one additional group
performing both impact training and
heavy resistance training. I think that
this third group would fare better than
groups doing just impact loading or just
resistance training, but it’s also possible that people have a finite rate of bone
turnover, and that stressing basically all
major bones at multiple different places
would overwhelm the bones’ ability to
adapt.
16
References
1. Lambert C, Beck BR, Harding AT, Watson SL, Weeks BK. Regional changes in indices
of bone strength of upper and lower limbs in response to high-intensity impact loading or
high-intensity resistance training. Bone. 2019 Dec 15;132:115192.
2. Bassey EJ, Ramsdale SJ. Increase in femoral bone density in young women following
high-impact exercise. Osteoporos Int. 1994 Mar;4(2):72-5.
3. Kato T, Terashima T, Yamashita T, Hatanaka Y, Honda A, Umemura Y.Effect of low-repetition jump training on bone mineral density in young women. J Appl Physiol (1985). 2006
Mar;100(3):839-43.
4. Vainionpää A, Korpelainen R, Leppäluoto J, Jämsä T. Effects of high-impact exercise on
bone mineral density: a randomized controlled trial in premenopausal women. Osteoporos
Int. 2005 Feb;16(2):191-7.
5. Gleeson PB, Protas EJ, LeBlanc AD, Schneider VS, Evans HJ. Effects of weight lifting on
bone mineral density in premenopausal women. J Bone Miner Res. 1990 Feb;5(2):153-8.
6. Nickols-Richardson SM, Miller LE, Wootten DF, Ramp WK, Herbert WG. Concentric and
eccentric isokinetic resistance training similarly increases muscular strength, fat-free soft
tissue mass, and specific bone mineral measurements in young women. Osteoporos Int. 2007
Jun;18(6):789-96.
7. Ballard TL, Specker BL, Binkley TL, Vukovich MD. Effect of protein supplementation
during a 6-month strength and conditioning program on areal and volumetric bone parameters. Bone. 2006 Jun;38(6):898-904.
8. Sinaki M, Wahner HW, Bergstralh EJ, Hodgson SF, Offord KP, Squires RW, Swee RG,
Kao PC. Three-year controlled, randomized trial of the effect of dose-specified loading and
strengthening exercises on bone mineral density of spine and femur in nonathletic, physically active women. Bone. 1996 Sep;19(3):233-44.
9. I was asked by the Erics to clarify that “shod” means “wearing shoes.” I think “shod” is a
fun word and am exercising my editorial authority to keep it in the text but am including this
footnote as an olive branch.
█
17
Study Reviewed: High Resistance Training Volume Enhances Muscle
Thickness in Resistance-Trained Men. Brigatto et al. (2019)
Bring the Full Court Press:
Evidence for Really High Volumes
BY MIC HAE L C . ZO URD O S
There is an increasing interest in how many sets per week should be performed
to maximize hypertrophy and strength. This study shows support for 30+
sets; however, there is much more to discuss. Sit back and get ready for a
comprehensive look at set volume needs.
18
KEY POINTS
1. This study had trained men perform various amounts of weekly volume (16 sets,
24 sets, or 32 sets per muscle group) for 8 weeks, then assessed strength and
muscle growth outcomes.
2. Strength and muscle size increased significantly in all three groups. However, almost
all results tended to scale with training volume. Notably, there were remarkably
strong correlations (r = 0.84-0.88) between training volume and muscle growth of
the biceps, triceps, and quadriceps.
3. In brief, this study shows that really high training volumes of 30+ may maximize
both strength and hypertrophy. However, this article considers these results within
a broader context and explores the idea of weekly set volume as a fluctuating
number.
O
n the heels of a relatively recent
study (2) reviewed by Dr. Helms
showing potential benefits for
30+ weekly sets per muscle group to
maximize hypertrophy, there is considerable interest in the necessity of really
high volumes. Although previous meta-analyses show a clear dose-response
relationship between weekly set volume
with both hypertrophy (3) and strength
(4), the vague recommendations of ≥10
sets and ≥5 sets per week, respectively,
do not shed much light on the necessity of high volumes. The ambiguity is
with good reason, as much of the volume research has been conducted mostly on novice trainees, and since volume
needs may increase with training age,
it is difficult to extrapolate exact set
volume targets to everyone. This study
from Brigatto et al (1) had trained men
perform either 16, 24, or 32 sets per
muscle group each week for 8 weeks.
Back squat and bench press one-repetition maximum (1RM) and muscle thickness (muscle size) of the biceps, triceps,
and quadriceps were tested pre- and
post-study. All groups increased both
strength and size, but the 32-set group
had significantly greater increases in
squat 1RM, quadriceps muscle thickness, and triceps muscle thickness than
the 16-set group. Further, effect size
comparisons tended to favor the higher volume groups for all muscle thickness measurements. A simplistic view of
these results supports the notion of a linear dose-response relationship for both
hypertrophy and strength; however, we
need to go much deeper. This study reported the average weekly sets per muscle group that were performed prior to
the study. By gaining further insight into
what the subjects were doing before the
study, we can evaluate if the groups, on
average, increased or decreased their
19
Table 1
Subject characteristics
Subjects
Age (years)
Height (cm)
Body mass (kg)
Training age (years)
Training frequency
(days per week)
27 men
27.2 ± 7.1
176 ± 6
80.6 ± 6.5
3.1 ± 1.1
4.9 ± 0.9
Subject characteristics from Brigatto et al. 2020 (1)
prior training volume to draw more indepth conclusions. Further, we should
understand that an eight-week study that
shows a benefit to very high volume is
really just an overreaching block and is
not necessarily indicative of what set
volume should be all the time, at least
from a practical perspective. This article aims to provide a comprehensive explanation of how to integrate really high
volume training into the broader spectrum of training program theory and design.
Purpose and Hypotheses
Purpose
The purpose of this study was to
compare upper and lower body muscle growth and strength gains between
programs using 16, 24, and 32 sets per
muscle group per week over 8 weeks of
training.
Hypotheses
The authors hypothesized that greater
weekly set volume would lead to greater
muscle growth and strength adaptations
(i.e. 32 set > 24 set >16 set).
Subjects and Methods
Subjects
27 men with an average training age of
about 3 years participated. However, despite a decent training frequency, the average squat and bench 1RMs to start the
study were only 114 ± 26 kg and 98 ±
21 kg, respectively. Further, it was stated that only the top of the thigh needed
to be parallel to the ground on squats;
thus, in terms of powerlifting depth (hip
crease at or below the top of the knee),
squat strength likely would have been
even a little lower. The available subject
details are in Table 1.
Protocol Overview
The training program lasted eight
weeks with pre- and post-testing for
squat and bench press 1RM and for
muscle thickness via amplitude-mode
(A-mode) ultrasound on the biceps, triceps, and vastus lateralis (quadriceps)
occurring the week before and the week
after the training program.
Training Program
Subjects were split into three groups.
Each group performed a different number of sets per muscle group each week:
20
Table 2
Training program
Monday
Tuesday
A Program
B Program
Wednesday
Thursday
Friday
A Program
B Program
G16 (n=9)
Bench press 4 x 8-10 RM
Lat pull-down 4 x 8-10 RM
Cable triceps 4 x 8-10RM
Biceps curl 4 x 8-10 RM
Parallel back squat 4 x 8-10RM
Seated leg curl 8 x 8-10 RM
Rest
Leg extension 4 x 8-10RM
Bench press 4 x 8-10 RM
Lat pull-down 4 x 8-10 RM
Cable triceps 4 x 8-10RM
Biceps curl 4 x 8-10 RM
Parallel back squat 4 x 8-10RM
Seated leg curl 8 x 8-10 RM
Leg extension 4 x 8-10RM
G24 (n=9)
Bench press 6 x 8-10 RM
Lat pull-down 6 x 8-10 RM
Cable triceps 6 x 8-10RM
Biceps curl 6 x 8-10 RM
Parallel back squat 6 x 8-10RM
Seated leg curl 12 x 8-10 RM
Rest
Leg extension 6 x 8-10RM
Bench press 6 x 8-10 RM
Lat pull-down 6 x 8-10 RM
Cable triceps 6 x 8-10RM
Biceps curl 6 x 8-10 RM
Parallel back squat 6 x 8-10RM
Seated leg curl 12 x 8-10 RM
Leg extension 6 x 8-10RM
G32 (n=9)
Bench press 8 x 8-10 RM
Lat pull-down 8 x 8-10 RM
Cable triceps 8 x 8-10RM
Biceps curl 8 x 8-10 RM
Parallel back squat 8 x 8-10RM
Seated leg curl 16 x 8-10 RM
Leg extension 8 x 8-10RM
Rest
Bench press 8 x 8-10 RM
Lat pull-down 8 x 8-10 RM
Cable triceps 8 x 8-10RM
Biceps curl 8 x 8-10 RM
Parallel back squat 8 x 8-10RM
Seated leg curl 16 x 8-10 RM
Leg extension 8 x 8-10RM
From Brigatto et al. (1)
RM = Repetition Maximum
G16, G24, and G32 = 16, 24, and 32 sets per week per muscle group.
1) 16 set, 2) 24 set, and 3) 32 set. Each
group performed four total training sessions per week and two sessions for
each muscle group; thus, each group
had an “A” session that was performed
on Mondays and Thursdays and a “B”
session performed on Tuesdays and Fridays. The details of the training program
can be seen in Table 2.
To hit the appropriate set numbers, the
32-set group performed 16 sets of multijoint exercises and 16 sets of single-joint
exercises. The 24-set group performed
12 sets of both multi- and single-joint
movements, and the 16-set group performed 8 sets of each. The only exception to the above is that the hamstrings
were trained with solely leg curls; thus,
each group got the totality of sets for the
hamstrings with a single-joint movement. Using this strategy, large muscles, such as the chest, received all sets
through “direct” training such as bench
press and dumbbell flyes. Smaller mus-
21
Table 3
Descriptive characteristics and training history prior to study
Variables
G16 (n=9)
G24 (n=9)
G32 (n=9)
RT experience (mo)
51 ± 40
32 ± 7
34 ± 8
RT frequency (sessions/week)
4.8 ± 0.9
5.2 ± 1.1
4.9 ± 0.8
Total number of sets (sets/week)
226 ± 128
171 ± 47
210 ± 50
Number of sets - chest (sets/week)
27 ± 14
20 ± 7
25 ± 7
Number of sets - back (sets/week)
28 ± 14
20 ± 6
25 ± 5
Number of sets - shoulder (sets/week)
45 ± 27
34 ± 11
43 ± 14
Number of sets - biceps (sets/week)
42 ± 27
35 ± 10
41 ± 11
Number of sets - triceps (sets/week)
42 ± 27
34 ± 11
38 ± 9
Number of sets - quadriceps (sets/week)
21 ± 13
16 ± 5
19 ± 7
Number of sets - hamstrings (sets/week)
21 ± 13
12 ± 8
18 ± 7
1RM bench (kg)
93 ± 20
103 ± 23
98 ± 20
1RM squat (kg)
105 ± 20
117 ± 32
121 ± 27
MT of biceps brachii muscle (mm)
38.2 ± 3.9
38.2 ± 4.5
35.6 ± 3.1
MT of triceps brachii muscle (mm)
33.9 ± 4.3
33.6 ± 4.3
35.9 ± 3.8
From Brigatto et al. (1)
There were no differences between groups for any baseline measure
RT = Resistance Training, 1RM = One-Repetition Maximum, MT = Muscle Thickness (assessed via A-mode ultrasound)
G16, G24, and G32 = 16, 24, and 32 sets per week per muscle group
cle groups such as the biceps received
half the sets through direct training
(curls) and half the sets through indirect
stimulation (lat pulldowns).
All sets were performed for an 8-10RM
and were said to be taken to failure, and
the training load was adjusted to keep
subjects within the range. Further, it
was specifically stated that subjects performed each set to the “point of momen-
tary concentric muscular failure” and
that subjects reported a 9.5 or 10RPE
on each set using the repetitions in reserve-based RPE scale. Only one minute was given between sets. I’ll elaborate more later, but for now, just think
about the practicality of performing 32
sets per week for each muscle group, all
to failure.
22
Table 4
Strength findings
Variables
Pre-study
Post-study
Δ%
1RM bench (kg)
G16
93 ± 20
115 ± 21*
23.6
G24
103 ± 23
124 ± 23*
20.9
G32
98 ± 20
126 ± 17*
28.7
1RM squat (kg)
G16
105 ± 20
123 ± 19*
16.6
G24
117 ± 32
138 ± 32*
18.1
G32
121 ± 27
151 ± 25#
25.4
From Brigatto et al. (1)
1RM = One-Repetition Maximum, G16, G24, and G32 = 16, 24, and 32 sets per week per muscle group,
Δ% = Percentage change from pre- to post-study, * = Significant increase from pre- to post-study,
# = G32 Significantly greater gains than G16 in the squat.
Previous Training History
One of the best parts about this study
is that the researchers recorded how
many sets per muscle group per week
subjects were doing prior to the study.
By gathering this information, we can
see if subjects, on average, increased or
decreased their weekly set volume. We
will use this information to help our interpretation later on. For now, you can
view these baseline statistics along with
baseline 1RMs and muscle thickness
values in Table 3.
Findings
Strength
All groups increased 1RM from preto post-study. There were no differences between groups for strength changes
in the bench press; however, the 32-set
group had a significantly greater increase
in squat 1RM compared to the 16-set
group (Table 4). Further, as seen in Table 5, the 32-set group had potentially
meaningful effect sizes comparisons in
its favor for both squat and bench press
1RM versus both the 16-set and 24-set
23
Table 5
Effect size comparisons for strength
Exercise
Comparison
ES (Group favored)
Bench press
16-set vs. 24-set
0.05 (16-set)
Squat
16-set vs. 24-set
0.11 (24-set)
Bench press
16-set vs. 32-set
1.30 (32-set)
Squat
16-set vs. 32-set
0.51 (32-set)
Bench press
24-set vs. 32-set
0.32 (32-set)
Squat
24-set vs. 32-set
0.31 (32-set)
Data Calculated from Brigatto et al. (1)
16, 24, and 32-set = 16, 24, and 32-set per muscle group per week groups
ES = Effect Size. Bolded values meet the criteria of at least a 0.20 ES, which is the cutoff between a
trivial and small ES
groups, suggesting potentially greater
strength gains.
Hypertrophy
Similar to strength, all groups increased hypertrophy at all sites (biceps,
triceps, and vastus lateralis) from pre- to
post-study. The only difference between
groups for muscle growth was a greater
increase in triceps and vastus lateralis
growth in the 32-set versus the 16-set
group (Table 6). However, also similar
to the strength findings, a number of
small to moderate effect sizes favored
both the 24- and 32-set groups (Table 7).
Relationship Between Total Volume
and Outcomes
The significant relationships between
total volume performed and each outcome measure are perhaps the most impressive part of this study’s findings.
Specifically, the authors calculated the
change in total volume (sets × reps ×
weight lifted) from week one to week
eight as accumulated total volume.
Since sets and reps were held constant,
the only variable affecting that equation
was weight lifted. There were significant correlations between total volume
accumulation and every single outcome
measure, and the correlations were
stronger for muscle growth (r = 0.840.88) metrics than for strength (bench: r
= 0.28, squat: r = 0.49) (Figure 1).
24
Table 6
Variables
Pre-study
Post-study
Δ%
Biceps MT (mm)
G16
38.2 ± 3.9
38.4 ± 3.9*
0.5
G24
38.2 ± 4.5
38.7 ± 4.6*
1.3
G32
35.6 ± 3.1
36.7 ± 3.0*
3.1
Triceps MT (mm)
G16
33.9 ± 4.3
34.2 ± 4.3*
0.8
G24
33.6 ± 4.3
35.0 ± 4.7*
4.0
G32
35.9 ± 3.8
38.4 ± 4.2#
7.0
Vastus lateralis MT (mm)
G16
36.2 ± 4.4
36.9 ± 4.0*
2.1
G24
35.4 ± 5.0
37.4 ± 4.6*
5.6
G32
37.1 ± 5.1
40.6 ± 5.1#
9.4
From Brigatto et al. (1)
1RM = One-Repetition Maximum, G16, G24, and G32 = 16, 24, and 32 sets per week per muscle group,
MT = muscle thickness (assessed via A-mode ultrasound), Δ% = Percentage change from pre- to post-study,
* = Significant increase from pre- to post-study, # = G32 Significantly greater gains than G16 in the squat
Interpretation
Despite there being a clear dose-response relationship between volume and
hypertrophy (3), and to a lesser extent
between volume and strength (4), there
are not many studies comparing volumes of >30 sets per week versus lower volumes in trained individuals. Two
of the most applicable studies are from
Heaselgrave et al (5) and Schoenfeld et
al (2) (MASS review by Dr. Helms), so
let’s begin with comparing those findings to the present study from Brigatto
(1). The Heaselgrave study had trained
men perform either 9, 18, or 27 sets of
biceps curls per week. Effect sizes from
Heaselgrave favored the 18-set and 27set groups compared to the 9-set group
for 1RM strength, and the 18-set group
25
Table 7
Effect size comparisons for hypertrophy
Exercise
Comparison
ES (Group favored)
Biceps
16-set vs. 24-set
0.07 (24-set)
Triceps
16-set vs. 24-set
0.26 (24-set)
Vastus lateralis
16-set vs. 24-set
0.28 (24-set)
Biceps
16-set vs. 32-set
0.26 (32-set)
Triceps
16-set vs. 32-set
0.54 (32-set)
Vastus Lateralis
16-set vs. 32-set
0.59 (32-set)
Biceps
24-set vs. 32-set
0.16 (32-set)
Triceps
24-set vs. 32-set
0.27 (32-set)
Vastus Lateralis
24-set vs. 32-set
0.30 (32-set)
Data Calculated from Brigatto et al. (1)
16, 24, and 32-set = 16, 24, and 32-set per muscle group per week groups
ES = Effect Size. Bolded values meet the criteria of at least a 0.20 ES, which is the cutoff between a
trivial and small ES
versus both other groups for biceps muscle thickness. That finding is somewhat
in conflict with the currently reviewed
study, as the highest volume in Heaselgrave (27-set) did not tend to lead to
greater muscle growth. However, when
looking at the individual responses in
the Heaselgrave study, four subjects in
the 9-set group actually saw a reduction
in biceps muscle thickness, which could
have been a product of some individuals actually doing less volume than what
they were accustomed to. Another factor
in the Heaselgrave study is that the 18and 27-set groups performed curls twice
per week, while the 9-set group only
trained once per week; thus, the greater
frequency alone could have contributed to the enhanced strength adaptation.
Results of the Schoenfeld et al study
(2) showed that increases in biceps and
quadriceps muscle thickness tended to
scale with increasing weekly set volumes per muscle group (30-45 > 18-27
26
Figure 1
Relationship between accumulated total volume and outcomes
1.0
r-value
0.7
r-value
0.49
r-value
0.84
r-value
0.86
r-value
0.88
∆mm
MT biceps
∆mm
MT triceps
∆mm
MT vastus
lateralis
r-value
0.28
0.4
0.1
-0.2
∆kg
1RM bench
∆kg
1RM squat
From Brigatto et al. (1)
R-value = Correlation between accumulated total volume (volume in week-8 – volume in week-1) and each outcome measure.
MT = Muscle thickness (assessed via A-mode ultrasound), Δ = change from pre- to post-study, mm = units for MT.
Correlations across all 27 subjects. All correlations were positive and significant.
> 6-9 sets). However, in contrast with
the currently reviewed study, Schoenfeld did not find any differences between
groups for strength gains. In terms of
hypertrophy, these previous results coupled with the present study suggest that
really high volumes (30+ sets per week)
can be beneficial in the short term. One
interesting difference between the present study and the Schoenfeld study is
that Schoenfeld had the low-, moderate-, and high-volume groups perform
one set, three sets, or five sets of each
exercise (bench press, military press,
lat pulldowns, seated rows, squats, leg
press, and leg extension) three times per
27
week. In reality, this is only 15 direct
sets of chest (in the high-volume, 30to 45-set group), but 45 sets of quads
and no direct biceps work (although 30
indirect sets of biceps). However, the
high-volume group experienced greater
biceps and quadriceps growth than the
moderate- and low-volume groups in
Schoenfeld, which is in agreement with
this study that really high volumes can
be beneficial in the short term for hypertrophy.
The preceding paragraph used the
words “short term” several times. Both
the present study and the Schoenfeld
study lasted eight weeks. While this is
an appropriate and common length for
a training study, as it’s difficult to carry
out longer training studies, eight weeks
essentially amounts to one training
block. Raise your hand if about 10 years
ago you ran the Smolov base mesocycle
for your squat and Smolov Jr. for your
bench (my hand is raised). Did it work?
If you had a reasonable training background prior to starting and didn’t set
your 1RMs too high, then the answer is
most likely “yes.” And by “worked,” I
mean on your post-testing day you saw
a large increase in strength from where
you were four weeks earlier, but this
increase likely did not sustain for long.
Also, if you tried to run the program
again right away, it is likely that strength
stagnated or regressed, or you got injured. Those Smolov programs are essentially short-term overreaching cycles
THIS STUDY WAS A SHORTTERM OVERREACHING
PROTOCOL FOR THE
LOWER BODY FOR SOME
INDIVIDUALS IN THE
HIGHER VOLUME GROUPS.
that are a significant increase in frequency and volume compared to what people
typically do. The high-volume groups in
the current study could be viewed similarly, which means that we shouldn’t
necessarily take these findings and say,
“trained people need to do 30+ sets all
the time to maximize progress.” In Table 3, you can see how many sets per
week the subjects reported doing prior
to this study. In the case of the 16-set
group, there was more than a 50% reduction, in some cases, in sets per muscle group. The 24-set and 32-set groups
either saw a more modest reduction in
set volume or an increase. Importantly, the 24- and 32-set groups both saw
an increase in direct sets of the chest
and quadriceps, which were the muscle
groups tested for strength (bench press
and squat). Further, this reporting of
pre-study sets doesn’t classify what exercises were used to achieve these sets.
28
WHEN PERFORMING REALLY
HIGH VOLUME FOR A MUSCLE
GROUP, IT MAKES SENSE TO
TRAIN THAT MUSCLE GROUP
THREE TIMES PER WEEK FOR
THAT BLOCK, AND YOU COULD
STILL TRAIN OTHER MUSCLE
GROUPS TWICE PER WEEK.
The 32-set group reported an average
of 19 sets for quads prior to the study;
however, I doubt all of those sets were
from squats alone. It seems more likely that around 10 of those sets (at most)
were from squats, which would mean a
substantial increase in squat set volume
for the study. When you consider this,
the enhanced strength gains become less
surprising, as much more practice on the
tested lifts was achieved. The muscle
growth differences also make even more
sense between groups, as some subjects
in the high-volume groups may have
seen a large increase in volume accumulated by compound movements, while
some in the 16-set group may have actually performed less volume than they
were previously doing on the compound
movements. So, it is worth considering
that this study was a short-term overreaching protocol for the lower body for
some individuals in the higher volume
groups. Great job by the authors for collecting information related to subjects’
recent training history; hopefully other
researchers continue that trend going
forward.
We should also consider that set volume is not a static entity. I think it’s
unlikely that this is as simple as: your
volume to optimize growth is 32 sets (or
whatever number is individual to you)
per week and then that number periodically increases as training age increases.
I do think that, on average, more highly
trained individuals need more volume,
but think about the logistics of always
performing really high volume. Can you
maintain 32 sets on a muscle group from
now until the end of time? That seems
difficult to do even for one muscle group.
Certainly, it would be difficult to do 32
direct sets for every muscle group every
single week. The authors of the present study cite a study from Radaelli et
al (6) in their discussion that shows that
when training three times per week for
six months, 30 sets per week continued
to provide greater triceps hypertrophy in
the latter part of the study compared to
6 or 18 sets per week. Radaelli had subjects perform one, three, or five sets of
an exercise per session, and five sets of
bench press and five sets of triceps were
performed in each session in the five-set
29
group; thus, the 30 sets of triceps was actually only 15 sets of direct triceps training. Doing 15 direct sets over the long
term seems much more feasible than doing 30 direct sets, especially when those
15 sets are split up over a frequency of
three days per week. The present study
had subjects train at an 8-10RM twice
per week (all sets to an RPE 9.5-10)
with only 60 seconds rest between sets,
and load was adjusted after each set to
stay within the 8-10RM range. That is
a really difficult training program and,
logistically, probably a nightmare to
do forever, especially packing all 30+
sets into two sessions. For now, I think
it might be wise to consider really high
volumes on one or two muscle groups
for a training block, and then reduce the
volume on those muscle groups for the
next block while you increase the volume on others. That strategy might make
training a bit more tolerable. Further, the
present study distributed sets for each
muscle group over only two sessions,
and two previous studies by Barbalho et
al found that 5-10 sets per week tended to lead to greater 10RM strength and
muscle growth in both men (reviewed
by Greg - 7) and women (8) compared
to 15-20 sets when frequency on each
muscle group was only once per week.
The findings from Barbalho suggest that
it is also important to consider session
volume. Therefore, frequency could be
used as a vehicle to increase volume.
When performing really high volume for
a muscle group, it makes sense to train
that muscle group three times per week
for that block, and you could still train
other muscle groups twice per week, if
you wish. By using a higher frequency, you could also lengthen rest times,
since longer rest times could cause total training session time to become too
long when trying to pack really high
volume into only one or two weekly
sessions per muscle group. Further, you
could also sustain a higher load by taking longer rest and potentially perform
similar total volume with fewer sets by
resting more. It is probably a good idea
to avoid failure on the main lifts some of
the time. In short, this study does indeed
show that higher volumes can be effective, but the protocol of really short rest
and only a two time per week frequency
probably set the high volume group up
for the win. If longer rest intervals and
higher frequencies were given to lower
volume training, we can’t assume the results would be the same. I realize there’s
a lot to unpack here, but with each study,
we must keep in mind our broader conceptual understanding to determine how
to actually use the findings.
Since we are talking about session volume and training frequency, way back
in Volume 2 of MASS, Greg covered a
systematic review showing that strength
gains scaled with training frequency (9)
when volume was not equated between
high and low frequencies (when higher
frequencies allow for higher volumes).
In practical terms, as alluded to above,
30
higher frequencies are probably a good
idea to accumulate more volume. In the
context of high weekly volumes, trying
to pack it all into one or two sessions
has various drawbacks: 1) The sessions
are very time consuming; 2) The load
being used will likely have to be lowered considerably for the last few sets,
and the quality of work could be low; 3)
Technique, especially on the main lifts,
could break down with really high session volumes. Thus, a more reasonable
number of sets per session with a higher
frequency has support for better strength
gains and practically may be a good idea
for hypertrophy. Also, as stated above,
by training more frequently, you can
probably get away with training shy of
failure and taking longer rests. This may
allow sessions to be more enjoyable and
could lead to greater adherence in the
long run.
To go along with the “is the set volume number static?” question as we discussed above, we should revisit the idea
that rotating training blocks of higher
volume and lower volume on certain
muscle groups is not just practical, but
may also be a good idea to maximize hypertrophy in the long-term. To be clear,
there is no definitive evidence showing
this, but it is worth exploring. Previously, we discussed in MASS that strength
and hypertrophy losses are very minimal after two weeks of detraining, and
that retraining can even accelerate gains
(10). While that is not exactly looking at
really high volumes followed by periods
of low volumes and then periods of high
volumes again, it is enough to suggest
the possibility that you can desensitize
yourself to volume, which might be to
your advantage over the long run. And
again, this volume cycling (or volume
periodization) may be far more practical
than always performing 30+ sets of volume and looking to increase that number
from time to time. Recently, Dr. Cody
Haun spoke on the topic of cycling volume, which is worth a listen here.
When determining weekly volume targets, it should always be considered that
necessary training volumes are highly
individual and dependent on a variety
of factors. The response in the study
was actually far less variable than I expected to see. Although in Figure 2, you
can still see some degree of variability, which I’ll cover in a moment, these
results scale remarkably well with volume. As both Eric T. and Greg pointed out, one reason for the homogenous
response could be that the authors used
an A-mode ultrasound as opposed to the
more typical B-mode ultrasound. For
muscle thickness measurements, images obtained from B-mode ultrasound
machines are of higher quality and substantially clearer than those obtained
from A-mode ultrasound machines. As
a result, obtaining a thickness value
from a B-mode image is pretty easy and
straightforward, whereas A-mode images place a much greater challenge on the
31
Figure 2
Individual raw value changes in muscle thickness
Pre- to post-MT changes in mm
5
16-set
24-set
4
32-set
3
2
1
0
-1
MT biceps
MT triceps
MT vastus lateralis
From Brigatto et al. (1)
MT = Muscle thickness (assessed via A-mode ultrasound), Gray Shaded Area = To be considered at least the “smallest worthwhile change”
an individual needed to increase MT outside of the gray area, Dots = individual subjects, Horizontal Lines = Mean change for each group
person analyzing the scans and open up
more room for measurement error. To be
fair, an A-mode device is considerably
less expensive, so it is understandable
why the authors may have used this machine.
Now onto Figure 2. In Figure 2, the
dots are individual subjects, the horizontal lines are the mean change for each
group, and the gray shaded area shows
that any change which did not elevate
higher than that box did not meet criteria to be a “worthwhile change.”
While the strong correlations in this
study clearly show that muscle growth
scales with volume, Figure 2 still shows
a degree of individual response variability (again though, the results are not as
individual as I was expecting and scaled
remarkably with volume). For example,
when looking at triceps muscle thickness, you see that the individual with the
32
second highest raw growth response was
in the 24-set group, while four subjects in
the 16-set group improved triceps thickness just as much as one subject in the
24-set group. For vastus lateralis thickness, five subjects in the 16-set group
performed just about as well as five of
the subjects in the 24-set group. Although this study provided mean data related to how many sets per muscle group
subjects did before the study, there was
no analysis of whether muscle growth or
strength gains were related to the individual change in sets performed. So, it’s
possible that those in the 16-set group
who had high quad growth increased set
volume or at least quad-specific volume
compared to pre-study training. We also
know that there is a lot of inter-individual variation in recoverability from a
training session (11). Thus, it is possible
that the two subjects in the 32-set group
who increased vastus lateralis thickness
to a lesser degree than two of the 24-set
subjects recovered at a slower rate between sessions. The recovery aspect is
especially relevant in this study since
all sets were taken to failure. Further,
we know that there are low-, moderate-,
and high-responders to training, which
depends on physiological factors such
as satellite cell and myonuclear number
per myofiber (12). We can’t know exactly what caused the individual response
in this study, but practically, we know
it exists. Ultimately this is to say, if you
currently perform 15 sets per week on a
muscle group and immediately jump to
30+ based on these findings, there is no
guarantee that you will see double your
current progress.
Ramblings and Quick Hits
This was a long one, so thanks if
you’re still with me. I just have some
other quick thoughts as we finish up to
illustrate how we should always view
findings conceptually and place them
within the broader context. Some muscles may require more volume than
others, and this too may be for individual reasons. We have a previous article
which discusses that upper body movements may require less volume than
lower body movements (13), and that is
partially supported by the current study,
as the increase in squat 1RM was significantly greater in the 32-set versus the
16-set group, but the bench press failed
to reach significance for this comparison. Individual volume may also depend
on biomechanics and leverages. For example, if someone has a short torso and
long femurs, a squat might beat up their
lower back a bit more than someone
with the opposite proportions. These
biomechanics might require someone’s
squat frequency and volume to be lower than a lifter who tolerates the squat a
bit better. In that case, volume will need
to be mainly accumulated through other exercises to stimulate hypertrophy,
which may mean more total sets since
more single-joint movements are being
used. The currently reviewed study also
33
APPLICATION AND TAKEAWAYS
1. This study showed that both strength and muscle growth scaled with training
volume, and continued to improve with really high volumes (30+ sets per week).
The relationships between volume and muscle growth were stronger than the
relationships between volume and strength adaptation.
2. Although there is a clear dose-response relationship between volume with both
strength and hypertrophy, and it is clear that really high volumes can be beneficial
at times, we should be cautious about performing really high volumes all the time.
When looking at the pre-study set volumes, it is probable that those in the 32-set
group experienced an increase in volume, and those in the 16-set group experienced
decreased set volume, which helps explain some of the results.
3. It might make sense to cycle high and low volumes, which is essentially volume
periodization. In this way, you could perform higher volume on some muscle groups
while low volume is performed on other muscle groups. This might be a more
sustainable approach instead of just using really high volumes over the long term.
employed what is traditionally referred
to as a non-periodized program (i.e.
no change in set number or reps either
within a week or over time), with basic
progressive overload as needed. Obviously, this strategy yielded significant
progress, but a fairly recent study from
De Sousa et al (14) found both traditional periodization and daily undulating periodization produced faster increases in
quadriceps hypertrophy over the first six
weeks of training compared to non-periodized training despite equivalent volumes (MASS review). Now consider
that the current study used a non-periodized program, a frequency of twice
per week, failure training, and short rest
intervals. It’s possible that a lower volume program which improves on all of
those details could have yielded similar
or even greater adaptations. We can’t
know that for sure, but it’s worth considering. And perhaps more importantly, it’s worth considering that rectifying
all of those factors and cycling high and
low volumes might maximize adaptations over the long term by providing a
more sustainable framework.
Next Steps
The ideal study is longer term (i.e. six
months to a year) and compares a group
performing really high volumes (30+
sets per week) versus moderate (1020) and low (5-10) weekly set volume
groups. While, the aforementioned Barbalho studies did compare different set
volumes over six months, the highest
volume group was 20 weekly sets, and
the per-muscle-group frequency was
34
only once per week. Unfortunately, it is
difficult logistically to carry out these
long-term studies, and we may not see it
anytime soon. I’d also be interested in an
eight-week study that compared cycling
high and low volumes after four weeks
among different muscle groups, versus
a group who performed high volume the
entire eight weeks and a third group that
performed low volume for the entire
eight weeks. In the latter study, I would
be really intrigued by the lifters’ perceptions regarding the sustainability and
likelihood that they could continue the
style of training performed in the study
over the long term.
35
References
1. Brigatto FA, de Medeiros Lima LE, Germano MD, Aoki MS, Braz TV, Lopes CR. High
Resistance-Training Volume Enhances Muscle Thickness in Resistance-Trained Men. The
Journal of Strength & Conditioning Research. 2019 Dec 27.
2. Schoenfeld BJ, Contreras B, Krieger J, Grgic J, Delcastillo K, Belliard R, Alto A. Resistance
training volume enhances muscle hypertrophy but not strength in trained men. Medicine and
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3. Schoenfeld BJ, Ogborn D, Krieger JW. Dose-response relationship between weekly resistance training volume and increases in muscle mass: A systematic review and meta-analysis.
Journal of sports sciences. 2017 Jun 3;35(11):1073-82.
4. Ralston GW, Kilgore L, Wyatt FB, Baker JS. The effect of weekly set volume on strength
gain: a meta-analysis. Sports Medicine. 2017 Dec 1;47(12):2585-601.
5. Heaselgrave SR, Blacker J, Smeuninx B, McKendry J, Breen L. Dose-Response Relationship
of Weekly Resistance-Training Volume and Frequency on Muscular Adaptations in Trained
Men. International journal of sports physiology and performance. 2019 Mar 1;14(3):360-8.
6. Radaelli R, Fleck SJ, Leite T, Leite RD, Pinto RS, Fernandes L, Simão R. Dose-response of
1, 3, and 5 sets of resistance exercise on strength, local muscular endurance, and hypertrophy. The Journal of Strength & Conditioning Research. 2015 May 1;29(5):1349-58.
7. Barbalho M, Coswig VS, Steele J, Fisher JP, Giessing J, Gentil P. Evidence of a ceiling effect
for training volume in muscle hypertrophy and strength in trained men–less is more?. International journal of sports physiology and performance. 2019 Jan 1;1(aop):1-23.
8. Barbalho M, Coswig VS, Steele J, Fisher JP, Paoli A, Gentil P. Evidence for an upper threshold for resistance training volume in trained women. Medicine & Science in Sports & Exercise. 2019 Mar 1;51(3):515-22.
9. Grgic J, Schoenfeld BJ, Davies TB, Lazinica B, Krieger JW, Pedisic Z. Effect of resistance
training frequency on gains in muscular strength: a systematic review and meta-analysis.
Sports Medicine. 2018 May 1;48(5):1207-20.
10. Hwang PS, Andre TL, McKinley-Barnard SK, Marroquín M, Flor E, Gann JJ, Song JJ,
Willoughby DS. Resistance training–induced elevations in muscular strength in trained men
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11. Pareja-Blanco F, Rodríguez-Rosell D, Aagaard P, Sánchez-Medina L, Ribas-Serna J, Mora-Custodio R, Otero-Esquina C, Yáñez-García JM, González-Badillo JJ. Time Course of
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during resistance training in humans is associated with satellite cell-mediated myonuclear
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37
Study Reviewed: A Single Dose of Oral ATP Supplementation Improves Performance
and Physiological Response During Lower Body Resistance Exercise in Recreational
Resistance-Trained Males. de Freitas et al. (2019)
Oral ATP Supplementation
May Enhance Performance,
Albeit Indirectly
BY E RI C HE LMS
Until now, the case for oral ATP as an ergogenic aid was weak. Small
sample studies have either found no positive effects, found benefits
but were methodologically questionable, or found effects that were
inconsistent and small. Most problematic are data suggesting that ATP is
not orally bioavailable. So how did oral ATP enhance performance in this
study? Read on to find out.
38
KEY POINTS
1. Previous data indicated oral ATP supplements were not orally bioavailable,
insomuch as they are broken down into metabolites upon ingestion and fail to
increase blood or plasma ATP levels, even when consumed in a dose 12.5 times
larger than what was used in the present study.
2. Despite this, in the present double-blind, placebo-controlled study, resistancetrained males completed ~20% more repetitions and volume load across four
sets of half-squats at 80% of 1RM when consuming an oral ATP supplement
versus placebo.
3. The likely explanation is that ATP metabolites from the breakdown of the
supplement mediate the effects. However, most metabolites don’t make it through
digestion to the blood intact. Thus, oral ATP may increase endogenous ATP
production before reaching the blood through metabolite absorption in the small
intestine. Endogenously produced extracellular ATP or the final ATP metabolite
uric acid may be increasing blood flow during exercise.
A
denosine triphosphate (ATP)
is the “energy currency” of our
body. It is in every cell, and every physiological function requiring energy – like muscle contraction – gets its
energy from ATP. Thus, it’s no surprise
ATP supplements have been marketed
as supposedly ergogenic substances. In
the present study (1), a 400mg ATP supplement improved the total repetitions
and volume load a group of resistance
trained men could perform while doing
four sets of half-squats to failure with
80% 1RM by ~20% relative to placebo.
Subsequently, this increased their total
energy expenditure as well. However,
previous research (2) found even a 5g
dose of supplemental ATP – 12.5 times
the present study’s dose – was not bioavailable, as it failed to increase blood
levels of ATP. So, how do we explain the
findings in the present study? Read on to
find out.
Purpose and Hypotheses
Purpose
The purpose of this study was to examine the impact of acute ATP supplementation on lower body resistance training
performance and specific hemodynamic
and metabolic physiological responses
in resistance-trained males.
Hypotheses
The authors hypothesized that ATP
supplementation would reduce fatigue
and increase training volume, and subsequently increase oxygen demand.
39
Subjects and Methods
Table 1
Subjects
Age (years)
27.5 ± 5.5
Height (cm)
182.0 ± 0.04
Eleven males (27.5 ± 5.5 years old,
83.4 ± 9.8 kg body mass, and 182 ±
0.04 cm tall) with at least one year of
resistance training experience (3.4 ± 1.5
years) for a minimum of three days per
week and one hour per day participated
in this study. Participants were required
to not have used any dietary supplements for the six months prior to this
study and were instructed to not use any
supplements or performance enhancing
substances during the study. The characteristics of the volunteers are shown
in Table 1.
Protocol Overview
This was a double-blind, randomized,
crossover study. The participants reported
to the lab on three occasions, each a week
apart: first for initial 1RM half-squat and
anthropometric testing, and then on two
subsequent occasions in which either
a single dose of a placebo or 400mg of
ATP were consumed in a randomized,
double-blind fashion 30 minutes prior to
training (Figure 1).
The researchers went to impressive
lengths to ensure control of confounding
variables. Specifically, they conducted
a pilot study to ensure a similar color,
smell, and taste between the placebo and
ATP supplement, which were delivered
as 200ml flavored drinks. Effectiveness
of blinding was confirmed in exit inter-
General characteristics of the sample,
dietary intake and macronutrient distribution
Mass (kg)
Squat 1RM (kg)
83.5 ± 9.8
127.8 ± 19.7
Dietary intake 24h
Diet CHO (g)
211.3 ± 55.8
Diet PRO (g)
149.7 ± 81.1
Diet FAT (g)
54.13 ± 21.7
Total intake (kcal)
1931 ± 562.1
Dietary intake pre-training
Diet CHO (g)
44.21 ± 18.1
Diet PRO (g)
20.69 ± 9.1
Diet FAT (g)
12.54 ± 6.6
Total intake (kcal)
372.4 ± 109.8
CHO = carbohydrate, PRO = protein, FAT = lipids
views with the participants, who could
not distinguish between the treatment
and placebo. Further, trials were conducted at the same time of day, the participants were instructed to avoid caffeine in
the 12 hours prior to each session, and a
24-hour food recall was instituted in the
first session. Participants were instructed
to replicate their day of eating for subsequent testing occasions. Finally, an
adjustable chair was used to ensure the
same squat depth was used for all halfsquat repetitions.
40
Figure 1
1st Visit
· Test of 1RM
Experimental design
1 week
2nd Visit
1 week
3rd Visit
· 400mg of ATP or Placebo
· 400mg of ATP or Placebo
30 minutes
30 minutes
Half-squat exercise
· 4 x 80% 1RM
· 120s rest interval
Half-squat exercise
· 4 x 80% 1RM
· 120s rest interval
Second and third sessions were conducted in a randomized order
In both training sessions after the 1RM
test in session one, participants completed four sets of half-squats at 80% of
1RM until momentary muscular failure
with two minutes rest between sets. Total repetitions and volume load (sets ×
reps × load) were recorded. Heart rate
and blood pressure were measured 30
minutes after placebo or ATP ingestion,
after each set, and then in 10 minute intervals following completion of all four
sets for an hour. Additionally, a metabolic cart was used to measure oxygen
uptake for 10 minutes continuously following training. Finally, blood lactate
was collected from the ear lobe prior to
training, between sets, and 3, 5, 30, and
60 minutes after the completion of the
last set. Using these data and validated
equations, total oxygen consumption,
energy expenditure, and excess post-ex-
ercise oxygen consumption (EPOC or,
colloquially, the calorie “afterburn”
from exercise) were estimated.
Findings
During the ATP treatment, the participants performed 49.4 ± 11.5 total
repetitions, which was significantly (p
= 0.006) more than during the placebo
condition (40.0 ± 11.0) and was considered a large effect size difference (d =
0.83). Subsequently, significantly greater volume loads were performed during
the ATP treatment condition (4,967.4
± 1,497.9 vs. 3,995.7 ± 1,137.8kg; p =
0.005 and d = 0.73). Thus, the ATP supplement caused a ~20% increase in repetitions and total work compared to placebo (Figure 2).
41
Finally, significantly higher oxygen
consumption during exercise, EPOC
measured in caloric expenditure, and
total caloric expenditure were observed
during the ATP condition. The individual participant data and p-values are displayed in Figure 5.
Interpretation
Animals, including humans, use energy from food to synthesize ATP. Like
its name suggests, adenosine triphosphate is adenosine connected to three
phosphate groups. Importantly, these
phosphate bonds are critical to the energy produced from ATP. Specifically,
a phosphate bond is broken in chemical reactions to produce energy, leaving adenosine diphosphate (ADP) and
phosphate groups, which can then be
recycled to once again make more ATP.
A
Total weight lifted (kg)
Lactate also followed a similar pattern
in both conditions, and while no significant interaction was observed, a visual
trend of higher lactate values in the ATP
condition is apparent when viewing Figure 4.
Figure 2
Comparison between placebo and ATP condition on performance
p = 0.005
6000
5000
4000
3000
2000
1000
0
B
Placebo
ATP
25
Placebo
ATP
20
Repetitions
Heart rate and blood pressure before,
during, and after conditions are displayed in Figure 3. Overall, the patterns
were what one would expect and similar
between conditions. The only significant
difference (p < 0.001) between placebo
and ATP was a higher heart rate after the
fourth set for the ATP condition compared to placebo (~10 beats per minute).
15
a
a
10
a,b
a,b
a,b
a,b
5
0
Set 1
Set 2
Set 3
Set 4
ATP = adenosine-5-triphosphate
A = Total weight lifted (kg), B = Maximum number of repetitions in each series
a = Main effect of time with Bonferroni’s test and p value < 0.05 compared to set-1, b = Main effect of
time with Bonferroni’s test and p value < 0.05 compared to set-2
Thus, to provide energy, ATP is constantly recycled in the body. Very little
ATP is actually stored. Rather, this repeating “exchange” process produces
energy, and it is why ATP is considered
our central energy “currency,” and why
it’s a focus for nutritional supplementation. While the present findings of more
reps and greater volume load performed
(and subsequently a greater energy ex-
42
Comparison between placebo and ATP condition
on heart rate and blood pressure
A
200
Placebo
190
ATP
180
170
160
HR (bpm)
150
140
130
120
110
100
90
80
70
60
50
Rest Post ATP set-1
B
set-2
set-3
set-4
10'
20'
30'
40'
50'
60'
180
Placebo
ATP
170
160
SBP (mm/Hg)
The first human trial of ATP supplementation was a placebo-controlled
study conducted by Jordan and colleagues (3). Performance outcomes
were observed after acute supplementation and after 14 days of supplementation with 150 or 225mg of an ATP supplement in 27 healthy males. Wingate
testing, machine chest press 1RM, and
three sets of chest press at 70% of 1RM
to failure were assessed. After acute
and chronic supplementation, no significant changes in blood or plasma ATP
were observed in either group. Further,
Wingate performance was unaffected,
and no significant between-group effects were observed for any muscular
strength parameter. However, Jordan
did observe a small, acute within-group
increase in 1RM (6.6%; p < 0.04) in the
225mg group, which just barely crossed
the line of significance. However, they
noted that this could have been due to
two outlier performances in this group,
or due to the Universal bench press machine which could only be increased or
decreased in ~7kg increments, masking
the true treatment effect or lack thereof. The only potentially noteworthy
findings were that within-group repetitions to failure in set one (18.5%; p <
0.007) and total volume load (22%; p
< 0.003) significantly increased only in
Figure 3
150
140
130
120
110
100
90
Rest Post ATP set-1
C
set-2
set-3
set-4
10'
20'
30'
40'
50'
60'
100
Placebo
95
ATP
90
DBP (mm/Hg)
penditure) in the treatment condition
seem straightforward given the role of
ATP, they are actually unexpected given
the history of ATP supplement research.
85
80
75
70
65
60
55
50
Rest Post ATP set-1
set-2
set-3
set-4
10'
20'
30'
40'
50'
60'
A = Heart rate during and after resistance exercise, B = Systolic blood pressure during and after resistance exercise, C = Diastolic blood
pressure during and after resistance exercise
ATP = adenosine-5'-triphosphate; HR = heart rate (b·min-1); SBP = systolic blood pressure (mm Hg); DBP = diastolic
43
Lactate (mmol\L)
Figure 4
Comparison between placebo and ATP condition on the lactate concentration
13
Placebo
12
ATP
11
10
9
8
7
6
5
4
3
2
1
Rest
Post ATP
set-1
set-2
the 225mg group at the 14-day mark.
Importantly, Jordan and colleagues anticipated that oral delivery of intact ATP
would be problematic due to its high
molecular weight, and the acidic environment of the gut which would partially break down ATP. Thus, they used cellulose “enteric” coated capsules (enteric
means “of or related to the intestine”),
which are designed to pass through the
stomach and be absorbed in the intestine, with the hope that this would result
in greater intact ATP absorption. Given the lackluster findings and failure to
increase blood ATP levels, Jordan and
colleagues couched their findings as potentially spurious. Subsequent follow
up studies seemed to put the perceived
“nails in the coffin” of supplemental
ATP for a few different reasons.
In 2008, Herda and colleagues retest-
set-3
set-4
P3
P5
P30
P60
ed oral ATP based on the limited positive effects observed by Jordan et al, but
they failed to replicate any significant or
potentially meaningful ergogenic effects
(4). This outcome added to the perception that Jordan and colleagues’ findings
were indeed due to random variability.
An important note to remember for later
in this interpretation is that they tested
jump height, maximum voluntary contraction strength, and a single set to failure on bicep curls and leg extensions,
but not performance over multiple sets.
The next “nail” came in the form of a
2012 study by Arts and colleagues (2),
in which the researchers administered a
very large 5g dose of ATP via three distinct delivery methods: 1) enteric coated
oral tablets designed to be digested in
the upper part of the small intestine, 2)
enteric tablets designed for digestion in
the lower small intestine, or 3) through
44
Figure 5 Differences on the oxygen uptake during exercise, excess post-EPOC and total oxygen
consumption in placebo and ATP condition
B
Placebo
ATP
200
20
190
180
170
160
p = 0.021
150
140
130
120
110
100
Exercise oxygen
consumption (lieter)
Exercise oxygen
consumption (ml·kg·min)
A
15
p = 0.010
10
5
90
0
Placebo
ATP
Placebo
C
D
70
100
ATP
60
55
p = 0.667
50
45
40
35
EPOC (kcal)
EPOC (ml·kg·min)
65
30
80
p = 0.041
60
40
25
20
20
ATP
Placebo
E
F
300
200
280
260
240
220
p = 0.062
200
180
160
140
120
100
Total Kilocalorie (Kcal)
Oxygen Uptake (ml·kg·min)
Placebo
ATP
180
160
p = 0.041
140
120
100
80
60
40
Placebo
ATP
Placebo
ATP
A = Oxygen consumption during exercise (ml·kg·min), B = Oxygen consumption during exercise (Liter), C = Excess post-exercise oxygen consumption (ml·kg·min),
D = Excess post-exercise oxygen consumption (Kcal), E = Oxygen uptake (ml·kg·min), F = Total kilocalories (Kcal)
ATP = adenosine-5´-triphosphate, EPOC = excess postexercise oxygen consumption
a tube inserted through the nose, directly into the small intestine (sign me up!).
Neither the very large dose, the enteric coating, the delivery method (oral or
nasal), or their combination, was sufficient to increase blood levels of ATP, or
its metabolites ADP, AMP, adenosine,
adenine, inosine, or hypoxanthine. Only
uric acid, the end-stage metabolite of
ATP, was significantly increased.
Adding to the growing and understandable skepticism of oral ATP as a viable supplement, Wilson and colleagues
published a now infamous series of industry-funded studies comparing HMB
free acid, ATP, and their combination
45
against a placebo (5, 6), reporting outcomes more impressive than some studies on anabolic steroids. This resulted in
three separate letters to journal editors
questioning the plausibility and legitimacy of their findings (7, 8, 9). Much
like I pointed out in my MASS article
on HMB free acid, it’s an understandable reaction to dismiss a supplement if
it was the subject of a shady study, but
it doesn’t necessarily mean the supplement itself is bunk.
Fast forward to today, and the overall
picture looked bleak. It seemed nothing
short of intravenous infusion would increase blood levels of ATP, and the only
clearly positive findings were reported
in studies considered controversial, to
say the least. So how do we explain the
findings of the present study, and why
should we consider them “real”? The
proposed answers to these questions are
found in the discussion of the first study
by Jordan (3), where the authors offered
some plausible explanations of how endogenously produced extracellular ATP
or its metabolites might improve specific types of performance through a few
mechanisms. Oral ATP is unavoidably
broken down in the gut, thus any ergogenic effect stems from its metabolites.
The metabolites of ATP provide the substrates to increase endogenous, extracellular ATP levels. Meaning, even though
ATP doesn’t make it through your digestive tract in one piece, its metabolites
are absorbed in the intestine and used
ORAL ATP IS UNAVOIDABLY
BROKEN DOWN IN THE
GUT, THUS ANY ERGOGENIC
EFFECT STEMS FROM
ITS METABOLITES.
to produce more extracellular ATP. You
may wonder, what’s the value of extracellular ATP if the whole point is to get
ATP into muscle cells for energy? That’s
a fantastic question.
While ATP was initially chosen as a
supplement for its role within cells as
energy currency, it also has “indirect”
effects when sensed by extracellular
receptors. Specifically, ATP and its metabolites, including adenosine, bind to
receptors in blood vessels and muscle
– purinergic receptors P2Y and P2X for
the nerdy – increasing blood flow and
increasing calcium uptake in muscle
(3). Further, ATP and its metabolites can
also act as neurotransmitters which, in
some cases, can increase adrenaline output and alter the pain experience; subsequently, oral ATP is approved as a pain
medication in some countries (3, 10).
To summarize, oral ATP may not make
it into your muscle cells to provide the
originally intended energy boost, but its
46
WHICHEVER SINGLE
METABOLITE OR
COMBINATION OF
METABOLITES IS AT PLAY,
THE RESULT IS POSSIBLY
INCREASED BLOOD FLOW,
SUBSEQUENTLY ENHANCING
BETWEEN-SET RECOVERY.
metabolites that are absorbed are theorized to possibly act directly on receptors to either increase blood flow, contractile efficiency, adrenaline, reduce
pain, or perhaps to enhance your body’s
production of extracellular ATP, which
may result in similar outcomes. So, we
have established that there are a number
of plausible ergogenic mechanisms …
but then why isn’t the data more robust?
Another great question; you’re killing it
today!
This is where I want to go back to that
seed I planted in the fourth paragraph
in italics. In both the original study by
Jordan (3) and in the present study (1),
a within-group increase in volume load
of ~20% was observed in the multi-set
testing protocol in the ATP condition.
In the study by Herda and colleagues
that observed no effect of ATP supplementation, no multi-set testing was performed. To further illustrate this pattern,
Rathmacher and colleagues (10) assessed strength and fatigue in a placebo-controlled crossover trial in men and
women. While strength was unaffected
by ATP supplementation, force output
was better maintained in the second set
of three 50-rep maximal leg extension
sets on a dynamometer (p < 0.01), and
in the third set, force output tended to
decrease less after ATP supplementation
(p < 0.10).
In aggregate, assessing the outcomes
in the reliable extant research, a pattern
in which ATP supplementation does not
improve strength, single-set muscular
endurance, or anaerobic power – but
does improve repeated sets with relatively short rest periods (90-120 seconds) – emerges. Given the proposed
mechanisms by which oral ATP could
“indirectly” enhance performance, I
think the most plausible is an increase
in blood flow. In last month’s article in
which Greg discussed sex differences in
fatigability (here), you may recall that
the principal mechanism for why women recover more effectively set-to-set
is greater blood flow (and thus, oxygen
delivery). This squares with the pattern
in the ATP research. However, the exact mechanism of action, which specific metabolite or metabolites of ATP are
47
responsible, and whether they are exerting this effect directly, or being used indirectly to increase endogenous ATP is
unknown. We can rule out a number of
possibilities, however. For example, the
potential effects of some of ATP’s metabolites are not all necessarily ergogenic. One of these metabolites is adenosine; you may recall that caffeine is an
adenosine receptor antagonist and exerts
some of its ergogenic effects by blocking
adenosine receptors in the brain. While
adenosine acts on receptors throughout
the body, it specifically acts to induce
relaxation in the brain; by blocking adenosine, caffeine can reduce tiredness
and perceived effort. Thus, adenosine
could potentially act like an “anti-caffeine.” Given there weren’t ergolytic
effects observed, and considering adenosine has an incredibly short half life
of ~10 seconds, we can probably rule
it out as a direct actor (11). The other
proposed pathways to performance enhancement theorized by the authors of
the studies where performance was enhanced included: reducing pain, increasing calcium uptake, and/or increasing
adrenaline. However, I personally don’t
think these were in play, or you’d observe more repetitions in a single set to
failure, increased 1RM, force, or power, or improved Wingate performance.
However, all of those metrics remained
unchanged when studied.
A key piece to the puzzle of what is
going on and how it’s occurring is some-
thing I mentioned earlier: It wasn’t just
ATP that failed to increase in the study
by Arts and colleagues (2), but every
ATP metabolite except for uric acid. This
is especially confusing, since almost every proposed ergogenic mechanism that
the present study authors (1), Jordan
and colleagues (3), and Rathmacher and
colleagues (10) mentioned were related
to the metabolites of ATP “upstream”
of uric acid. One explanation for the
outcome in Jordan and Rathmacher, at
least, is that ATP is broken down and adenosine and inorganic phosphate are absorbed by the small intestine, which are
then used to increase liver ATP pools,
which then increase blood and plasma
ATP, impacting performance. Jordan
and Rathmacher observed performance
increases after a couple weeks; however, this process takes time and doesn’t
explain how performance was increased
in the present study just 30 minutes after
ATP ingestion. As Arts and colleagues
(2) noted, blood and plasma ATP were
unchanged acutely. However, it’s possible that uric acid, the only metabolite
which did increase, could maybe impact
blood flow during exercise. There are experimental data (12) showing that very
low levels of uric acid can impair the
vasodilation response to heat (which occurs during exercise) and reduce systolic blood pressure. It’s also possible that
signaling that acutely increases blood
flow occurs during or closely following
ATP metabolite absorption in the intestine, but before endogenous ATP levels
48
APPLICATION AND TAKEAWAYS
ATP supplementation may indirectly increase work capacity during repeated, highintensity fatiguing contractions, such as performing multiple sets to failure or multiple
sets with incomplete rest. This is not due to the delivery of intact supplemental
ATP to muscle. Rather, ATP metabolites from the supplement’s breakdown may
act to increase blood flow and/or stimulate endogenous ATP production to do
the same. This is the first convincing study reporting ergogenic effects, and the
exact mechanism is yet to be confirmed. I recommend waiting until research on
long-term outcomes, ideal dosing, and potential drawbacks is published before
supplementing with ATP.
in blood and plasma increase. In the
end, we don’t know; ultimately, whichever single metabolite or combination of
metabolites is at play, the result is possibly increased blood flow, subsequently
enhancing between-set recovery.
Next Steps
While I’m unsure of the exact mechanism of action, it seems only a specific
type of performance is enhanced when
oral ATP is consumed: more work across
repeated sets, plausibly mediated by enhanced blood flow. However, no one
has yet directly measured blood flow to
muscle at the microvascular level after
oral supplementation of ATP. I think the
next step is to take a step backward; instead of conducting more acute or chronic studies on performance, we need a
dose-response study designed to figure
out which metabolites are at play and
to what magnitude. We also need to ascertain whether or not endogenous ATP
production can be increased, and to what
magnitude over what time course, and to
measure the degree to which blood flow
is enhanced, particularly in the microvasculature. If it’s a specific metabolite
responsible, perhaps it would be better
to supplement with the specific metabolite directly. This study could also determine optimal dosage and any potential
negative effects (like relaxation or sedation if its adenosine, or gout, if it’s uric
acid), which could perhaps manifest at
higher dosages if certain metabolites of
ATP were increased too much.
49
References
1. Freitas MC, Cholewa JM, Gerosa-Neto J, Gonçalves DC, Caperuto EC, Lira FS, Rossi FE.
A Single Dose of Oral ATP Supplementation Improves Performance and Physiological Response During Lower Body Resistance Exercise in Recreational Resistance-Trained Males.
The Journal of Strength & Conditioning Research. 2019 Dec 1;33(12):3345-52.
2. Arts IC, Coolen EJ, Bours MJ, Huyghebaert N, Stuart MA, Bast A, Dagnelie PC. Adenosine
5’-triphosphate (ATP) supplements are not orally bioavailable: a randomized, placebo-controlled cross-over trial in healthy humans. Journal of the International Society of Sports
Nutrition. 2012 Dec;9(1):16.
3. Jordan AN, Jurca RA, Abraham EH, Salikhova AN, Mann JK, Morss GM, Church TS, Lucia A, Earnest CP. Effects of oral ATP supplementation on anaerobic power and muscular
strength. Medicine & Science in Sports & Exercise. 2004 Jun 1;36(6):983-90.
4. Herda TJ, Ryan ED, Stout JR, Cramer JT. Effects of a supplement designed to increase ATP
levels on muscle strength, power output, and endurance. Journal of the International Society
of Sports Nutrition. 2008 Dec;5(1):3.
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6. Lowery RP, Joy JM, Rathmacher JA, Baier SM, Fuller JC, Shelley MC, Jäger R, Purpura
M, Wilson S, Wilson JM. Interaction of beta-hydroxy-beta-methylbutyrate free acid and adenosine triphosphate on muscle mass, strength, and power in resistance trained individuals.
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Henselmans M, Loenneke JP, Norton LE, Ormsbee MJ. Changes in Body Composition and
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11. Sachdeva S, Gupta M. Adenosine and its receptors as therapeutic targets: An overview. Saudi Pharmaceutical Journal. 2013 Jul 1;21(3):245-53.
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█
51
Study Reviewed: Effects of Vitamin D3 Supplementation on Serum 25(OH)
D Concentration and Strength in Athletes: A Systematic Review and Metaanalysis of Randomized Controlled Trials. Han et al. (2019)
Shedding Some Light on
Vitamin D Supplementation:
Does It Increase Strength In
Athletes?
BY E RI C T RE X LE R
Vitamin D deficiency is shockingly common in athletes, and low levels are
associated with reduced strength. A recent meta-analysis suggested that
vitamin D supplementation failed to enhance strength in athletes, but
there’s more to this paper than meets the eye. Read on to figure out if
vitamin D supplementation might be worth considering.
52
KEY POINTS
1. While much of the vitamin D literature focuses on the general population, the
current meta-analysis (1) sought to determine if vitamin D supplementation
enhances strength performance in athletes
2. In order to make the results a bit more intuitive and interpretable, I re-crunched
the numbers. Overall, there was a small effect of vitamin D supplements (d =
0.20, p = 0.34). If you divide up the results by performance outcome, the effect
size for bench press was -0.12 (p = 0.54), and the effect size for isokinetic leg
extension was 0.63 (p = 0.01).
3. The largest effects of vitamin D supplementation were observed in the samples
who started out with the lowest blood vitamin D levels. While there appears to be
a discrepancy between upper body and lower body outcomes, this might be due
to the methods used to measure each strength outcome.
I
t probably shouldn’t be too controversial to suggest that, in general,
vitamin deficiencies aren’t a positive
thing. However, vitamin D has a special
status in the eyes of most lifters, as researchers have previously suggested that
vitamin D supplementation could potentially enhance aerobic performance,
strength performance, muscle growth,
and recovery from exercise (2). Unfortunately, there’s also a bit of uncertainty associated with the management of
blood vitamin D levels; there’s an active
debate about whether the optimal range
is above 50 nmol/L or 75 nmol/L, blood
levels are meaningfully influenced by
latitude and magnitude of sun exposure
(which is difficult to practically quantify), and excessively high blood levels are also problematic. Dr. Helms has
previously discussed vitamin D supplementation in two previous MASS arti-
cles, but this month, there’s a new vitamin D meta-analysis (1) to report and
interpret. Authors of the current paper
(1) specifically evaluated the effects of
vitamin D supplementation on strength
outcomes in athletes. Results indicated
that supplementation significantly increased blood vitamin D levels, but effects on bench press strength (effect size
[d] = -0.07, p = 0.72) and isokinetic leg
extension strength (d = 2.14, p = 0.12)
were not statistically significant, nor
was the overall effect on both strength
outcomes pooled together (d = 0.75, p
= 0.17). Having said that, I think these
numbers should be taken with a grain of
salt. This article explains why I feel that
way and discusses whether or not vitamin D is an advisable supplementation
strategy.
53
Purpose and Hypotheses
Purpose
The purpose of this meta-analysis was
“to investigate the effects of vitamin
D3 supplementation on skeletal muscle
strength in athletes.” As an additional
outcome, they also analyzed the effects
of vitamin D3 supplementation on serum vitamin D levels.
Hypotheses
The authors hypothesized that the meta-analysis would find that vitamin D3
supplementation significantly increases
serum vitamin D levels and significantly
improves strength performance.
Subjects and Methods
Subjects
As a meta-analysis, this paper pooled
the results of multiple studies. A defining
characteristic of this meta-analysis was
that it only included studies that recruited athletes. The sports represented included taekwondo, soccer, judo, rugby,
and football. Strength data were available for a total of 80 athletes, with bench
press data for 49 athletes and isokinetic
leg extension data for 31 athletes.
Methods
The whole point of a meta-analysis is
to search the literature systematically,
then mathematically pool the results together to summarize the collective findings. The authors searched the common
research databases and only included
randomized controlled trials that specifically evaluated strength outcomes
in athletes taking oral vitamin D3 supplements. They excluded any potential
studies that involved non-athletes, vitamin D2 supplementation, interventions
utilizing multivitamins, and studies that
included athletes with illnesses or medical conditions that could have potentially altered outcomes of interest.
With meta-analyses, you are working
toward calculating a pooled effect size.
In order to do that, an effect size (Cohen’s d, or some similar form of standardized mean difference) is calculated
for each study included. Typically, for
this type of literature, you’d calculate
the effect size based on the change in
the placebo group (from pre-testing to
post-testing), the change in the vitamin
D group, and then some form of standard deviation for each group– either
the standard deviation of the pre-test or
post-test value, or the standard deviation
of the change from pre- to post-testing.
For the current meta-analysis, they
took a very different approach. Effect
sizes were calculated using only the pretest value in the vitamin D group, the
post-test value in the vitamin D group,
and the standard deviations at each time
point. This is quite atypical, and totally
ignores a key, defining feature of these
54
Table 1
Baseline and follow-up serum 25(OH)D concentrations
Reference
Jung 2018
Fairbairn 2018
Close 2013b
Latitude
Time
33.3° N
Jan-Feb
45-46.5° S
Mar-May
53° N
Nov-Jan
Vitamin D3 daily dosage
IU
5000
53° N
Jan-Apr
52.3° N
Feb
20
1 week (ng/mL)
4 weeks (ng/mL)
38.4 ± 1.5
13.1 ± 1.0
6 weeks (ng/mL)
8 weeks (ng/mL)
0
12.4 ± 0.8
15
37.2 ± 7.6
28
44.4 ± 7.2
0
38 ± 6.8
29
34 ± 6.8
5000
11.6 ± 10.0
5
41.3 ± 10.0
21.2 ± 11.6
5
29.6 ± 9.6
0
2857
0
Wyon 2016
N=149
10.9 ± 0.5
3570
5714
Close 2013a
Baseline (ng/mL)
20.4 ± 10.4
21.2 ± 10.4
20.8 ± 10.8
12 weeks (ng/mL)
45.6 ± 7.6
32 ± 8.4
6
39.3 ± 5.6
36.5 ± 9.6
10
31.7 ± 5.6
34.1 ± 4.0
9
14.8 ± 7.2
16.4 ± 8.8
18750
13.2 ± 3.8
11
16.8 ± 3.2
0
16.3 ± 2.7
11
16.3 ± 2.6
Data Calculated from Han Q, Li X, Tan Q, Shao J, and Yi M. 2019 (1)
Data are mean ± SD unless stated otherwise
Measurements are in ng/mL
studies, which is that they included a
placebo group. The strength of the placebo-controlled design is that we can
directly evaluate the effect of the treatment above and beyond the effect of the
placebo; to ignore this in the effect size
calculation is to adopt a less informative
interpretation of each study’s individual results. Off the top of my head, I can
only specifically recall seeing one other
recent meta-analysis use this approach
(3), and it was subsequently retracted,
accompanied by a message stating that,
“The authors have retracted this article
because after publication it was brought
to their attention that the statistical approach is not appropriate.” I believe
they’re referring to the manner in which
the effect sizes were calculated, but unfortunately no details were provided.
Findings
As one would expect, oral vitamin D
supplementation significantly increased
blood vitamin D levels; the effect size
was d = 3.0 for all studies together, and
d = 1.18 after removing one study with
a fairly high dropout rate. I have used
informal language up to this point, so
I should clarify that “blood vitamin D
levels” refers more specifically to serum levels of 25-hydroxyvitamin D, or
25(OH)D. The liver converts vitamin
D3 into 25(OH)D, which is then converted to 1,25-hydroxyvitamin D. While
1,25-hydroxyvitamin D is technically
the active form of vitamin D, researchers typically measure 25(OH)D because
it has a longer half-life in the blood, and
its circulating levels are about 1,000
times higher (4). Table 1 shows the
baseline and post-test values for blood
vitamin D levels, along with some key
study characteristics related to vitamin
D levels, such as latitude and time of
year. To assist with interpretation, keep
in mind that 1 ng/mL is equivalent to 2.5
nmol/L, and some scientists suggest that
the ideal blood vitamin D range is 20-40
ng/mL (50-100 nmol/L), whereas others
suggest that it’s 30-50 ng/mL (75-125
nmol/L).
For strength outcomes, the authors
found that supplementation did not significantly alter performance, with an
55
Table 2
Strength outcome measures
Reference
Vitamin D daily dosage
IU
N = 149
1RM BP (kg)
Pre
Jung 2018
Fairbairn 2018
Close 2013b
Close 2013a
Wyon 2016
Post
Leg extension (N·m)
Change
Pre
Post
Change
5000
20
323.6 ± 32.6
350.4 ± 33.5
26.8
0
15
329.9 ± 32.5
339.2 ± 33.7
9.3
3570
28
126 ± 17
122 ± 15
0
29
122 ± 17
123 ± 16
1
5000
5
82 ± 14
88.5 ± 14
6.5
-4
0
5
82 ± 14
84.5 ± 14
2.5
5714
6
91 ± 22
90 ± 20
-1
2857
10
90 ± 13
92 ± 15
2
0
9
79 ± 17
79 ± 18
0
18750
11
232 ± 37.4
265 ± 45.6
33
0
11
239 ± 65.9
239 ± 63.7
0
Data Calculated from Han Q, Li X, Tan Q, Shao J, and Yi M. 2019 (1). Note: We corrected some values from the original text.
overall effect size of d = 0.75. When they
looked at each performance outcome
(bench press or isokinetic leg extension)
in isolation, the bench press effect size
was -0.07, and the leg extension effect
size was 2.14 (but still not statistically significant, with a p-value of 0.12).
The results from each individual study,
along with the vitamin D dosages used,
are presented in Table 2.
If you read my previous review of a
fairly recent creatine meta-analysis,
you know that I tend to be really picky
about how meta-analyses are done.
At first glance, it might seem like I’m
splitting hairs and making a huge deal
out of minor differences. However, the
current meta-analysis presents us with
an awesome example of why meta-analytic methods matter, big time. There
was another vitamin D meta-analysis by
Tomlinson et al in 2015 (5), which included some of the same data. Both included a 2013 study by Close et al (6),
which evaluated two different vitamin D
doses, looking at bench press as an out-
come variable. For the same exact data,
Tomlinson et al calculated an effect size
of d = 0.75 for the low-dose treatment,
whereas the current meta-analysis calculated an effect size of d = 0.14. To
contextualize that gap of around 0.6,
it’s worth noting that caffeine typically
improves strength and power outcomes
with an effect size of around 0.2-0.3 (7),
and a 2003 meta-analysis found that the
effect of creatine on 1RM outcomes was
around 0.32 (8). Furthermore, the current study computed an effect size of
3.55 for Jung et al (9), while the true
value should be less than 1 if you use
virtually any commonly accepted method of effect size calculation. So, while I
admittedly enjoy exploring these details
more than anyone should, it’s safe to say
that these things matter.
As I noted in the methods section, the
authors of the current meta-analysis
took a very unconventional statistical
approach. It should also be noted that
they got standard deviation and standard
error mixed up for Jung et al (9) and
56
Figure 1
Re-calculated forest plot
Study
Effect size
Jung 2018
0.67 [0.02, 1.32]
Fairbairn 2018
-0.29 [-0.81, 0.23]
Close 2013b
0.26 [-0.99, 1.50]
Close 2013a (high dose)
-0.05 [-1.08, 0.98]
Close 2013a (low dose)
0.13 [-0.77, 1.03]
Wyon 2016
0.58 [-0.23, 1.39]
Pooled effect
0.20 [-0.20, 0.59]
-1.5
-1
-0.5
0
0.5
1
1.5
2
Standardized mean difference
omitted the higher-velocity leg extension data from Jung et al (9) and Wyon
et al (10) without explanation or justification. Taken together, we have multiple
justifiable reasons to disregard the values calculated in the original paper.
With these considerations in mind, I
went ahead and re-crunched the numbers
in a way that I find to be more informative. I calculated Hedges’ g as my effect
size metric, but its interpretation is extremely similar to Cohen’s d, so I’m just
going to use “d” as my general effect size
symbol throughout this article. To calcu-
late effect sizes, I compared the change
(pre to post) in the supplement group to
the change (pre to post) in the placebo
group. I used the baseline standard deviation for effect size calculations, and
I assumed a within-study correlation of
0.8 when aggregating multiple effect
sizes from a single sample. With this
approach, the overall pooled effect size
ends up being 0.20 (p = 0.34), and the
forest plot is presented in Figure 1.
The authors of the current meta-analysis also split the data set to independently look at bench press results and leg
57
extension results. If we do that with
the re-calculated values, the effect size
for bench press outcomes is -0.12 (p =
0.54), and the effect size for leg extension outcomes is 0.63 (p = 0.01).
Interpretation
Vitamin D supplementation has become somewhat popular among lifters,
likely because low vitamin D levels tend
to be quite common. For example, even
among healthy athletes, one recent meta-analysis reported that 56% of subjects
sampled had inadequate vitamin D levels, which was operationally defined as
blood 25(OH)D levels below 32 ng/mL
(80 nmol/L) (11). Other studies have
shown up to 57%, and even 62%, of
athlete samples to have deficient or insufficient vitamin D levels (12). That’s
pretty troubling, as low vitamin D levels
have been linked to depression, cognitive decline, poor bone health, and decreased neuromuscular function (2).
Specifically, vitamin D levels tend to be
lower during the winter months, and in
individuals who have minimal direct exposure to sunlight, live at high latitudes,
or frequently wear sunblock with a high
sun protection factor. It’s frequently said
that vitamin D levels are typically lower
in individuals with darker skin pigmentation, but Dr. Helms made me aware of
some research indicating that it might
not be that simple (13). In short, individuals with darker skin pigmentation may
have lower levels of total blood 25(OH)
D concentrations, despite having similar
bone density and similar levels of bioavailable 25(OH)D. This is important,
because not all of the 25(OH)D in our
blood is bioavailable, and it’s the bioavailable 25(OH)D that’s really driving
the positive effects of vitamin D.
As noted by Dahlquist et al (2), there
are very plausible reasons to believe
that correcting vitamin D deficiency
or insufficiency would have a positive
impact on performance. For example,
multiple studies have found correlations
between blood vitamin D levels and aerobic fitness (VO2max), and one study
found that vitamin D supplementation
increased VO2max (14), possibly by influencing oxygen’s binding affinity with
hemoglobin. There is also observational and experimental evidence linking
vitamin D to muscle force production,
which may be related to an increase in
the size and number of type II muscle
fibers or enhanced calcium sensitivity of
the sarcoplasmic reticulum. Much of this
research has been conducted in samples
of older adults; such studies typically
observe notable deficits in neuromuscular function as a result of vitamin D deficiency, which is robustly restored following vitamin D supplementation (15).
Other observational and experimental
studies have linked vitamin D to higher testosterone levels, reduced post-exercise inflammation, and more rapid
recovery from intense exercise (2). In
58
summary, there is reason to believe that
vitamin D may positively impact a variety of exercise performance outcomes
due to its effects on sarcoplasmic reticula, testosterone, hypertrophy, recovery,
and even oxygen delivery.
When I first saw the results of the current meta-analysis, I was pretty skeptical. The effect sizes just seemed way
too large and inconsistent, and further
digging verified that some additional
number-crunching was warranted. After
re-running the analysis, this literature
is much more in line with what I would
have expected. The overall effect size is
a very realistic d = 0.20, and the overall
analysis was not statistically significant.
However, if we look a little bit closer at
the results, a couple of interesting patterns appear.
The first pattern is pretty intuitive: The
studies with the three largest effect sizes were the studies reporting the lowest
baseline vitamin D levels in the supplement group. In each of these studies, the
baseline value for the supplement group
was under 14 ng/mL, while the other
three studies had baseline values above
20 ng/mL. By far, the least impressive
results were reported by Fairbairn et al
(16), with an effect size of -0.29. Their
supplement group had the highest baseline vitamin D levels by far, with an
initial value of over 37 ng/mL. To contextualize that, no other group receiving
supplements in this meta-analysis had a
baseline value over 21.2 ng/mL. In addi-
tion, while there is some ongoing debate
on exactly what the “ideal” range of
blood vitamin D levels is, 37 ng/mL is
considered sufficient under every set of
recommendations that I’ve come across.
The second pattern is pretty intriguing: The studies within this meta-analysis seem to indicate that vitamin D was
beneficial for lower-body exercise, but
not upper-body exercise. This was also
reported in a recent meta-analysis by
Zhang et al (17), but a 2015 meta-analysis by Tomlinson et al (5) reported
nearly identical effects for a variety of
upper-body and lower-body exercises
following vitamin D supplementation.
Of course, for the current set of data, it’s
possible that the explanation is simply
that the studies looking at lower-body
exercises coincidentally happened to, on
average, report lower baseline vitamin
D levels. It’s also possible that the observed difference between upper-body
and lower-body results may relate to
physiological explanations. For example, Zhang et al (17) speculated that lower-body musculature could be more responsive to vitamin D supplementation
due to greater vitamin D receptor density in those particular muscle groups, or
due to physiological differences related
to the fact that the lower-body musculature is much more heavily involved in
activities of daily living. Despite these
possibilities, I have a hunch that this apparent difference could be explained by
research methods.
59
In the current study, upper-body
strength was exclusively defined as
bench press strength, whereas lower-body strength was defined as isokinetic leg extension. Isokinetic leg extension
doesn’t really mimic the way we train in
the gym or compete on the platform, but
it’s awesome for research purposes. You
can control the speed of contraction, the
range of motion, and every joint angle
imaginable, for a measurement that can
be reliably replicated at multiple visits.
In addition, you’re taking a sensitive,
granular torque measurement, down to
the exact Newton meter. With bench
press, things are different. Setups can
vary from day to day. Participants know
the load on the bar, have some degree of
an emotional connection to it, and deep
down, they probably want their post-test
value to be higher than their pre-test value, despite not knowing what treatment
group they’re in. It’s much more difficult to standardize the movement and
to ensure that you’re getting a perfectly
equivalent, maximal effort at all visits.
In addition, how much can we realistically expect an athlete’s (note: typically
well-trained, but not hyper-focused on
bench pressing) bench press to increase
from vitamin D supplementation over
the span of a fairly short-term study?
Many labs lack fractional plates, so for a
number of subjects, testing probably approximated a categorical variable: they
could either add another 1.25kg plate to
each side, or maybe two, or maybe none.
VITAMIN D SUPPLEMENTATION
CAN HAVE A SMALL BUT
POSITIVE EFFECT ON STRENGTH
OUTCOMES, PARTICULARLY IF
SUPPLEMENTATION IS BRINGING
YOU FROM INSUFFICIENT
VITAMIN D LEVELS TO
SUFFICIENT VITAMIN D STATUS.
Perhaps the strongest evidence supporting this theory is presented by Tomlinson et al (5). They looked at a variety
of upper body and lower body outcomes
following vitamin D supplementation,
using a broader selection of studies than
the current meta-analysis. The pooled
effect sizes for upper body results and
lower body results were virtually identical. However, both the upper body and
lower body categories included exercise tests that used gym machines, free
weights, and dynamometers (handgrip
or isokinetic). For the upper body outcomes (eight total), the two lowest effect sizes were from tests using gym
machines or free weights, with the six
highest effect sizes coming from dynamometry. For the lower body outcomes
(eight total), the three lowest effect sizes
were from tests using gym machines or
60
IF YOU SUSPECT THAT YOUR
VITAMIN D IS LOW, THE
BEST APPROACH IS TO GET
YOUR BLOOD TESTED AND
WORK WITH A QUALIFIED
HEALTHCARE PROFESSIONAL
TO GET A SUPPLEMENTATION
PLAN TOGETHER.
free weights, with the five highest effect
sizes coming from dynamometry. Further, a 2013 study (18) sought to determine if blood vitamin D levels correlated
with upper body or lower body strength
measurements in a sample of 419 men
and women aged 20-76 years. Notably,
all measurements were taken via dynamometry. When controlling for age and
sex, blood vitamin D level was significantly associated with both arm and leg
strength. If anything, the relationship
was more consistent for upper-body
strength than lower-body strength after
controlling for additional covariates.
The studies included in this meta-analysis suggest that vitamin D supplementation can have a small but positive effect on strength outcomes, particularly
if supplementation is bringing you from
deficient or insufficient vitamin D levels to sufficient vitamin D status. While
it’s true that effects appear to be more
pronounced in lower body exercise than
upper body, I’m inclined to believe that
this is an artifact of the measurement
techniques used rather than a “real”
physiological difference. As I noted previously, there’s a bit of a debate
regarding what “sufficient” really is;
some people suggest that blood levels of
25(OH)D should be above 20 ng/mL (50
nmol/L), while other suggest it should
be above 30 ng/mL (75 nmol/L). However, as with most things in physiology,
more is not always better. Vitamin D
enhances calcium absorption from the
gut, in addition to increasing mineralization and bone resorption (that is, the
process by which bone tissue is broken
down and its minerals are released into
the blood) by stimulating bone cells to
produce receptor activator nuclear factor-kB ligand. As a result, chronically
high vitamin D levels could potentially
lead to excessive blood calcium levels,
which could increase the risk of kidney
stones or cardiovascular issues related
to vascular calcification (2). To be fair,
serum 25(OH)D concentrations below
140 don’t seem to be associated with
high blood calcium levels, and acutely
observable adverse effects typically aren’t reported until blood 25(OH)D levels
get up around 200 nmol/L, which would
probably require a daily vitamin D dose
of around 40,000 IU per day (2). None-
61
APPLICATION AND TAKEAWAYS
Maintaining sufficient blood vitamin D levels definitely seems like a good idea,
both for health and performance. The studies within this meta-analysis suggest
that vitamin D supplementation can have a small but meaningful effect on strength
performance, but only if supplementation is bringing your suboptimal baseline
vitamin D levels up into the optimal range. There is some evidence suggesting that
effects are more pronounced in lower-body strength tasks than upper-body tasks,
but I suspect this is more of a methods issue than a physiology issue. Finally, it’s
important to remember that more vitamin D isn’t always better. If you suspect that
your vitamin D is low, the best approach is to get your blood tested and work with a
qualified healthcare professional to get a supplementation plan together.
theless, the take-home point remains
the same: You don’t want your vitamin
D levels to be too low or too high. Finally, individuals with a relatively high
degree of skin pigmentation might want
to rely on metrics other than total blood
25(OH)D levels to determine if they
should consider supplementation. In my
opinion, the best approach to managing
your vitamin D levels with confidence
is to get some valid blood testing done,
and put a supplementation plan together
with your doctor or otherwise qualified
healthcare practitioner.
Next Steps
For lifters, it looks like there are two
key questions to be answered in the near
future. When it comes to blood vitamin D levels, there still isn’t a consensus about how much is enough. So, it’d
be great to more conclusively identify
the optimal range of blood vitamin D
levels in which neuromuscular perfor-
mance is optimized. In addition, I’d like
to see some follow-up work investigating the apparently differential responses between upper-body and lower-body
musculature. Ideally, we’d see studies that involve both upper-body and
lower-body measurements within the
same subjects, using both free weights
and dynamometry, to figure out if the
observed difference in the current meta-analysis is attributable to physiology
or measurement precision. For the free
weight measurements, it’d be great if researchers blind the loads being used and
utilize fractional plates, which would
serve to minimize confounding effects
from psychological factors and enhance
the precision of 1RM estimates.
62
References
1. Han Q, Li X, Tan Q, Shao J, Yi M. Effects of vitamin D3 supplementation on serum 25(OH)
D concentration and strength in athletes: a systematic review and meta-analysis of randomized controlled trials. J Int Soc Sports Nutr. 2019 Nov 26;16(1):55.
2. Dahlquist DT, Dieter BP, Koehle MS. Plausible ergogenic effects of vitamin D on athletic
performance and recovery. J Int Soc Sports Nutr. 2015;12:33.
3. Siddique U, Rahman S, Frazer AK, Howatson G, Kidgell DJ. RETRACTED ARTICLE: Determining the Sites of Neural Adaptations to Resistance Training: A Systematic Review and
Meta-Analysis. Sports Med. 2019 Nov;49(11):1809.
4. Lukaszuk JM, Luebbers PE. 25(OH)D status: Effect of D3 supplement. Obes Sci Pract. 2017
Mar;3(1):99–105.
5. Tomlinson PB, Joseph C, Angioi M. Effects of vitamin D supplementation on upper and
lower body muscle strength levels in healthy individuals. A systematic review with meta-analysis. J Sci Med Sport. 2015 Sep;18(5):575–80.
6. Close GL, Leckey J, Patterson M, Bradley W, Owens DJ, Fraser WD, et al. The effects of
vitamin D(3) supplementation on serum total 25[OH]D concentration and physical performance: a randomised dose-response study. Br J Sports Med. 2013 Jul;47(11):692–6.
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coffee: caffeine supplementation and exercise performance-an umbrella review of 21 published meta-analyses. Br J Sports Med. 2019, ePub ahead of print.
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Vitamin D3 Supplementation on Muscle Strength in Judoka Athletes: A Randomized Placebo-Controlled, Double-Blind Trial. Clin J Sport Med. 2016 Jul;26(4):279–84.
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Med. 2015 Mar;45(3):365–78.
12. Ogan D, Pritchett K. Vitamin D and the Athlete: Risks, Recommendations, and Benefits.
Nutrients. 2013 May 28;5(6):1856–68.
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Challenges. Sports Med. 2018;48(Suppl 1):3–16.
14. Jastrzębski Z. Effect of vitamin D supplementation on the level of physical fitness and blood
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█
64
Study Reviewed: Benefits of Higher Resistance-Training Volume are
Related to Ribosome Biogenesis. Hammarström et al. (2019)
Ribosome Biogenesis Influences
Whether High Volumes Cause
More Growth
BY G RE G NUC KO LS
Higher volumes tend to lead to more muscle growth and larger strength
gains, but not everyone responds to higher volumes in the same way. A
recent study found that people who respond better to higher volumes may
do so due to an increase in ribosomal content of their muscle fibers.
65
KEY POINTS
1. Using a within-subject unilateral design, subjects trained three times per week,
performing 6 weekly sets for quads with one leg, and 18 sets with the other leg.
2. Muscle growth and strength gains were larger in the leg performing more sets,
on average.
3. On an individual level, subjects who experienced more quad growth or larger
strength gains with higher volumes also experienced larger increases in ribosome
content, while people who had smaller increases in ribosome content tended to
respond similarly with both legs to both the high and low volume protocols.
I
f you think back to 10th grade biology, you probably remember learning
that the mitochondria are the powerhouses of the cell, and not much else
(assuming you didn’t have to take more
biology classes in college). If you wrack
your memory a bit more, you may remember the ribosomes, another class of
tiny cellular organelles that are responsible for constructing proteins. Due to
their function, it may be natural to wonder whether ribosomes affect the way
people respond to training.
In the present study, 34 subjects underwent 12 weeks of training. They served
as their own controls, with one leg doing
6 sets of quad training per week, and the
other leg doing 18 sets of quad training
per week. The higher volume condition
led to larger strength gains and more
muscle growth, on average, but it only
resulted in meaningfully more growth
or meaningfully larger strength gains
in ~30-40% of the subjects. Analysis of
cellular data indicated that the subjects
who saw better results from higher volumes also experienced larger increases
in muscle ribosomal content, whereas
subjects who saw similar results from
both higher and lower volumes had
smaller increases in muscle ribosomal
content.
Purpose and Hypotheses
Purpose
The main purpose of this study was to
investigate the effects of single- versus
multi-set resistance training on strength
and hypertrophy. A secondary purpose
was to compare the effects of single- and
multi-joint training on various markers
and signaling pathways associated with
hypertrophy.
Hypotheses
No hypotheses were stated.
66
Figure 1
Study overview
3
Strength test
2
0
0
1
2
3
4
5
6
7
8
9
10
7RM
7RM
7RM
7RM
7RM
7RM
7RM
8RM
8RM
8RM
1
10RM
Muscle biopsy
10RM
Training frequency
sessions week-1
Full-body DXA and
knee-extensor muscle MRI
11
12
Week
Bars represent weekly training frequency with training intensity expressed as repetition maximum (RM)
* = one session per week was performed at 90% of prescribed RM intensities
= muscle bioposy: Before (Week 0, n=34) and after the 12-week intervention (Week 12, n=34) as well as before and after (1h) the fifth exercise session (Week 2 Pre-Ex and Post-Ex, n=33)
= strength test: before the intervention (Week 0, n=34), during week 3, 5 and 9 weeks of training (n=18), and after finalization of the intervention (Week 12, n=34)
Baseline strength was determined as the highest value obtained during two test sessions performed prior to the intervention. Body composition was measured prior to the intervention (Week 0)
and after its finalization (Week 12, n=34) using full-body DXA and knee-extensor muscle MRI
Subjects and Methods
Subjects
34 subjects completed the study, including 16 males and 18 females. All
were healthy but untrained.
Experimental Design
A basic overview of the study can
be seen in Figure 1. Briefly, the study
started with a body composition and
quadriceps muscle size assessment using DEXA and MRI. This was followed
by two pre-training strength testing
sessions and a vastus lateralis biopsy
(to assess all of the various molecular
variables the researchers were interest-
ed in) obtained in a rested state. After
the pre-training testing was completed,
subjects trained for 12 weeks. Strength
was re-assessed during the study during
weeks 3, 5, and 9, with a post-test occurring after week 12. Additional biopsies were performed before and one
hour after the fifth training session, and
after the completion of the training intervention. Finally, the study ended with
post-training DEXA and MRI scans to
assess changes in body composition and
quad size.
The training intervention consisted of
12 weeks of full-body training. However, the upper body training (consisting
of bench press, pull-downs, shoulder
press, and seated rows) was the same
67
Volume-dependent effects on muscle mass and strength
0
30
15
0
-15
Week 12
0
10
Week 9
25
20
Week 5
Multiple-set
Single-set
0
10
5
0
30
Week 3
0
50
Multiple-set
1
75
Single-set
CSA change (cm2)
4
E
Mean difference (%-points 95% CI)
2
Mean difference (cm2 95% CI)
8
Average strength change (% from baseline)
D
Strength increase from
Week 0 (% ± 95% CI)
B
Paired difference
(%-point ± 95% CI)
Figure 2
Training volume-dependent changes in muscle mass and strength after 12 weeks of resistance training, evident as larger increases in knee-extensor muscle CSA (measured using MRI,
A and B) and larger increases in one-repetition maximum knee-extension and leg-press, isometric isokinetic knee-extension strength in the multiple-set leg (C). A weighted average of
all strength measures (D) was used to study the time course of strength changes (n=18) showing a gradually increasing difference between volume conditions (in favour of multiple-set
training) until Week 9, with no further increase to week 12 (E). Summary values (circles) are estimated means ± 95% CI. Triangles signifies mean paired differences ± 95% CI.
for all subjects. For lower body training,
the subjects performed unilateral leg
press, unilateral leg curls, and unilateral knee extensions. One leg performed
one set per exercise, while the other leg
performed three sets per exercise. Thus,
each subject served as their own control.
Subjects trained three times per week,
with loads progressing from 10RM loads
to 7RM loads. One day per week, training loads were reduced by 10% while
maintaining the same rep target (so the
subjects wouldn’t burn themselves out
by doing multiple sets to failure for multiple exercises three days per week).
Findings
The multi-set condition led to larger strength gains (~22% vs. ~29%) and
more hypertrophy (3.59 vs. 5.21% increase in quad CSA). Ratings of perceived exertion (effort-based not repsin-reserve based) were greater for the
multi-set condition, but the difference
actually wasn’t particularly large (7.09
± 1.95 vs. 6.22 ± 1.82). The multi-set
condition also led to a greater interconversion of type IIX to type IIA fibers.
Of the molecular variables analyzed,
the most important seemed to be total
RNA levels in muscle. Total RNA is
68
Figure 3
Total RNA per tissue weight
(ng · mg-1)
480
††††
*
††
420
Single-set
Multiple-set
360
300
Week 0
Week 2
Week 12
† = significant change from Week 0, * = significant difference between conditions
strongly associated with ribosome levels, since most of the RNA in a cell at
any given point in time is ribosomal
RNA, so an increase in cellular RNA
levels indicates that ribosomal content
has increased. The multi-set condition
led to larger increases in total RNA per
gram of muscle tissue.
13 subjects experienced meaningfully larger increases in quad CSA (larger
than the smallest worthwhile change;
2.7% in this study) in their multi-set
leg, and 16 subjects experienced mean-
ingfully larger increases in strength (at
least 4.5% larger strength gains) in their
multi-set leg [9]. Conversely, only three
subjects experienced meaningfully larger increases in quad CSA, and only one
subject experienced meaningfully larger
increases in strength in their single-set
leg.
Of the variables analyzed, total RNA
content during week two of training
(from the biopsies taken before the
fifth training session) was the strongest
predictor of whether subjects would
69
Figure 4
12
750
CSA
Total RNA (ng x mg-1)
Multiple-set (%-change)
A
8
4
0
0
4
8
12
250
Single-set (%-change)
40
20
0
0
S
M
S
M
S
M
S
M
750
Strength
Total RNA (ng x mg-1)
Multiple-set (%-change)
B
60
500
20
40
60
Single-set (%-change)
500
250
Benefit of multiple-set
Single-set
No benefit of multiple-set
Multiple-set
respond more positively to multi-set
training than single-set training. In other words, ribosomal content wasn’t necessarily predictive of whether people
would respond well or poorly to training in general; however, the subjects
that experienced larger increases in ribosome content when doing multi-set
training were more likely to experience
disproportionate benefits from multi-set
training, whereas the subjects that experienced smaller increases (or decreases)
in ribosome content were more likely to
experience similar gains from both single-set and multi-set training.
Finally, while there was a large spread
in individual strength and hypertrophy
responses, the correlations between in-
70
dividual responses to single-set and
multi-set training were strong (r = 0.8
for strength and r = 0.75 for hypertrophy). In other words, some people simply responded better or worse to training
in general, independent of training volume.
Interpretation
Before discussing the findings, I just
want to make one thing clear about the
training protocol: the single set condition was still performing six quad-focused sets per week (one set of leg press
and one set of knee extensions, three
times per week), compared to 18 for the
multi-set group. So, this study wasn’t
like some other volume studies where
the low-volume condition is using a
pitifully low volume of only 1-2 sets per
week. Six sets probably isn’t enough to
optimize growth, but it’s certainly within the range of “reasonable” volume, especially for untrained lifters. Conversely, there’s recently been discussion on
the science-based side of the fitness industry about how much volume is “too
much,” with speculation that per-session volume may be more important
than weekly volume (to a point) when it
comes to non-functional overreaching.
We recently reviewed a pair of studies
that found that just 5-10 sets per week
seemed to work best when frequency
was low (once per muscle group per
week), with diminished returns at 15-20
sets (2, 3). In the present study (1), the
higher volume group was doing 18 sets
of quad work per week, but it was split
over three sessions, allowing per-session volume to remain reasonable, and
thus yield larger gains.
I’m not incredibly interested in rehashing the Great Volume War of early 2019,
however. Rather, I simply found this
study interesting because it’s one of the
few studies we have investigating mechanistic reasons why some people – but
not all people – respond better to certain training stimuli. If this were a typical study in our field, the big takeaway
would just be that higher volumes tend to
promote more muscle growth and larger strength gains than lower volumes (4,
5). There’s already plentiful evidence
for both of those recommendations (to a
point). However, this study takes things
a step further: It specifically quantified
how many people made meaningfully
larger gains with higher volume, and it
also examined predictors of responding
better to higher volumes.
The first advantage – being able to see
how many individuals actually benefited from higher volumes – was only possible due to the within-subject unilateral
training design. Such a design (where
one arm or leg does one training program, while the other arm or leg does
another training program) isn’t ideal for
investigating strength gains due to the
cross-education effect, but it’s an excellent model for studying hypertrophy.
71
Table 1
Hypertrophy
Lower volume superior
Higher volume superior
Higher volume superior
Strength
Lower volume superior
18%
24%
6%
18%
29%
3%
3%
0%
0%
Probability of each outcome, from the present study. I've color coded the outcomes based on my personal opinions. Green outcomes are "good" outcomes if you tried
higher volumes: beneficial for both size and strength, or beneficial for size or strength with a neutral effect on the other outcome. White outcomes are only good if you
legitimately don't care about one of the outcomes. In other words, if you only cared about hypertrophy and didn't mind making slower strength progress, the 3% chance
of those simultaneous outcomes (bottom left) could still be seen as a positive outcome if using higher volumes, though it would be a negative outcome if you value both
size and strength. The red outcomes are bad outcomes: extra work with no extra results, or extra work with worse results. Note that the odds of getting one of the three
good outcomes is high (60%), while the odds of getting one of the truly bad outcomes (more work, worse results) is low (3%). However, the single most likely outcome
(middle square: 29%) is doing extra work and not having either better or worse results to show for it.
Since each subject serves as their own
control or comparator, you virtually eliminate sampling variability, and you automatically gain a considerable amount
of statistical power (since you can run
analyses like paired t-tests instead of independent t-tests). You can also simply
count the individuals who saw meaningfully better results on one program versus the other. In the present study (1),
13 out of 34 subjects experienced meaningfully more hypertrophy when training with higher volumes, while 16 out
of 34 experienced meaningfully larger
strength gains. Only 6 out of 36 subjects experienced meaningfully more
hypertrophy and meaningfully larger
strength gains. 23 subjects in total experienced meaningfully more hypertrophy
or meaningfully larger strength gains.
That leads to an interesting conclusion,
which I personally find quite intuitive,
but which may be surprising if you don’t
coach people and mostly just pay attention to differences in group means when
reading research: a decent chunk of the
subjects in this study would essentially
be wasting their time by trying to train
with high volumes. For subjects whose
main goal was muscle growth, tripling
training volume would only yield a ~2
in 5 chance of meaningfully increasing
quad hypertrophy. For subjects whose
main goal was strength, tripling training volume would only yield a ~1 in
2 chance of meaningfully increasing
strength gains. For subjects with both
strength and physique goals, they had a
~2 in 3 chance of higher volumes doing something useful, but only a ~1 in 6
chance of higher volumes boosting both
muscle growth and strength gains. Now,
I don’t think you should necessarily assume that those ratios will apply to all
possible training tweaks in all populations. For example, if you want to increase strength in the short run, and you
currently train mostly with 60% 1RM
loads, I’d bet there’s a much higher than
1 in 2 chance that increasing your aver-
72
age training intensity to 80% 1RM will
increase your rate of strength gains. Or,
if instead of comparing 6 sets per muscle group per week to 18 muscle groups
per week, if you were increasing your
volume from 1 set per week to 8 sets, I’d
bet that there’s a much higher than 2 in
5 chance of increasing your rate of muscle growth. It’s also worth noting that,
in this study, higher volumes weren’t
detrimental for many subjects. There
was only a ~1 in 11 chance of growing
more with lower volumes, and a 1 in 34
chance of having larger strength gains
with lower volumes. However, low odds
are still non-zero odds. A level of training volume that’s superior, on average,
may prove to be excessive and detrimental for you as an individual. Finally,
there was a ~1 in 2 chance that higher
and lower volumes would both result in
similar hypertrophy and strength gains
in the present study. You can interpret
that one of two ways, depending on
how lofty your goals are. You could say
“there’s a ~90-97% chance that increasing volume will produce neutral-to-positive results. Increasing volume seems
like a no-brainer.” Or, you could just as
reasonably say, “there’s a ~50% chance
that increasing volume won’t meaningfully improve my results (for one characteristic; ~33% chance it won’t improve
either hypertrophy or strength), and if
my results do improve, the improvement
likely won’t be commensurate with the
additional effort (increasing volume by
200% to boost strength gains by ~30%
THE RESEARCHERS FOUND
THAT IF RIBOSOME BIOGENESIS
INCREASED SUBSTANTIALLY
WITHIN THE FIRST COUPLE
WEEKS OF TRAINING, SUBJECTS
WERE MORE LIKELY TO RESPOND
BETTER TO HIGHER VOLUMES
THAN LOWER VOLUMES.
and muscle growth by ~45%), and that
doesn’t sound like a deal worth making,
since my life doesn’t revolve around the
gym.” Once you enter the realm of probabilities, and then sprinkle in differences
in goals and values, it’s not reasonable
to expect everyone to respond to these
findings the same way.
As mentioned, the second benefit of
this study is that it examined mechanisms to predict what style of training
people would respond best to. The researchers found that if ribosome biogenesis increased substantially within
the first couple weeks of training, subjects were more likely to respond better
to higher volumes than lower volumes;
conversely, if the subjects experienced
a smaller increase in ribosome biogenesis or no increase, they were likely to
73
EVEN THOUGH WE’RE STILL A
FEW STEPS AWAY FROM THE
RIBOSOME FINDINGS IN THIS
STUDY BEING ACTIONABLE, I’M
STILL PRETTY EXCITED ABOUT
THEM, SIMPLY BECAUSE SO
LITTLE RESEARCH HAS LOOKED
INTO FACTORS THAT INFLUENCE
THE STYLE OF TRAINING
SOMEONE RESPONDS BEST TO.
respond similarly to both high and low
volumes. That’s not of much practical
use to us yet (unless you got some muscle biopsies around the time you started training), but it may prove valuable
down the line. If we find that some characteristics that can be assessed non-invasively predict the ribosomal response
to training (i.e. some genetic variants),
we could then potentially predict whether you’re someone who would benefit from training with high volumes, or
whether lower volumes are more appropriate for you (and perhaps manipulating some other factors like frequency or
proximity to failure when trying to increase growth or strength gains). Even
though we’re still a few steps away from
the ribosome findings in this study being
actionable, I’m still pretty excited about
them, simply because so little research
has looked into factors that influence
the style of training someone responds
best to. For example, a study by Beaven and colleagues found that acute testosterone-to-cortisol ratios predicted
whether people would respond better
or worse to four different training programs (6), though I don’t think the acute
hormonal responses were necessarily
the causative factor driving the different
training responses. A study by Jones et
al found that a (conveniently) proprietary genetic algorithm could predict
whether people could respond best to
power-type or strength endurance-type
training (7); I’m a little skeptical of that
study since some of the researchers who
ran the study work for the company that
owns the proprietary algorithm, and
they didn’t make the algorithm public
to let other researchers attempt to replicate their findings. There’s at least one
study (8) finding that different variants
of the ACE gene predict whether people
benefit more from moderate versus low
training volumes (similar to the present
study). On the resistance training side of
things, that’s all we have so far, in addition to the present study’s ribosomal
findings. It’s clear that different people
do, in fact, respond better or worse to
various training styles, but there’s just
not much research examining the potential mechanisms. Some people do bet-
74
APPLICATION AND TAKEAWAYS
1. Overall, higher volumes still tend to promote more muscle growth and larger
strength gains.
2. Not everyone benefits from higher training volumes. Some percentage of people
respond similarly well to both lower volumes (to a point) and higher (to a point). A
small minority of people actually respond better to low volumes.
3. Whether or not you’re able to pump out a bunch of new ribosomes may predict
whether ramping up training volume will help you build more muscle and strength.
ter with higher or lower volumes, some
people do better with higher or lower
frequencies, some people do better with
higher or lower intensities, and without
simply troubleshooting, we just don’t
yet have many good ways to predict the
style of programming an individual will
respond best to. The present study (1)
was approximately the fourth step in a
sparse line of research leading toward a
future where, hopefully, we can better
predict the styles of programming that
will allow each individual to thrive.
that would be a big improvement over
measuring changes in ribosome content
– which requires multiple muscle biopsies – since you can sequence a genome
from just a cheek swab or blood draw.
Next Steps
There’s already a decent body of research looking for genes that predict
how well people will respond to training
in general, but we’re generally lacking
studies examining whether genes can
predict what style of training an individual will respond best to (except for
the Jones study with the proprietary
algorithm). If we found that gene testing could be useful for this application,
75
References
1. Hammarström D, Øfsteng S, Koll L, Hanestadhaugen M, Hollan I, Apro W, Whist JE, Blomstrand E, Rønnestad BR, Ellefsen S. Benefits of higher resistance-training volume are related
to ribosome biogenesis. J Physiol. 2019 Dec 8.
2. Barbalho M, Coswig VS, Steele J, Fisher JP, Giessing J, Gentil P. Evidence of a Ceiling
Effect for Training Volume in Muscle Hypertrophy and Strength in Trained Men - Less is
More? Int J Sports Physiol Perform. 2019 Jun 12:1-23.
3. Barbalho M, Coswig VS, Steele J, Fisher JP, Paoli A, Gentil P. Evidence for an Upper
Threshold for Resistance Training Volume in Trained Women. Med Sci Sports Exerc. 2019
Mar;51(3):515-522.
4. Schoenfeld BJ, Ogborn D, Krieger JW. Dose-response relationship between weekly resistance training volume and increases in muscle mass: A systematic review and meta-analysis.
J Sports Sci. 2017 Jun;35(11):1073-1082.
5. Ralston GW, Kilgore L, Wyatt FB, Baker JS. The Effect of Weekly Set Volume on Strength
Gain: A Meta-Analysis. Sports Med. 2017 Dec;47(12):2585-2601.
6. Beaven CM, Cook CJ, Gill ND. Significant strength gains observed in rugby players after
specific resistance exercise protocols based on individual salivary testosterone responses. J
Strength Cond Res. 2008 Mar;22(2):419-25.
7. Jones N, Kiely J, Suraci B, Collins DJ, de Lorenzo D, Pickering C, Grimaldi KA. A genetic-based algorithm for personalized resistance training. Biol Sport. 2016 Jun;33(2):117-26.
8. Colakoglu M, Cam FS, Kayitken B, Cetinoz F, Colakoglu S, Turkmen M, Sayin M. ACE
genotype may have an effect on single versus multiple set preferences in strength training.
Eur J Appl Physiol. 2005 Sep;95(1):20-6.
9. “Smallest worthwhile change” may sound like a value judgement, but it’s essentially just an
increase of 20% of the group’s pre-training standard deviation for a particular measure. It’s
essentially the cut off between a “trivial” and “small” Cohen’s D effect size, applied to an
individual instead of a population. In other words, if the standard deviation for bench press
strength in a group is 10kg, the smallest worthwhile change in bench press strength for a
subject in that group would be 2kg.
█
76
Study Reviewed: Acute Effects of Knee Wraps/Sleeve on Kinetics, Kinematics
and Muscle Forces During the Barbell Back Squat. Sinclair et al. (2019)
Are Knee Sleeves or Knee
Wraps Right for You?
BY MIC HAE L C . ZO URD O S
We know that knee wraps may help you lift more, but what about knee
sleeves? And, how do both of these acutely affect squat biomechanics?
This article answers some of those questions and discusses when sleeves
and wraps are appropriate outside of the typical powerlifting context.
77
KEY POINTS
1. This study compared the acute kinetics and kinematics of squatting with knee
wraps, knee sleeves, and nothing on the knees.
2. The main finding was that muscle forces tended to be lower when squatting with
knee wraps versus sleeves or nothing. The subjects also perceived both sleeves
and wraps to improve stability, but perceived sleeves to increase squatting comfort
and wraps to decrease it.
3. The decrease in muscle forces when wearing wraps suggests lower long-term
hypertrophy when squatting with wraps; however, this study used the same exact
load in the wrapped and unwrapped conditions. This article discusses what may
happen if a higher load was used for wraps and which of these options (nothing,
wraps, or sleeves) might be right for your goals.
M
ASS has yet to discuss the use
of knee sleeves and knee wraps.
We don’t need a study to tell us
that knee wraps can acutely increase the
amount you can lift, although those studies do exist (2, 3). But do wraps or sleeves
alter the acute kinetics and kinematics,
or even the perception of stability, in the
squat? The answers can provide us insight into when sleeves and wraps might
be appropriate outside of just the typical powerlifting context. The reviewed
study from Sinclair et al (1) attempted
to answer these questions. Sinclair had
15 trained men perform 5 reps at 70%
of their bare-kneed squat one-repetition
maximum (1RM) under four different
conditions: 1) No equipment (control),
2) competition (stiffer) knee wraps, 3)
training (more flexible) knee wraps, and
4) Strength Shop Inferno Neoprene knee
sleeves. Muscle forces and subjective
ratings of comfort and stability were
gauged after each condition. In general, muscle forces (hamstring, glutes,
and calves) were significantly greater in
the control condition versus both knee
wrap conditions; however, there were
no differences in muscle forces between
the control and knee sleeve conditions.
Both the wraps and sleeves improved
subjective knee stability compared to
the control condition, but the sleeves
improved perceived comfort while the
wraps reduced it. On the surface, it
seems that knee wraps may attenuate
muscle growth if worn consistently by
decreasing engagement of the working
musculature. However, we would need
a long-term study to truly determine
this. A positive spin on the data would
be to say that knee wraps might be good
for longevity by reducing muscle forces.
As with most debates, what to wear on
your knees seems to be goal-dependent,
and it doesn’t have to be an all-or-noth-
78
Table 1
Subject characteristics
Subjects
Age (years)
Height (cm)
Body mass (kg)
Squat experience (years)
Squat 1RM (kg)
15 men
23.0 ± 3.47
181 ± 7
85.83 ± 17.10
>2
122.62 ± 24.43
Subject characteristics from Sinclair et al. 2020 (1)
ing thing. This study does have a major
design flaw that keeps us from inferring
too much. This article will discuss that
flaw and examine the totality of literature on sleeves and wraps to theorize the
appropriate times to wear each outside
of just powerlifting.
Purpose and Hypotheses
Purpose
The purpose of this study was to compare acute squat kinetics and kinematics
(muscle forces, ground reaction forces,
velocity, etc.) and the perception of comfort and stability between squatting with
knee wraps, knee sleeves, and nothing
on the knees.
Hypotheses
No hypotheses were provided.
Subjects and Methods
Subjects
15 men with at least two years of back
squatting experience, but no experience
using knee wraps, participated. The paper did not specify if the subjects had
experience with knee sleeves, but I
would assume not. The available subject
details are in Table 1.
Protocol
Subjects performed four different
squat conditions on one day in a counterbalanced order with three minutes
between conditions. In all four conditions, subjects squatted five reps on
the high-bar back squat at 70% of their
no-external-equipment (i.e. nothing on
the knees) 1RM. Also, a 1RM was not
actually tested; subjects told the investigators what their 1RM was. In other
words, subjects essentially selected their
own load, then used that same exact
load for all conditions. The squat conditions were: 1) Competition (stiffer)
knee wraps, 2) training (flexible) knee
wraps, 3) knee sleeves, and 4) no equipment (control). We’ll get to this later,
but aside from having subjects self-report their 1RM, it seems like a design
flaw to use the same load for each condition since knee wraps have a significant
effect on strength.
The knee wraps used were the SBD
Apparel competition and training knee
wraps. Both sets of wraps were International Powerlifting Federation (IPF)-approved and were available in all sizes for
the subjects to use. The same researcher
79
Table 2
Kinematic outcome measures
Outcome Measure
Description
Muscle forces
Estimated for the quads, glutes, hamstring, and calves
(gastrocnemius and soleus). This is the force the muscle
produced recorded in Newton Seconds (N/kg s). This
was assessed on both the eccentric and concentric
portions of the lift.
Knee forces
Peak knee force, patellar tendon force, and
patellofemoral force were all calculated to determine the
stress of each condition on the knee joint.
Ground reaction force
Force exerted on the ground by the lifter. This was
assessed on both the eccentric and concentric portions
of the lift.
Rate of force development
Velocity / duration
motor unit or how quickly someone can produce force.
This was assessed for the quads, glutes, hamstrings,
and calf muscles.
Both average concentric and eccentric velocity (m/s)
and concentric and eccentric duration (seconds) were
calculated during each condition
Joint range of motion
tied the knee wraps as tight as possible
in presumably the same style prior to
each set, although the style (spiral or X)
was not specified. The knee sleeves used
were the Inferno from Strength Shop.
These sleeves are made of neoprene and
are IPF-approved. Following all four
conditions, subjects were asked which
condition they preferred to squat under.
Additionally, subjects were asked to rate
comfort and stability of each condition
compared to the control condition on a
three-point scale as follows: “1 = improved comfort/stability, 2 = no change,
3 = reduced comfort/stability.”
Kinetic and Kinematic Outcome Variables
Kinetic and kinematic outcome variables were collected by placing reflective markers on various body segments
and using an eight-camera 3D motion
capture system. Ground reaction forces
80
Table 3
Measure
Control (nothing)
Knee sleeve
Competition knee wrap
Training knee wrap
Average Concentric Velocity (m/s)
1.01±0.04
1.11±0.37
1.05±0.17
1.05±0.18
Concentric Duration (s)
1.33±0.20*
1.27±0.21
1.21±0.17
1.22±0.19
12.61±2.91#
13.00±2.70
14.17±3.69#
13.47±3.77
Concentric Quadriceps Force (N/kg s)
58.30±20.09^
54.67±16.01
51.87±19.02
53.33±22.03
Concentric Gluteus Maximus Force (N/
kg s)
24.29±9.62!
21.78±5.85
22.22±8.91
21.03±7.23
Concentric Hamstrings Force (N/kg s)
39.01±15.34!
34.74±9.58
35.61±14.02
33.97±11.58
Concentric Gastrocnemius Force (N/kg s)
7.25±3.09^
6.85±2.76^
5.97±2.54
6.39±2.16
Concentric Soleus Force (N/kg s)
15.49±6.61^
14.62±5.90^
12.75±5.42
13.64±4.61
Peak Shear Knee Force (N/kg)
7.68±2.15^
7.62±2.09^
6.90±1.82
7.25±2.20
Knee Anterior Translation (cm)
20.50±2.87^
20.49±3.56
19.07±4.06
19.93±4.45
Knee Lateral Translation (cm)
13.41±3.04^!
13.85±3.53^!
12.29±2.88
12.51±3.06
Hip Peak Internal Rotation (°)
10.80±13.19^!
11.50±13.44^!
18.78±11.21
21.19±9.29
Knee Peak Adduction (°)
8.64±5.38^!
9.27±6.86^!
17.65±6.76
17.44±6.55
Knee Peak Internal Rotation (°)
19.81±9.32^!
24.26±15.79
31.45±12.70
29.62±10.59
27.72±5.65^
27.46±6.04^
23.96±5.98
25.91±7.29
-9.14±5.13#^!
-11.43±6.90
-14.31±7.13
-12.23±4.84
Eccentric Ground Reaction Force (N/kg s)
Ankle Peak Eversion (°)
Subject characteristics from Sinclair et al. 2020 (1)
* = Significantly different than all other conditions, # = Significantly different from knee sleeve condition, ^ = Significantly different from competition wrap condition
! = Significantly different from training wrap condition.
were assessed by having subjects squat
on a force plate. Exploring every single detail of how the outcome variables
were extracted from the motion capture
is unnecessary and outside of our scope;
however, this setup allowed for a plethora of outcomes. I’ve slightly condensed
the outcome variables to those most relevant and listed them in Table 2 with a
short description for each one.
Findings
Since there were a ton of variables,
let’s cut right to the chase and present
the findings in a straightforward manner. The following paragraph presents
the findings in a nutshell, then all significant kinetic and kinematic findings are
presented in Table 3 and all subjective
findings are in Table 4.
Overall Results
1) Knee wraps and knee sleeves tended to cause a faster squat, 2) knee wraps
reduced the forces of all muscles assessed, 3) knee wraps reduced knee
joint force, 4) knee wraps reduced perceived comfort but increased stability,
5) knee wraps increased various metrics
81
Table 4
Individual response to subjective measures
Preference breakdown
Control = 3
Condition
Knee sleeve = 7*
Training wrap = 3
Competition wrap = 2
Improved comfort
Reduced comfort
No change in comfort
Improved stability
Reduced stability
No change in stability
Knee sleeve
9*
2
4
10*
2
3
Competition wrap
2
9*
4
11*
2
2
Training wrap
2
10*
3
9*
2
4
Subject characteristics from Sinclair et al. 2020 (1)
The preference breakdown is the number of lifters that preferred to squat in one condition compared to all others. Comfort and stability data reported are the number of individuals who provided a particular
response when rating each condition compared to the control (nothing).
* = Significant difference for that response within the condition.
of range of motion, and finally 6) knee
sleeves increased both comfort and stability and did not affect muscle forces of
the quads, hamstrings, and glutes.
Interpretation
Obviously, if you’re an equipped powerlifter or compete in a “raw with wraps”
division, then at least some of your training should be done with knee wraps, as
you’re concerned about perfecting the
skill of squatting with wraps. However,
what do these results suggest for everyone else? The lower muscle forces with
knee wraps suggest that knee wraps may
be suboptimal for long-term muscle
growth. On the plus side, knee wraps reduced knee shearing forces, suggesting
the potential for injury risk reduction
and greater longevity. Further, with the
exception of lower muscle forces among
the calf muscles, knee sleeves produced
pretty similar kinetics and kinematics to
squatting with nothing on your knees,
while also increasing comfort. Thus,
knee sleeves seem to have no obvious
downside for any type of squatting goal.
However, that’s the surface level interpretation.
The main flaw of this study, which
calls the surface level interpretation into
question, is that it used the same load for
each condition. Since we know that knee
wraps help you lift more (2, 3), these
findings would be more useful if a condition-specific 70% of 1RM was used
(i.e. 70% of sleeved or wrapped 1RM),
which would have most likely resulted
in a higher load being used for the wrap
conditions. I say most likely because the
present subjects didn’t have experience
with wraps, so they might not have fully
understood how to use the wraps to their
benefit. Therefore, ideally this study
would have used lifters who had experience with wraps or would have at least
familiarized the subjects with the wraps
and then used condition-specific loads.
One additional point: When the authors
calculated muscle forces, they did so
with musculoskeletal modeling. While
that is appropriate, Greg pointed out to
me that it appears the authors did not
82
include in their calculations how much
the wraps compressed the knee joint or
to what degree the wraps caused knee extension independently of the squat (if they
did, the means by which they did so isn’t
discussed at all in the paper). It seems
that in the wraps conditions, subjects
cut depth higher, which is apparent as
the concentric duration was significantly
lower in the wraps conditions versus the
control (Table 3), yet average concentric
velocity was similar between conditions.
Therefore, the modeled quadriceps force
was likely lower in the wraps conditions
simply due to the decreased range of motion. If range of motion was similar between conditions, then modeled quadriceps forces may have been similar as well
(though, if the wraps weren’t accounted
for in the modeling, the actual quadriceps
forces may have actually been even lower). It is not as clear if other muscle forces
would have been the same with a similar
range of motion, but let’s explore what
could have happened to muscle forces if
the load used in the wraps condition was
70% of the wrapped 1RM? The answer
is that we can’t really know. By my count,
there are five studies to date that are relevant to this article and which investigated
the use of knee wraps during the squat (2,
3, 4, 5, 6) and one unpublished Master’s
thesis (7) on knee sleeves and squat mechanics. I’ll tell you up front that none of
those studies solve the flaw of this study,
but let’s look at each one to determine
what the totality of literature has to say
on the topic.
THESE FINDINGS WOULD
BE MORE USEFUL IF A
CONDITION-SPECIFIC 70%
OF 1RM WAS USED (I.E. 70%
OF SLEEVED OR WRAPPED
1RM), WHICH WOULD HAVE
MOST LIKELY RESULTED IN
A HIGHER LOAD BEING USED
FOR THE WRAP CONDITIONS.
Lake et al 2012 (2)
Lake et al was the first study to examine the effect of knee wraps on acute
squat kinematics. Lake had trained men
with experience wearing knee wraps
perform 3 sets of 1 at 80% of the unwrapped max with both nothing on their
knees and while wearing wraps. So,
right off the bat, we see the same flaw as
the present study, which is that the same
load was used for both the wrapped and
unwrapped conditions. The researchers
showed that with wraps, peak power was
increased, the eccentric duration was
longer, and the concentric duration was
shorter. These findings for the concentric phase are in somewhat agreement
83
THE LITERATURE DOESN’T
SUGGEST ANY REAL DOWNSIDE
TO KNEE SLEEVES, NO
MATTER YOUR GOALS.
with the present study from Sinclair (1),
as it showed a shorter concentric duration with knee wraps. However, Lake
observed a slower eccentric, but Sinclair
did not. This was probably the case because Lake’s lifters had experience with
wraps, whereas the present lifters didn’t.
This study doesn’t add much to our understanding, but it was the first study on
the topic, so it was only designed to essentially answer the question, “do knee
wraps help you lift the same load faster”
and the answer was of course, “yes.”
Gomes et al 2014 (3)
This study doesn’t add much either. It
had 10 trained individuals perform an
isometric squat with what the researchers called “hard” knee wraps, “soft”
knee wraps, and no knee wraps. Both
knee wrap conditions produced greater
force than the no knee wrap condition.
Again, knee wraps aid in force production.
Gomes et al 2015 (4)
The second study from Gomes had
subjects perform 1 set of 3 reps at 60%
and 90% of 1RM both with and without
knee wraps. Again, the same flaw was
present, as the intensity in all conditions
was based upon an unwrapped max.
These subjects were trained, but had no
experience with wraps. Muscle activity
(EMG) of the vastus lateralis and gluteus maximus was lower in the knee wrap
condition. This finding is in line with the
lower forces in the knee wrap conditions
in the presently reviewed study. However, again, similar to the present study, we
can’t know if EMG activity would have
been lower if condition-specific loads
were used.
Eitner et al 2011 (5)
Unfortunately, this was just a conference abstract and I could not find these
data actually published. This study used
10 powerlifters, and the lifters performed
1 set of 6 reps at their 12RM both with
and without knee wraps. It is not clear
from the abstract if this 12RM was condition-specific, but I don’t believe it
was. I believe the load used in both conditions was the unwrapped 12RM, but
I cannot be 100% sure. This study did
not show any differences in concentric
or eccentric work between conditions.
Marchetti et al 2015 (6)
Marchetti investigated the effects of
different styles of wrapping on ground
reaction forces during an isometric
84
squat. This involved comparing the
“spiral” and “X” styles. No difference
between wrapping styles was found for
ground reaction force.
Trypuc 2018 (7)
This study was a Master’s thesis and
the only other study I’m aware of to date
examining knee sleeves. I do not believe this study is officially published as
of yet; thus, I’ve hyperlinked the actual
thesis. Trypuc assessed the difference
in 1RM squat strength and EMG of the
quads, glutes, and hamstrings in trained
men and women. This study found that
7mm Rehband knee sleeves did not increase 1RM and that EMG activity was
similar between conditions for all muscles except for the glutes. Gluteus maximus EMG activity was significantly
lower, but only by 1.35%, in the sleeve
versus no sleeve condition. The lower
glute activation in the sleeve condition
could suggest that wearing knee sleeves
all the time might compromise glute development over the long-term; however, I question the relevance of a 1.35%
difference. It would be quite a stretch
to suggest that such a small difference
in acute EMG activity would actually
translate to less muscle growth.
What Does All of This Mean?
In short, it means that the literature
hasn’t done all that much to move this
topic forward except to show us that
knee wraps help you lift explosively and
produce more force. Turning our attention back to the lower muscle forces in
the present study with knee wraps, if
this finding was replicated in a future
study that used condition-specific loads,
then it wouldn’t be unreasonable to suggest avoiding wraps if your main goal
is hypertrophy. However, if the lower
knee shearing force were to also hold up
with condition-specific loads, then knee
wraps could lead to greater longevity. If
your goal is hypertrophy, the safest bet
is probably to avoid knee wraps, but if
you were to wear them, I’m not sure
how much it would matter in real terms.
Squats aren’t the only lift that you are
performing, and you would still get substantial hypertrophy from squatting with
wraps. You could take the wraps off for
all of your other movements, or possibly
just wear them on higher load sets when
you want to increase your perceived stability.
In terms of knee sleeves, the literature
doesn’t suggest any real downside, no
matter your goals. I do wonder if the
SBD or Inferno sleeves were used in the
Trypuc thesis instead of Rehbands, if
1RM would have been improved, especially in lifters who usually wear them.
Nonetheless, sleeves don’t seem to have
much downside even if you aren’t a
powerlifter. In the present study, sleeves
were the “preferred” way to squat. However, to my knowledge, the researchers
didn’t clarify what the question meant.
Therefore, some could have interpret-
85
APPLICATION AND TAKEAWAYS
1. This study showed that muscle forces of the quads, hamstrings, glutes, and
calves were lower when using knee wraps versus knee sleeves or bare knees
during squats. Knee sleeves had lower muscle forces than nothing for the calves,
but similar muscle forces for the quads, hamstrings, and glutes.
2. Although these results suggest that muscle growth may be attenuated if knee
wraps are consistently used for squatting, it is imperative to remember that the
same load was used for the wrapped and unwrapped conditions. Future research
should use condition-specific loads, which would certainly mean a heavier load in
the wrapped condition. Condition-specific loads would be a truer test of muscle
forces and muscle activation.
3. Importantly, knee sleeves don’t have any downside that we can see, and they
improve comfort and stability during the squat. Therefore, at this time, it seems
that consistently wearing knee sleeves during squatting is appropriate for all
types of trainees.
ed “preferred” as most comfortable and
others as what they perceived to be the
strongest condition for them.
Before we move onto the next steps,
I’d like to reiterate that the subjects in
the present study did not have any prior
experience with wraps and that should
be rectified in future studies. The lack
of experience with wraps is almost certainly why concentric velocity wasn’t
significantly greater in the wraps conditions and could have also contributed to
the lower muscle forces.
tion-specific 1RM would suffice. If that
found significantly lower muscle forces
in the wrapped condition, then a longterm training study comparing the three
conditions for hypertrophy and strength
would then be appropriate. Subjects in
this proposed study should have at least
some prior experience using knee wraps.
Next Steps
To keep it simple, a study that replicated the current study with the following conditions: 1) control, 2) sleeves,
and 3) wraps, but which used a condi-
86
References
1. 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.
2. Lake JP, Carden PJ, Shorter KA. Wearing knee wraps affects mechanical output and performance characteristics of back squat exercise. The Journal of Strength & Conditioning
Research. 2012 Oct 1;26(10):2844-9.
3. Gomes WA, Serpa EP, Soares EG, da Silva JJ, Corrêa DA, de Oliveira FH, de Abreu Neto F,
Martins G, Vilela Junior GB, Marchetti PH. Acute effects on maximal isometric force with
and without knee wrap during squat exercise. Int J Sports Sci. 2014;4(2):47-9.
4. Gomes WA, Brown LE, Soares EG, da Silva JJ, Fernando HD, Serpa ÉP, Corrêa DA, Junior
GD, Lopes CR, Marchetti PH. Kinematic and sEMG analysis of the back squat at different
intensities with and without knee wraps. The Journal of Strength & Conditioning Research.
2015 Sep 1;29(9):2482-7.
5. Eitner JD, LeFavi RG, Riemann BL. Kinematic and kinetic analysis of the squat with and
without knee wraps. The Journal of Strength & Conditioning Research. 2011 Mar 1;25:S41.
6. Marchetti PH, Matos VDJP, Soares EG, Silva JJ, Serpa EP, Cor- rêa DA, Gomes WA (2015)
Can the technique of knee wrap placement a ect the maximal isometric force during back
squat exercise. Int J Sports Sci 5(1):16–18
7. Trypuc AA. Effects of Knee Sleeves on Knee Mechanics During Squats at Variable Depths.
█
87
Study Reviewed: Acute Capsaicin Supplementation Improved Resistance Exercise
Performance Performed After a High-Intensity Intermittent Running in ResistanceTrained Men. De Freitas et al. (2019)
The Hottest Supplement on
the Market: New Research on
Capsaicin and Strength
BY E RI C T RE X LE R
Back in Volume 1, Dr. Helms covered one of the first studies evaluating capsaicin’s
effects on lifting performance. Another one is finally here, with results suggesting
that capsaicin increases squatting strength endurance following high-intensity
running. Read on to find out if capsaicin supplementation might be worth a try.
88
KEY POINTS
1. The current study (1) found that two, 12mg doses of a capsaicinoid called capsiate
acutely improved squat repetitions completed and total weight lifted throughout
a four-set squat protocol that took place after high-intensity intermittent running.
2. This is now the second study reporting enhanced lifting performance following
capsaicinoid supplementation; one study has reported improvements in running
time trial performance, but another has reported no benefit for repeated sprint
performance.
3. The literature is far from conclusive, but it’s possible that capsaicinoids acutely
enhance lifting performance by reducing perceived pain and exertion and altering
intramuscular calcium kinetics. High doses of cayenne extract may cause
gastrointestinal distress, so 12mg doses of a concentrated capsiate product
would be a more advisable strategy for those who want to give pre-exercise
capsaicinoids a shot.
I
f you’ve been a MASS reader for a
while, then capsaicin is not new to
you. All the way back in Volume
1, Dr. Helms reviewed a study reporting that capsaicin supplementation increased repetitions completed and total
weight lifted across four sets of squats to
failure. We’re always enthusiastic about
new supplements that may improve performance, especially if (like capsaicin)
they can be found in many foods and potentially have some positive effects on
fat loss, but it’s important to see results
replicated before we get too excited. The
current study (1) was completed by the
same research group that completed the
previously mentioned capsaicin study,
but utilized a slightly different design.
In this study, participants took 12mg of
capsiate (a capsaicinoid that is very similar to capsaicin) or placebo, rested for
45 minutes, then took another 12mg dose
immediately before testing. The testing
protocol consisted of a 5km intermittent running test, followed by four sets
of squats to failure with 70% of 1RM.
Results indicated that the capsaicinoid
supplement reduced perceived exertion
and average heart rate during the running test, and increased repetitions completed and total volume load in the squat
protocol. This article discusses what we
know so far about capsaicinoids, and
whether or not you should consider adding capsaicinoid supplements (or capsaicin-rich foods) to your diet.
Purpose and Hypotheses
Purpose
The purpose of this study was “to investigate the acute effects of capsaicin
89
Table 1
Subject characteristics (n=11)
Age (years)
Height (cm)
Body mass (kg)
BMI (kg/m )
Resistance training
experience (years)
Maximum strength in
squat (kg)
Maximal aerobic power
(km·h-1)
23.3 ± 2.2
176.3 ± 5.3
79.8 ± 11
22.3 ± 2.4
3.5 ± 1.7
83.3 ± 14
12.8 ± 1.4
Data Calculated from De Feitas et al. 2019 (1)
Data are mean ± SD
supplementation on the RPE and heart
rate (HR) (mean and peak) during HIIE
(high intensity interval exercise) and resistance exercise volume performed after a HIIE in resistance-trained men.”
Hypotheses
The authors hypothesized that capsaicin would reduce Borg RPE (using the
Borg category-ratio scale ranging from
1-10) and heart rate during the interval
exercise and increase total weight lifted
during the resistance exercise test.
Subjects and Methods
Subjects
This study was completed by 11 males
with at least 1 year of resistance training
who typically trained 3-5 days per week
for at least 50-60 minutes per session.
In order to participate, all participants
had to be apparently healthy non-smokers between the ages of 20 and 30 and
could not have used dietary supplements
within six months of study participation.
Subject characteristics are presented in
Table 1.
Methods
The current study evaluated the effect
of capsaicin supplementation (24 total
mg) on multiple exercise outcomes. It
was a crossover trial, so each participant
completed two separate testing visits,
seven days apart: one in which they consumed the supplement, and one in which
they consumed the placebo. It was double-blinded and randomized, so subjects
didn’t know which pills they got each
time.
As a technical note, the supplement
was actually formulated to provide capsiate rather than capsaicin. Capsiate is
a type of capsaicinoid; it is structurally similar and activates the same receptor as capsaicin, but it’s derived from a
far less pungent cultivar of red pepper,
thereby inducing minimal heat sensation and gastrointestinal irritation in
comparison to capsaicin itself. Due to
their similarities, the authors of the current study simply referred to the supplement as “capsaicin.” I have adopted
their terminology and followed suit, but
I figured it’d be prudent to point out this
distinction.
At each testing visit, participants ingested half of their treatment for the day
(12mg) and rested for 45 minutes, followed by the other half of their treatment
90
Figure 1
Experimental design
Baseline
45 minutes rest
12mg of capsaicin
or placebo
5 minute warm-up
50% Vmax
High intensity intermittent exercise
5km (1min Vmax: 1min passive recovery)
10 minute
passive interval
12mg of capsaicin
or placebo
Squat exercise
4 sets x 70% 1RM
RPE + heart rate measured
Data Calculated from De Feitas et al. 2019 (1)
and a brief warm-up. After that, they
completed the interval training workout,
which was a 5km run completed as a series of one-minute runs at 100% of maximal aerobic power, with one minute
of passive rest in between them. Heart
rate and Borg RPE were measured at
the conclusion of the run. After 10 minutes of rest, they did four sets of squats
using 70% of their 1RM, with each set
taken to the point of concentric failure.
Participants rested for two minutes between each set. Squat repetitions were
completed with a two-second eccentric
phase and one-second concentric phase,
and an adjustable seat was used to standardize squat depth to an approximately
90° knee angle. Volume load was calculated by multiplying the load used by the
number of repetitions performed. The
study protocol is summarized in Figure
1.
Findings
In the interval training protocol, capsaicin significantly lowered RPE from 8.1
± 1.3 (placebo) to 6.9 ± 0.9 (capsaicin),
with an effect size of d = 1.0 (Table 2).
Peak heart rate was not significantly influenced (179 ± 11 bpm for capsaicin
versus 183 ± 8 bpm for placebo; p =
0.12), but mean heart rate for capsaicin
(153 ± 13 bpm) was significantly lower than the placebo condition (158 ± 12
bpm), with an effect size of d = 0.4.
As one would expect, the overall number of repetitions per set dropped over
the four-set resistance exercise protocol.
There was a significant treatment effect,
with more repetitions performed in the
capsaicin condition (34.9 ± 8.2) than the
placebo condition (30.5 ± 10.2; p = 0.02;
d = 0.48). For volume load, results (unsurprisingly) followed the same pattern.
Volume load dropped over the course of
the four-set protocol, and more volume
load was completed in the capsaicin
condition (2077.6 ± 465.2 kg) than the
placebo condition (1838.9 ± 624.1 kg; p
= 0.03; d = 0.43). These results are presented in Figure 2.
Interpretation
The implications of these findings are
91
Table 2
Rating of perceived exertion and heart rate during high-intensity
intermittent exercise for each trial
Variables
Placebo
Capsaicin
Rating of perceived exertion (points)
8.1 ± 1.3
6.9 ± 0.9†
Mean heart rate (b·min-1)
158.0 ± 12.3
153.4 ± 12.9†
Peak heart rate (b·min-1)
183.1 ± 7.7
178.7 ± 10.9
Data Calculated from De Feitas et al. 2019 (1)
Data are mean ± SD
† = statistically significant differences between capsaicin and placebo conditions
pretty straightforward: this lab group
has, for the second time, demonstrated
that capsaicin supplementation increases repetitions completed and total weight
lifted when multiple sets of squats are
taken to failure. The primary differences
between the current study (1) and their
previous study (2) relate to both the capsaicin dosing and the exercise protocol.
Last time around, they did resistance
training only and took 12mg of capsaicin
45 minutes before testing. In the current
study, the resistance training test was
preceded by a bout of high-intensity, intermittent running, and the participants
took 12mg of capsaicin at two separate
time points: 45 minutes before testing,
and immediately before testing. The
two-dose approach was used because the
current study had a longer exercise testing protocol, and capsaicin peaks in the
blood around 45 minutes after ingestion,
with nearly complete clearance from the
blood within roughly 105 minutes (1).
This same lab group also recently published a capsaicin study looking at its
effects on 1500m running time trial performance (3). Again, compared to placebo, 12mg capsaicin resulted in small but
statistically significant improvements in
performance (371.6 ± 40.8 seconds versus 376.7 ± 39 seconds) and reductions
in perceived exertion (18.0 ± 1.9 versus
18.8 ± 1.3 units). To my knowledge, the
only other human performance trial on
capsaicin was published by Opheim and
Rankin (4); they found that ingestion
of 3g/day of cayenne pepper (delivering 25.8mg of capsaicin) for seven days
failed to enhance performance or perceived exertion during a repeated sprint
test consisting of 15x30m sprints, with
35 seconds of rest between sprints. Notably, Opheim and Rankin utilized cayenne pepper instead of a concentrated
capsiate powder and observed a marked
increase in gastrointestinal distress. As
Dr. Helms pointed out in his analysis,
it’s quite possible that this gastrointestinal discomfort masked any potential
performance improvements. In the more
recent group of studies by de Freitas
92
Figure 2
Comparison between the placebo and capsaicin condition
A
B
*
1000
14
10
8
6
4
#
600
400
#
200
2
0
*
800
12
Weight lifted (kg)
Maximum number of repetitions
16
1
2
3
4
Sets
0
1
2
3
4
Sets
Data Calculated from De Feitas et al. 2019 (1)
Comparison between the placebo and capsaicin condition on maximal repetition and volume performed in each set of resistance performed subsequently to a high-intensity intermittent exercise
A = maximum number of repetitions in each set, B = weight lifted (kg) in each set, * = greater than placebo condition (p < 0.05), # = greater than set 2, 3, and 4 (p < 0.05)
et al, the concentrated capsiate supplements have not appeared to cause similar issues.
So, at this point, the literature supporting capsaicin as a potential performance-enhancing supplement is growing, but the evidence is not entirely
unanimous. As many MASS readers have
heard before, replicating and reproducing results is a huge part of the scientific
process, and a key factor influencing our
confidence in any evidence-based conclusion. When we see multiple studies
from the same lab group that appear to
replicate their original findings, that’s a
big step in the right direction. When we
see their findings reproduced by other
lab groups, sampling different populations with slightly different methods, we
have even more confidence. This could
be particularly notable for something
like capsaicin; average habitual intake
of spicy foods tends to vary from region
to region, and it’s possible that habitual
intake of capsaicinoids may impact the
tolerability and physiological effects of
capsaicin supplementation (5).
One of the exciting things about capsaicin is that there are very plausible
mechanisms by which capsaicin could
be expected to enhance performance.
Capsaicin binds to a receptor called the
transient receptor potential vanilloid 1.
We try to avoid excessive use of abbreviations in MASS, but I’m going to go
ahead and call it TRPV1. When TRPV1
receptors are activated, two notable consequences are reduced pain perception
and increased release of calcium from
the sarcoplasmic reticulum, which enhances muscle force production (1). I
find this to be quite promising, because
it is strikingly similar to caffeine. While
caffeine has many physiological effects
of varying importance, our current understanding suggests that reduced pain
93
and effort perception dictate much of
the observed performance benefit. In addition, caffeine was previously shown to
enhance electrically stimulated muscular function in paraplegic and tetraplegic patients with no sensory feedback
from the exercising musculature, and
the authors of the study speculated that
enhanced sarcoplasmic reticulum calcium release might have been driving
the effect (6). There’s a lot more work
to be done, but it will be exciting to
see if the performance applications of
capsaicin are even close to as broad as
those of caffeine, which has been shown
to enhance a remarkably wide range
of performance outcomes (7). If future
research shows capsaicin to have performance effects as large and as broad
as caffeine, it could theoretically be an
appealing alternative to caffeine, with a
presumably lower likelihood of inducing
the sleep disturbance and habituation issues. It’s also quite possible that the two
supplements could pair well together,
since they appear to share the same performance-enhancing mechanisms while
utilizing different receptors. However,
we’ll need more research to figure out if
this overlap results in an additive effect
or redundancy.
Another promising feature of capsaicin supplementation is its potential to
impact things beyond short-term performance. For example, nitric oxide
has long been known to impact hypertrophy, and some rodent research by Ito
THE LITERATURE
SUPPORTING CAPSAICIN AS A
POTENTIAL PERFORMANCEENHANCING SUPPLEMENT IS
GROWING, BUT THE EVIDENCE
IS NOT ENTIRELY UNANIMOUS.
et al has suggested that nitric oxide and
its metabolites might directly promote
hypertrophy by binding to TRPV1, increasing intracellular calcium concentrations, and ultimately stimulating the
mTOR pathway (8). They also reported
that capsaicin administration appeared
to promote hypertrophy in the absence
of mechanical loading and attenuated
atrophy during unloading (8). It’s totally uncertain if these findings have relevance to healthy humans lifting weights,
but they’re definitely somewhere between interesting and promising. Capsaicin also has some more direct evidence
supporting its applications for fat loss
and weight management. As reviewed
by Ludy et al (5), several studies have
shown capsaicin and other capsaicin-related compounds (collectively known as
capsaicinoids) to increase resting energy expenditure, but to a magnitude that
would only amount to 50-100 kcal/day
94
EMERGING STUDIES APPEAR
TO SHOW A POSITIVE
ACUTE PERFORMANCE
BENEFIT, AND THERE IS
REASON TO BELIEVE THAT
CAPSAICIN MAY HAVE OTHER
POSITIVE APPLICATIONS.
at most. When it comes to appetite regulation, the capsaicinoid research is fairly
mixed. Nonetheless, there are some isolated studies that report increased satiety, reduced hunger, reduced ad libitum
energy intake, and reduced desire to eat
fatty foods, hot foods, salty foods, and
food in general following capsaicinoid
ingestion (5). Finally, a review by McCarty et al (9) lists a number of health
benefits that have been associated with
capsaicin, with the potential to favorably affect outcomes related to atherosclerosis, diabetic vasculopathy, metabolic syndrome, fatty liver, and many
other conditions. I certainly don’t mean
to imply that capsaicin is the hypertrophy holy grail we’ve been searching for,
or a shortcut to fat loss, or a cure-all for
numerous medical conditions. Rather,
the take-home message is that emerging
studies appear to show a positive acute
performance benefit, and there is reason
to believe that capsaicin may have other positive applications, many of which
have yet to be confirmed.
Having said that, we can’t get too carried away with our enthusiasm just yet.
There are only a few studies reporting
performance improvements following
capsaicinoid supplementation, so more
research will certainly enhance our understanding of exactly how effective
capsaicinoids could be. Furthermore,
we have a lot of work to do before we
can confidently know the exact dose(s)
and source(s) to optimize outcomes
and minimize potential gastrointestinal
symptoms. For now, one or two 12mg
doses of purified capsiate powder seem
to get the job done, so that seems to be
the most advisable approach until further
notice. Whenever possible, I prefer to
get things from food sources rather than
supplement products. When it comes to
capsaicin, that should theoretically be
possible. It is estimated that capsaicinoid content accounts for roughly 1%
of the total weight of capsicum spices
like chili and red pepper; as a result,
high daily intakes are routinely achieved
from food alone in countries that tend to
favor relatively spicy cuisines. For example, doses as low as 12mg have been
shown to acutely enhance performance;
average daily capsaicin intake in Europe
is roughly 1.5mg/day, whereas intakes
in India and Mexico can be in the range
95
APPLICATION AND TAKEAWAYS
The literature is far from conclusive, but this study adds to a very small but growing
collection of studies indicating that capsaicinoid supplementation acutely enhances
resistance training capacity. The key underlying mechanism is probably related
to a reduction in perceived pain and exertion, but increased calcium release from
the sarcoplasmic reticulum might contribute as well. There are justifiable reasons
to believe that capsaicin might also have some modest but positive effects on
hypertrophy and fat loss, but longitudinal research is needed to fully elucidate
capsaicin’s potential. High doses of cayenne pepper have caused gastrointestinal
symptoms, so the limited evidence available points toward ingesting a 12mg dose of
a concentrated capsiate supplement 45 minutes prior to exercise. For long-duration
workouts, you might also consider taking a second dose immediately before the
onset of exercise.
of 25-200mg/day (10). However, it’s
hard to confidently say that a large bolus
of capsaicin-rich food would be advisable before a workout, as Opheim and
Rankin reported very notable gastrointestinal discomfort following 3g doses
of cayenne pepper yielding 25.8mg of
capsaicin (4). If you do try to increase
your capsaicin intake and find the burning sensation in your mouth to be unpleasant, fear not– we’ve got research
for that. A 2019 study (11) found that
whole milk, skim milk, and Kool-Aid
tend to be particularly effective beverages for acutely extinguishing the burn.
Next Steps
This body of literature is just beginning
to take shape, so there is plenty of work
to be done. For starters, it’s important to
see more and more independent labs reproduce these positive effects on lifting
performance, sampling a variety of different populations with different habitual intakes of capsaicinoid-rich foods and
spices. After that, a longitudinal training
study with capsaicinoids would be fantastic. Such a study would clarify whether or not a short-term boost in training
capacity really translates to meaningful
strength and muscle gains over time, but
would also shed some light on capsaicin’s potential effects on hypertrophy
and fat reduction. Finally, it’d be really
convenient if we could obtain the benefits of capsaicinoid supplementation by
using some of the stuff we’ve already
got sitting in our spice rack, but we need
more evidence to determine if ergogenic
capsaicinoid doses can be reliably obtained from less purified capsaicinoid
sources without inducing gastrointestinal symptoms.
96
References
1. de Freitas MC, Cholewa JM, Panissa VLG, Toloi GG, Netto HC, Zanini de Freitas C, et al.
Acute Capsaicin Supplementation Improved Resistance Exercise Performance Performed
After a High-Intensity Intermittent Running in Resistance-Trained Men. J Strength Cond
Res. 2019, ePub ahead of print.
2. Conrado de Freitas M, Cholewa JM, Freire RV, Carmo BA, Bottan J, Bratfich M, et al. Acute
Capsaicin Supplementation Improves Resistance Training Performance in Trained Men. J
Strength Cond Res. 2018 Aug;32(8):2227–32.
3. de Freitas MC, Cholewa JM, Gobbo LA, de Oliveira JVNS, Lira FS, Rossi FE. Acute Capsaicin Supplementation Improves 1,500-m Running Time-Trial Performance and Rate of Perceived Exertion in Physically Active Adults. J Strength Cond Res. 2018 Feb;32(2):572–7.
4. Opheim MN, Rankin JW. Effect of capsaicin supplementation on repeated sprinting performance. J Strength Cond Res. 2012 Feb;26(2):319–26.
5. Ludy M-J, Moore GE, Mattes RD. The Effects of Capsaicin and Capsiate on Energy
Balance: Critical Review and Meta-analyses of Studies in Humans. Chem Senses. 2012
Feb;37(2):103–21.
6. Mohr T, Van Soeren M, Graham TE, Kjaer M. Caffeine ingestion and metabolic responses of
tetraplegic humans during electrical cycling. J Appl Physiol. 1998 Sep;85(3):979–85.
7. Grgic J, Grgic I, Pickering C, Schoenfeld BJ, Bishop DJ, Pedisic Z. Wake up and smell the
coffee: caffeine supplementation and exercise performance-an umbrella review of 21 published meta-analyses. Br J Sports Med. 2019, ePub ahead of print.
8. Ito N, Ruegg UT, Kudo A, Miyagoe-Suzuki Y, Takeda S. Activation of calcium signaling
through Trpv1 by nNOS and peroxynitrite as a key trigger of skeletal muscle hypertrophy.
Nat Med. 2013 Jan;19(1):101–6.
9. McCarty MF, DiNicolantonio JJ, O’Keefe JH. Capsaicin may have important potential for
promoting vascular and metabolic health. Open Heart. 2015 Jun;2(1):e000262.
10. Astrup A, Kristensen M, Gregersen NT, Belza A, Lorenzen JK, Due A, et al. Can bioactive
foods affect obesity? Ann N Y Acad Sci. 2010 Mar;1190:25–41.
11. Nolden AA, Lenart G, Hayes JE. Putting out the fire - Efficacy of common beverages in reducing oral burn from capsaicin. Physiol Behav. 2019 01;208:112557.
97
Study Reviewed: What Makes Long-term Resistance-Trained Individuals So Strong?
A Comparison of Skeletal Muscle Morphology, Architecture, and Joint Mechanics.
Maden-Wilkinson et al. (2019)
Simplified Strength Tests Reveal
the True Importance of Muscle Size
for Force Output
BY G RE G NUC KO LS
In a max squat, there are a lot of moving parts … literally. When we strip
away as much of the skill component as possible to simply measure sheer
muscular force output, we see that trained lifters produce more force than
untrained lifters almost entirely due to the fact that their muscles are larger.
98
KEY POINTS
1. Researchers examined quadriceps contractile force during isometric knee
extensions and sought to explain the factors that make trained lifters stronger than
untrained lifters.
2. While a couple other factors that are related to force output differed between
groups, such as quadriceps specific tension and patella tendon moment, the sheer
difference in quadriceps mass was certainly the primary explanatory factor.
3. In more complex movements, skill obviously plays a huge role. However, muscle
size ultimately constrains the sheer amount of force you’re able to produce.
I
have always approached offseason
programming for powerlifting as,
essentially, bodybuilding with a
little heavy work mixed in so the Big 3
don’t get rusty. That came from the understanding that building muscle is the
best way to elevate your strength potential. However, that concept isn’t without pushback. Some coaches and lifters
downplay hypertrophy programming,
instead keeping training heavy and highly specific year-round, with virtually no
pure hypertrophy training. Many roads
lead to Rome, obviously, but I really do
think many lifters are doing themselves
a disservice by not trying to get as muscular as possible, based on the results of
the present study and studies like it.
In the present study (1), 52 untrained
and 16 trained lifters tested their maximal isometric knee extension force. Researchers also measured quadriceps size,
fascicle length, pennation angle, specific tension, and patella tendon moment
arm length. The trained lifters could
produce about 60% more force than the
untrained subjects, which could mostly
be explained by quads that were 41-56%
larger. In fact, after accounting for quadriceps volume, no other variable helped
predict knee extension force, because
the relationship between quadriceps volume and quadriceps force was so strong.
Obviously a squat is more complex than
an isometric knee extension, but I think
this study lends support to the idea that,
at minimum, muscle size is the primary
constraint on the sheer amount of force
you can produce. Whether or not you
can apply that force toward a complex
movement is where skill and technique
come in, but you can’t out-technique a
lack of muscle mass.
Purpose and Hypotheses
Purpose
The purpose of the study was to determine the factors that contribute to the
greater quad strength and muscle vol-
99
Table 1
trained men
Quadriceps muscle size indices, individual constituent muscle volumes and proportional volumes of untrained and long-term resistanceUntrained men
(n=52)
Long-term trained men
(n=16)
Significant
difference?
% Difference
Effect size
1838.2 ± 262.9
2881.9 ± 308.1
yes
56
3.7
Sum of maximal anatomical crosssectional areas from individual
muscles (cm2)
86.2 ± 11.2
135.0 ± 15.0
yes
50
3.3
Quadriceps physiological crosssectional area (cm2)
174.4 ± 19.8
245.7 ± 16.8
yes
41
3.9
167.7 ± 18.8
236.8 ± 15.1
yes
41
4.1
Vastus medialis
441.4 ± 67.8
691.2 ± 87.0
yes
57
3.2
Vastus intermedius
546.9 ± 104
846.4 ± 124.0
yes
55
2.6
Vastus lateralis
609.8 ± 98.4
964.3 ± 90.6
yes
58
3.8
Rectus femoris
240.2 ± 46.7
374.6 ± 72.0
yes
56
2.3
Vastus medialis
24.0 ± 1.7
24.1 ± 1.9
0
0.0
Vastus intermedius
29.7 ± 2.8
29.3 ± 1.6
1
-0.2
Vastus lateralis
33.2 ± 2.6
33.6 ± 2.3
1
0.2
Rectus femoris
13.1 ± 1.8
13.0 ± 1.8
1
-0.1
Muscle and size variable
Quadriceps
Quadriceps volume (cm3)
sectional area (cm2)
Individual muscle volume (cm3)
Proportional muscle volume
(% quadriceps volume)
Data are mean ± SD
* = adjusted P < 0.01
ume in trained lifters compared to untrained individuals.
Hypotheses
The authors hypothesized that:
1. The trained lifters would have more
strength due to greater muscle size
and muscle specific tension.
2. Trained lifters would have greater muscle volume primarily due
to differences in muscle cross-sectional area rather than differences
in fascicle length.
3. There would be evidence of regional hypertrophy in the trained lifters when comparing their quads to
those of the untrained lifters.
Subjects and Methods
Subjects
52 untrained and 16 trained lifters participated in this study. The trained lifters
had been performing systematic, heavy
resistance training for their quads approximately three times per week for
100
Figure 1
Trained (% greater than untrained)
70
60
50
40
30
20
10
Muscle size
at least five years. Trained lifters were
excluded if they used steroids or if they
participated in an endurance sport or a
sport with weight classes (to exclude
people who may want to limit hypertrophy). Thus, the subjects consisted
of eight general strength trainees, six
national-level rugby players, and two
powerlifters and/or bodybuilders (the
wording is vague; if one of the subjects
was a powerlifter, they were presumably
a superheavyweight).
Muscle
architecture
Integrated
morphology
Patella tendon
moment arm
Specific tension
Quadriceps effective
physiological
cross-sectional area
Fascicle length
Pennation angle
Quadriceps physiological
cross-sectional area
Quadriceps anatomical
cross-sectional area
Quadriceps
volume
Maximum voluntary
torque
0
Joint
mechanics
Experimental Design
All of the subjects began by completing a familiarization session to get accustomed to performing isometric maximal
voluntary contractions. This was followed by two strength testing sessions
separated by 7-10 days. The strength
testing sessions consisted of maximum
voluntary isometric knee extension and
knee flexion contractions. During a separate study visit, researchers performed
ultrasound and MRI imaging of the
101
Figure 2
Relationship between torque and quadriceps volume
Maximum voluntary torque (Nm)
500
400
300
All: r=0.904; P<0.01
200
100
0
0
1000
2000
3000
4000
Quadriceps volume (cm3)
subjects’ quads. The imaging was used
to assess quadriceps muscle volume,
cross-sectional area, and fascicle length,
pennation angle, and patella tendon moment arm.
Findings
Maximum voluntary knee extension
strength was 60% greater in the trained
subjects (388 ± 70 vs. 245 ± 43 Newton-meters).
Unsurprisingly, quadriceps size was
also greater in the trained subjects.
Quadriceps volume was 56% greater,
quadriceps anatomical cross-sectional
area was 50% greater, and quadriceps
effective physiological cross-sectional
area was 41% greater. This held true for
all of the individual quadriceps muscles
102
as well, without much deviation between muscles (i.e. total quadriceps volume was 56% greater, and the volume
for each individual head of the quads
was between 54% and 58% greater).
Fascicle lengths and pennation angles were also greater for the trained
subjects, by 11% and 13%, respectively. Patella tendon moment arm was 4%
greater for the trained subjects, but that
may simply be due to height (the trained
subjects were a bit taller, and patella tendon moment arms are longer for taller
people). Specific tension – quadriceps
force divided by effective physiological
cross-sectional area – was 8% greater
for the trained subjects.
Regression analysis suggested that
virtually all of the measured variables
were associated with maximal isometric force, though the correlations were
strongest for measures of muscle size
(r = 0.87-0.9), and weaker for the other variables (r = 0.41-0.61). Adding additional variables into a multiple linear
regression model that already contained
quadriceps volume was unable to significantly improve the ability to predict
isometric knee extension force.
There was no evidence of regional hypertrophy. The proportional size of each
of the quadriceps muscles and the overall shape of all four muscles along their
entire length was similar in both groups.
ALL MEASURES OF MUSCLE
SIZE WERE VERY STRONGLY
CORRELATED WITH KNEE
EXTENSION STRENGTH;
ALL OTHER FACTORS WERE
MUCH MORE WEAKLY
CORRELATED WITH KNEE
EXTENSION STRENGTH.
Interpretation
As one slight complaint about the
present study (1), I’m not crazy about
the language the authors use to describe
their research aims. They claim that they
wanted to “determine the factors that
contribute to the greater quad strength
and muscle volume in trained lifters
compared to untrained individuals.”
They use similar language throughout
the study. They’d need a well-controlled
longitudinal study to make determinations. For such research questions,
cross-sectional research is merely suggestive. Now, I do think the suggestions
that can be derived from this study are
pretty freaking strong suggestions, but
the authors’ wording is a little too strong
103
YOU CAN’T NECESSARILY CLAIM
THAT MUSCLE GROWTH CAUSES
STRENGTH GAINS, SINCE
MUSCLE GROWTH IS NEITHER
NECESSARY NOR SUFFICIENT
FOR STRENGTH GAINS TO
OCCUR. HOWEVER, YOU SIMPLY
CAN’T PRODUCE MORE FORCE
THAN YOUR CONTRACTILE
TISSUE ALLOWS FOR.
and authoritative for my liking.
This study helps to illustrate an important point that I think people miss when
discussing the factors they should focus
on for strength development: muscle
growth is likely the primary constraint
on strength development. That’s not always perfectly obvious with compound
exercises (you may increase your max
without adding muscle, or add muscle
without immediately increasing your
max), but it becomes crystal clear when
we strip away layers of confounders and
simply examine the amount of force
muscles can produce during extremely
simple tasks.
In most circumstances, I prefer studies
that use free weight, compound exercises. In this instance, however, single-joint
isometric contractions were preferable.
Single-joint isometric contractions require virtually no skill, and voluntary
activation of motor units isn’t a problem for most healthy, young people (2).
Thus, we can truly see the amount of
force a muscle is capable of producing
and the factors contributing to that muscles’ ability to exert force. If squats were
used to assess strength instead, skill becomes a much larger factor. There’s no
way to know that each of the muscles
involved in the lift is actually producing
as much force as it’s capable of.
Overall, it appears that muscle size was
by far the most important factor contributing to quad strength. The trained lifters’ quads were 60% stronger than the
untrained lifters’, and their quads were
also 41-56% larger (depending on the
measure of size you look at). The only
other factors assessed that would directly contribute to strength are patella
tendon moment arm length and specific tension; however, those factors were
similar enough between groups (differing by 4% and 8%, respectively) that
they simply couldn’t be the primary
driving factors. Mathematically, knee
extension torque is equal to effective
physiological cross-sectional area of the
quads, multiplied by quadriceps specific
tension, multiplied by patella tendon moment arm length. It’s pretty clear which
104
of those factors was primarily responsible for the 60% difference in strength.
Furthermore, all measures of muscle
size were very strongly correlated with
knee extension strength; all other factors
were much more weakly correlated with
knee extension strength.
I want to reiterate the verbiage I used
previously: muscle growth is the primary constraint on strength development.
You can’t necessarily claim that muscle
growth causes strength gains, since muscle growth is neither necessary nor sufficient for strength gains to occur (at least
in the compound exercises most MASS
readers care about). In other words, you
can get stronger without adding muscle,
and you can add muscle without being
able to immediately set a new personal
record in the squat or bench press. However, you simply can’t produce more
force than your contractile tissue allows
for. The amount of muscle mass you
have dictates the limits of your ability to
produce force. Improving skill and honing technique can’t allow you to produce
more force than your contractile tissue
allows for. To maximize your strength
gains, you also need to maximize your
muscle growth.
One thing worth mentioning, however,
is the huge role that skill plays in strength
development. The trained lifters’ quads
were ~60% stronger than the untrained
lifters’. Squat 1RM strength wasn’t assessed in this study, but I’m almost positive that the trained lifters would have
WHEN COMPARING YOURSELF
TO AN UNTRAINED LIFTER,
DIFFERENCES IN SKILL PROBABLY
DO MATTER CONSIDERABLY
MORE THAN DIFFERENCES IN
MUSCLE SIZE. HOWEVER, WHEN
COMPARING YOURSELF AGAINST
OTHER SERIOUS LIFTERS –
WHO ARE PRESUMABLY ALSO
QUITE SKILLED – MUSCLE
SIZE BECOMES THE PRIMARY
DIFFERENTIATING FACTOR
AGAIN, SINCE ALL COMPETITORS
SHOULD BE QUITE SKILLED.
squatted way more than 60% more than
the untrained lifters. That discrepancy
would be primarily due to technique,
coordination, and skill. I think that’s
one of the reasons why skill and technique are prioritized by many strength
athletes, sometimes at the expense of
hypertrophy training. If you can squat
twice as much as someone else, but your
quads are only actually capable of producing 50% more force, it seems like
skill and technique are three times as
105
APPLICATION AND TAKEAWAYS
1. Muscle mass is the primary constraint on the amount of force you can produce.
2. If you want to maximize your strength gains, you also need to maximize your
muscularity.
important as muscle mass. And that may
be true, from one perspective. However, from another perspective, neglecting
hypertrophy work can become extremely limiting. When comparing yourself to
an untrained lifter, differences in skill
probably do matter considerably more
than differences in muscle size. However, when comparing yourself against other serious lifters – who are presumably
also quite skilled – muscle size becomes
the primary differentiating factor again,
since all competitors should be quite
skilled. In fact, research on elite powerlifters has found that various measures
of muscularity (lean body mass, LBM
per cm, and muscle thicknesses) could
almost perfectly predict strength in the
squat, bench, and deadlift (3). Similar
research has found a similar relationship
in junior weightlifters (4).
One random thing that jumped out
to me in this study was the difference
in muscle specific tension. The difference between groups was only about
8%. Previous research has shown that
quadriceps specific tension can actually increase by more than 8% after just
10 weeks of training (5). Thus, training
does improve your muscles’ ability to
exert force independent of muscle size,
but that adaptation may run its course
within your first few months of lifting.
Experienced lifters may not continue to
improve specific tension with continued
training.
You may still have some questions
about the relationship between muscle
growth and strength development. For
example, “I know a guy/gal who doesn’t
appear to have that much muscle, who’s
out-lifting people who are way more
muscular than him/her. How do you explain that?” That’s the biggest source
of pushback I get when shilling for Big
Hypertrophy™. The long answer to
that question (and probably any others
you may have about the relationship
between muscle growth and strength)
is this article. The short answer to that
question is that people are just different.
They may have different training histories, different muscle moment arms, different muscle specific tensions (which
differ pretty dramatically between individuals), etc. The fact that less muscular
people sometimes out-lift (or can simply produce more force, even in simple
tasks) more muscular people doesn’t
mean that the more muscular people ar-
106
en’t still benefiting from having more
muscle, or that the less muscular people
wouldn’t be even stronger if they added
more muscle to their frames.
Finally, it’s worth addressing the lack
of evidence for regional hypertrophy
in this study. I don’t actually think this
study shakes up the data on the topic very
much. We already know that you can get
well-rounded growth of the quads (rather than growth concentrated in just one
or two heads of the quads) by performing a variety of exercises instead of just
one (6). I take the lack of clear regional hypertrophy in this study as evidence
that the subjects simply used sufficient
exercise variety in their training, rather
than evidence that regional hypertrophy
can’t occur.
their muscles are actually being asked to
exert maximal force), while a high relative muscular effort would indicate high
skill. You could also add a longitudinal
component onto the study to examine
how relative muscular effort changes
with increasing training experience.
Next Steps
I think it would be neat to expand
this study a bit by recording quadriceps
force at various different joint angles
and also having subjects perform a max
squat. With that data, you could calculate relative muscular effort in the squat
– essentially a ratio between the knee
moments observed during a squat, and
the maximal knee extension moments
the quads are able to produce at each
corresponding joint angle (7). I think
relative muscular effort would help us
quantify skill in the lift. A low observed
relative muscular effort would indicate
poor skill (they’re failing the lift before
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References
1. Maden-Wilkinson TM, Balshaw TG, Massey G, Folland JP. What makes long-term resistance-trained individuals so strong? A comparison of skeletal muscle morphology, architecture, and joint mechanics. J Appl Physiol (1985). 2019 Dec 24.
2. Noorkõiv M, Nosaka K, Blazevich AJ. Neuromuscular adaptations associated with knee
joint angle-specific force change. Med Sci Sports Exerc. 2014 Aug;46(8):1525-37.
3. Brechue WF, Abe T. The role of FFM accumulation and skeletal muscle architecture in powerlifting performance. Eur J Appl Physiol. 2002 Feb;86(4):327-36.
4. Siahkouhian M, Hedayatneja M. Correlations of anthropometric and body composition variables with the performance of young elite weightlifters. Journal of Human Kinetics. 2010;
25(3): 125-31.
5. Erskine RM, Jones DA, Williams AG, Stewart CE, Degens H. Inter-individual variability
in the adaptation of human muscle specific tension to progressive resistance training. Eur J
Appl Physiol. 2010 Dec;110(6):1117-25.
6. Fonseca RM, Roschel H, Tricoli V, de Souza EO, Wilson JM, Laurentino GC, Aihara AY, de
Souza Leão AR, Ugrinowitsch C. Changes in exercises are more effective than in loading
schemes to improve muscle strength. J Strength Cond Res. 2014 Nov;28(11):3085-92.
7. Bryanton MA, Kennedy MD, Carey JP, Chiu LZ. Effect of squat depth and barbell load on
relative muscular effort in squatting. J Strength Cond Res. 2012 Oct;26(10):2820-8.
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VIDEO: Setting Up
Full-Body Training
BY MIC HAE L C . ZO URD O S
It can be challenging to set up a full-body training program that effectively
manages fatigue. This video shows you how to do that, while examining the unique
ability of high frequency full body training weeks to allow for volume cycling
between upper and lower body muscle groups.
Click to watch Michael's presentation.
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References
1. Agonist-Antagonist Paired Sets: The Sensible Superset. Volume 1 Issue 8.
2. Details Matter When Setting up A Full-Body Training Program. Volume 2 Issue 5.
3. VIDEO: Program Troubleshooting. Volume 2 Issue 7.
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VIDEO: Post-Season
Nutrition Strategies, Part 2
BY E RI C HE LMS
In part 1 of this series, we modeled “metabolic adaptation” during contest preparation
to explain what occurs and why. Also, we covered how “reverse dieting” impacts
outcomes. In part 2, we dive into the scant but relevant research pertaining to reverse
and “recovery” diets to discuss the aspects which should be considered from a broad,
biopsychosocial perspective.
Click to watch Eric's presentation.
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Relevant MASS Videos and Articles
1. How Are Female Physique Competitors Impacted By Contest Preparation?. Volume 1 Issue
2.
2. Contest Prep Recovery in Male and Female Physique Competitors. Volume 1 Issue 3.
3. Dealing with Metabolic Adaptations to Weight Loss. Volume 2 Issue 5.
4. Energy Availability in Strength and Power Athletes. Volume 2 Issue 11.
5. Ramifications of Weight Manipulation in Female Physique Athletes. Volume 3 Issue 8.
6. VIDEO: The Nuts and Bolts of Diet Periodization, Part 2. Volume 2, Issue 12.
7. VIDEO: Global Contest Prep Fatigue Management, Part 1. Volume 3, Issue 5.
References
8. Longstrom, J., Colenso-Semple, L, Trexler, E.T, Waddell, B, Ford, S, Ford, Callahan, K,
Nguyen, T, Campbell, B. Post-Competition Weight Gain in Physique Athletes: A Case Series
Approach. In Proceedings of the 16th International Society of Sports Nutrition (ISSN) Conference and Expo, Las Vegas, NV, USA, 13–15 June 2019.
9. Halliday T, Loenneke J, Davy B. Dietary intake, body composition, and menstrual cycle
changes during competition preparation and recovery in a drug-free figure competitor: a case
study. Nutrients. 2016;8(11):740.
10. Helms ER, Prnjak K, Linardon J. Towards a Sustainable Nutrition Paradigm in Physique
Sport: A Narrative Review. Sports. 2019 Jul;7(7).
11. Trexler ET, Hirsch KR, Campbell BI, Smith-Ryan AE. Physiological Changes Following
Competition in Male and Female Physique Athletes: A Pilot Study. International journal of
sport nutrition and exercise metabolism. 2017 Oct;27(5):458.
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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.
1. Nigro and Bartolomei. A comparison between the squat and deadlift for lower body strength
and power training
2. Tinsley et al. A Purported Detoxification Supplement Does Not Improve Body Composition, Waist Circumference, Blood Markers, or Gastrointestinal Symptoms in Healthy Adult
Females
3. Vigar et al. A Systematic Review of Organic Versus Conventional Food Consumption: Is
There a Measurable Benefit on Human Health?
4. Ribeiro et al. Acute Effects of Different Training Loads on Affective Responses in Resistance-trained Men
5. Feriche et al. Altitude-induced effects on muscular metabolic stress and hypertrophy-related factors after a resistance training session
6. Keller et al. Are There Sex-Specific Neuromuscular or Force Responses to Fatiguing Isometric Muscle Actions Anchored to a High Perceptual Intensity?
7. Polito et al. Caffeine and resistance exercise: the effects of two caffeine doses and the influence of individual perception of caffeine
8. Nicholls et al. Cheater, cheater, pumpkin eater: the Dark Triad, attitudes towards doping,
and cheating behaviour among athletes
9. Tillaar. Comparison of Kinematics and Muscle Activation between Push-up and Bench
Press
10. Padilha et al. Could inter-set stretching increase acute neuromuscular and metabolic responses during resistance exercise?
11. Whitehead et al. Disordered eating behaviours in female physique athletes.
12. McFarlin et al. Does Acute Improvement in Muscle Recovery with Curcumin Supplementation Translate to Long-Term Training?
13. Colpitts et al. Does lean body mass equal health despite body mass index?
14. Wessner et al. Effects of acute resistance exercise on proteolytic and myogenic markers in
skeletal muscles of former weightlifters and age-matched sedentary controls
15. Chan et al. Effects of Attentional Focus and Dual-tasking on Conventional Deadlift Performance in Experienced Lifters
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16. Rindom et al. Estimation of p70S6K Thr389 and 4E-BP1 Thr37/46 phosphorylation support
dependency of tension per se in a dose-response relationship for downstream mTORC1 signalling
17. Axsom et al. Impact of parental exercise on epigenetic modifications inherited by offspring:
A systematic review
18. Brice et al. Impact of performing heavy-loaded barbell back squats to volitional failure on
lower limb and lumbo-pelvis mechanics in skilled lifters
19. Centala et al. Listening to Fast-Tempo Music Delays the Onset of Neuromuscular Fatigue
20. Gómez-Carmona et al. Lower-limb Dynamics of Muscle Oxygen Saturation During the
Back-squat Exercise: Effects of Training Load and Effort Level
21. Krzysztofik et al. Maximizing Muscle Hypertrophy: A Systematic Review of Advanced Resistance Training Techniques and Methods.
22. Fouré et al. Muscle alterations induced by electrostimulation are lower at short quadriceps
femoris length
23. Grandou et al. Overtraining in Resistance Exercise: An Exploratory Systematic Review and
Methodological Appraisal of the Literature
24. Wikander et al. Prevalence of urinary incontinence in women powerlifters: a pilot study.
25. Hudson et al. Protein Intake Greater than the RDA Differentially Influences Whole-Body
Lean Mass Responses to Purposeful Catabolic and Anabolic Stressors: A Systematic Review
and Meta-analysis.
26. Lim et al. Resistance Exercise–induced Changes in Muscle Phenotype Are Load Dependent
27. Nakamura et al. The effect of low-intensity resistance training after heat stress on muscle size
and strength of triceps brachii: a randomized controlled trial.
28. Hagstrom et al. The Effect of Resistance Training in Women on Dynamic Strength and Muscular Hypertrophy: A Systematic Review with Meta-analysis
29. Thompson et al. The Effectiveness of Two Methods of Prescribing Load on Maximal Strength
Development: A Systematic Review
30. Androulakis-Korakakis et al. The Minimum Effective Training Dose Required to Increase
1RM Strength in Resistance-Trained Men: A Systematic Review and Meta-Analysis
31. Schoenfeld et al. To Flex or Rest: Does Adding No-Load Isometric Actions to the Inter-Set
Rest Period in Resistance Training Enhance Muscular Adaptations? A Randomized-Controlled Trial
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Thanks for
reading MASS.
The next issue will be released to
subscribers on March 1, 2020.
Graphics by Kat Whitfield, and layout design by Lyndsey Nuckols.
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