1. This study compared two equated volume programs but with dierent training frequencies for performance and body composition. The study compared a frequency of two versus four times per week for some muscle groups, and two versus one time per week for other muscle groups.
2. The main results showed no dierences between groups for any performance or body composition measure. When volume is equated and there is a frequency of at least two times per week, additional frequency may not matter too much.
3. Importantly, both groups in this study met the already-established recommendations for weekly volume, which likely explains the lack of dierences between groups.
ait a second. First, “More Volume is Not Always Better” and now
“More Frequency is not Always Better”? I know, we are calling everything into question, but that’s a good thing, and that’s how we move forward. Despite the title of this article, meta-analyses have concluded that a frequency of at least two times per muscle group per week is better than once per week for hypertrophy (2) and strength (3). So how did this study show that more frequency wasn’t better?
Tis study had two groups which were volume-equated and trained for six weeks:
1) High frequency (n=9), which per-formed four total sessions per week with a frequency of twice per week on a mus-cle group but with a low per-session vol-ume, and 2) Low frequency (n=9), which performed two total sessions per week with a frequency of once per week on a muscle group, but with a high per-session volume. For clarity, volume was equated between groups and across all six weeks.
Per-session volume was just higher in the low frequency group. Te main variables assessed from pre- to post-study and between groups were: squat and bench one-repetition maximum (1RM); quad-riceps, biceps, and deltoid hypertrophy;
body composition; and bench press pow-er (powpow-er output at 50% of 1RM). Tpow-ere were no statistically significant differenc-es between groups for any measure, and both groups experienced hypertrophy and improved 1RM strength and power output. However, there were some im-portant meaningful differences. Specif-ically, between-group effect sizes (ES) revealed a large effect (0.89) in favor of low frequency for bench press 1RM and a moderate effect (0.53) also in favor of low frequency for biceps hypertrophy. Also of note was a small effect (0.45) again in fa- vor of low frequency for improvement in fat-free mass. At first glance, these ES re-sults are a little jarring in that they point to a huge win for lower frequency.
How- W
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ever, there are some statistical questions and methodology considerations, which I believe explain, and – in some ways – call into question the authors’ conclusions.
So, let’s not count it as a point in the col-umn of low frequency yet. Let’s critically analyze everything in play here.
Purpose and Research Questions
Purpose
Te purpose of this study was to ex-amine the effects of equated volume but different weekly training frequencies on
maximal strength, hypertrophy, power, and body composition over six weeks in trained males.
Research Question
Does a frequency of twice per week on a muscle group (four total sessions) produce greater performance and better body composition outcomes than train-ing a muscle group once per week (two total sessions)? Quick Note: Although the actual paper pitches this study as a one ver-sus two time per week frequency for each muscle group, it’s more like a two versus four time per week, as I’ll explicitly point
out in a bit.
Table 1
Subject CharacteristicsHigh Frequency
Low Frequency
21 ± 3 180.4 ± 4.8 76.63 ± 14.72
Age (years)
Subjects Height (cm)
Body Mass (kg)
3.0 ± 0.5
28 ± 8 178.6 ± 6.7 79.38 ± 14.22 2.9 ± 0.4
Training Age (yrs.)
Data are Mean ± SD
Subjects characteristics from Yue et al. 2017 (1)
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Hypotheses
Although a hypothesis was not ex-pressly stated, the introduction indicates that the authors expected the high fquency group to experience better re-sults than the low frequency group.
Subjects and Methods
Subjects
Tis study had 18 men who had trained 2-3 times per week using a whole-body routine for 2-5 years prior to the start of the study; however, there were no baseline strength criteria – just a training experience criteria. Te de-scriptive statistics for each group can be seen in able 1.
Study Protocol
Tis study spanned a total of seven weeks. Te first week, subjects came to the lab three times for familiarization sessions to ensure proper exercise tech-nique. Te next six weeks served as the training program. In short, both the high frequency group (n=9) and the low frequency group (n=9) trained for six weeks with pre- and post-study mea-surements for performance and body composition. Strength was measured via 1RM squat and bench, hypertrophy was assessed via muscle thickness and limb circumference, power was assessed by testing power output ( Watts) at 50% of bench 1RM, and body composition was
estimated via a BOD POD. Te high frequency group trained Monday, ues-day, Tursues-day, and Friday. Monday’s and Tursday’s sessions (Routine 1) di-rectly targeted the chest, shoulders, and biceps. uesday’s and Friday’s sessions (Routine 2) directly targeted the legs, back, and triceps. Te low frequency group trained on only Mondays (Rou-tine 1) and Tursdays (Rou(Rou-tine 2). Te high frequency group performed two sets per exercise, and the low frequency group performed four sets per exercise.
All sets were performed at approxi-mately 75% of 1RM and were taken ei-ther to failure or to 12 reps, whichever was reached first. If 12 reps were per-formed and subjects thought they could do additional reps, then 2.5kg was add-ed to the load for the next set. able 2 shows the specific exercises completed for both groups.
Importantly, this study is billed as a comparison of training a muscle group two times versus one time per week (so that’s how our purpose and research ques-tions were written); however, after review-ing able 2, you can see that’s not really the case. Most muscle groups were trained more than that, at least indirectly. Tere-fore, I think it’s more accurate to say that this study compared a training frequency of two versus four times per week on a mus-cle group. o illustrate this, I created able 3, which breaks down how many times per week each muscle group was directly trained and indirectly trained to provide
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the truest comparison of weekly frequency.
It’s important to do this, because a recent meta-analysis (2) – which recommends a frequency of 2-3 times per week for mus-cle growth – includes indirectly training a muscle group (i.e. rows count indirectly for biceps) in that recommendation.
Findings
Tere were no statistically significant differences between groups, in terms of p-values, for any outcome measure.
However, there were some instances where an outcome measure statistically Table 2 Training Protocol, Training Variables, and Outcome Measures
Routine 1 Routine 2
Bench Press
DB Fly
Chest Press
Bar Curl
Seated DB Curl
Bench Over Row
DB Lateral Raise
Military Press
Bar Front Raise
Lat Pulldown
DB Rear Delt
Bar Pullover
Bar Triceps Ext.
Close Grip Bench
Triceps Pushdowns
Squat
Deadlift
Leg Curl
This table shows the specific exercises completed for each group.
Both “routines” were performed twice per week in the high frequen-cy group and once per week in the low frequenfrequen-cy group.
DB = Dumbbell, 1RM = One-Repetition Maximum
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improved from pre- to post-study in the low frequency group but not in the high frequency group. Tose measures were:
fat mass, fat-free mass, arm circumfer-ence, and biceps hypertrophy. Further, there were meaningful effect sizes in fa- vor of the low frequency group for the following variables: body mass (loss), fat mass, fat-free mass, biceps hypertrophy, 1RM bench, 1RM squat, and bench press power. In short, all of the mean-ingful differences were in favor of the low frequency group; therefore, these re-sults suggest a possible benefit for low-er frequency training for body compo-sition, strength, and hypertrophy. able 4 displays pre- to post-study means, the mean change, the comparison p-value, and the between-group ES for all vari-ables.
Interpretation
Although able 3 shows some effect sizes in favor of the low frequency group, I think it’s most important to point out that there were no significant differenc-es between groups in terms of p-val-ues. Further, when you look closely at able 3, the effect sizes in favor of low frequency become less convincing upon critical analysis. For example, there is what is considered a large ES (0.89) in favor of low frequency for 1RM bench press. However, there is a mean change of 11kg for bench press in both groups.
Te standard deviation is much tighter for the low frequency group, which may account for the ES, but the large standard deviation in the high frequency group at post-test (SD=30) also means the great-est individual change may have occurred
Table 3 Breakdown of Both Direct and Indirect Training Frequencies Per Muscle Group
Chest
Bench Press, Chest Press, DB Fly, Close Grip Bench Press
Bar Curl, Seated DB Curl
Lat Pulldown, Bent Over Row, Bar Pullover, Deadlift
Military Press, Bar Front Raise, DB Rear Delt
Bar Triceps Ext, Close Grip Bench, Triceps Pushdowns
Squat, Deadlift, Leg Curl
Bench Press, Chest Press, DB Fly, Close Grip Bench Press
Bar Curl, Seated DB Curl, Bent Over Row, Bar Pullover
Lat Pulldown, Bent Over Row, Bar Pullover, Deadlift, DB Rear
Delt
Military Press, Bar Front Raise, DB Rear Delt, Close Grip Bench
Bar Triceps Ext, Close Grip Bench, Triceps Pushdowns,
Bench Press
Squat, Deadlift, Leg Curl
2 / 4 Trained LVHF / HVLF
What’s Included for
in that group. Ultimately, with only nine subjects in each group and similar mean changes, I think these effect sizes should be interpreted cautiously.
Continuing with the ES discussion, the effect sizes in this study were calculated in an unorthodox manner. Te authors calculated partial eta squared effect sizes from their main statistical model, which
was an analysis of covariance (ANCO-VA), and then converted the effect sizes to a between-group Cohen’s d (the lat-ter is what you see in our inlat-terpreting research document). When you look at the mean changes (i.e. bench press 1RM mean change is identical between groups) in able 3, it seems impossible that the meaningful effects in favor of
This table shows the pre and post-study means + SD, the mean change + SD, the between group p-values, and between group effect sizes (ES) for every outcome measure.
*, Significant change from pre-study; #, Effect size is >0.20 indicating a t least a small effect in favor of HVLF; LVHF, Low Volume High Frequency; HVLF, High Volume Low Frequency; 1RM, One-Repetition Maximum
Table 4Pre to Post-Study Changes and Between Group Effect Sizes for All Variables
77.2± 16.26 0.61± 14.22 79.4± 14.22 79.3± 13.3 -0.06± 2.18 0.054 1.08
Vastus Medialis Thickness (mm)
Elbow Flexors Thickness (mm)
Ant. Deltoids Thickness (mm)
1RM Bench Press (kg)
1 RM Bench Press (kg body mass-1)
1RM Squat (kg)
1 RM Squat (kg body mass-1)
Bench Press Power (watts) at 50% 1RM
Bench Press Power (watts body mass-1)
Pre Post Changes p-value ES
LVHF(n=9) HVLF(n=9) GroupComparisons
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low frequency would show up as such if a Cohen’s d was calculated directly. Tis does not mean that the effect sizes are invalid, nor does it mean that the au-thors were wrong in their reporting, but it does mean that it’s an unorthodox ap-proach. So, when compiling everything in play – lack of p-value differences be-tween groups, similar mean changes, a low sample size, and unorthodox ES calculations – I think it’s prudent to again stress a cautious interpretation of the effect sizes and important to keep in mind that there was no statistical differ-ence between groups.
Now that the stats discussion is out of the way, let’s break down the methodolo-gy a little more. As previously stated, this study is billed as a two versus four total session frequency study and a one versus two times per week muscle group study;
however, as you can see in able 3, this isn’t really the case. All muscle groups (except for legs) were trained directly or indirectly at least twice per week, which means it was a two versus four time per week per muscle group study. What do we currently know about training frequency for hypertrophy and strength? Well, the aforementioned meta-analysis demon-strates that a two time per week frequen-cy promotes greater hypertrophy than a one time per week frequency (2). Previous data also have shown that hypertrophy and strength adaptations are similar be-tween groups when volume is equated (4).
Further, when accounting for all indirect
training in the present study, all muscle groups met the 10+ sets per week recom-mendation which we gave previously in MASS. When all of these factors are tak-en together: both groups in this study had a frequency of >1 time per week, volume was equated between groups, both groups performed 10+ sets per muscle group, and there was no statistical difference between groups. So, although the abstract of the paper suggests better results for the low frequency group for some measures, I am less convinced, and based upon the design, I don’t find the lack of differences surpris-ing. So, even though able 3 shows effect sizes in favor of low frequency for some measures, take another look at how sim-ilar the mean changes are; can we really say with confidence that the low frequen-cy protocol produced superior results? I can’t say that with confidence. However, despite my lack of confidence that those effect sizes do exist, I could be wrong.
With that in mind, let’s now indulge the possibility that there may be a difference in some of these measures and speculate as to why.
If we argue for a second that a mean-ingful difference is present, I would pro-pose three possible reasons: 1) Te high frequency group was under-recovered throughout, 2) Te higher frequency was too much for the relatively low training status, and 3) Te possibility of greater metabolic byproduct accumulation in the low frequency group.
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1) Te high frequency group was un-der-recovered
In this study, all sets were taken to fail-ure, and failure training causes greater fa-tigue than non-failure training for 48-72 hours (More in Eric’s recent articles) (5).
While it is true that the high frequency group did less volume per session than the low frequency group in the present study (1), the high frequency group trained two days in a row at least once per week. Also, we know from able 3 that the subjects in the high frequency group trained most muscle groups on back-to-back days (at least indirectly); therefore, training to fail-ure could have placed the subjects in the high frequency group in a high state of fatigue on their second consecutive train-ing day, compromistrain-ing recoverability and subsequent adaptation.
2) raining Status
In a way, this goes hand-in-hand with the under-recovered hypothesis. Both groups in this study had a starting 1RM bench of <80kg, making them relative novices (check out Figure 1 here) at this exercise. Terefore, training to failure four times per week in the high frequency group may have simply been too much.
Also, even though volume was equated in terms of working sets (able 3), the high frequency group had to warm-up each day. Since the working sets were at 75%, that means they likely had some warm-up sets from 60-70% of 1RM. For someone with a relatively low training status, that
could conceivably count as added volume.
Tus, this could be a case of simply too much frequency or volume for the high frequency group. Finally, even though we know that a frequency of two times per week produces larger strength gains than once per week, we can’t conclude that three is better than two (3). We shouldn’t expect four times to have an added bene-fit in a population not far past the novice lifting phase.
3) Possibility of greater metabolic by- products
Although metabolite build-up may not play a huge role in hypertrophy (6), it may play some role (7). In this study, the low frequency group did more volume per ses-sion, so it’s possible that the low frequency group had a greater metabolite build-up, which could possibly account for the
ef-fect sizes in its favor.
Before we present some next steps, let’s have some last words to clarify our inter-pretation. Te results seem fairly straight-forward to me: this study had a low sample size and compared different frequencies with equated volume and found no dif-ferences between groups for any outcome measure. However, despite the unortho-dox ES calculation, we cannot discount the possibility of a meaningful difference, so we presented some theories as to why these differences may have occurred. Ul-timately, I wouldn’t take this as a win for low frequency. I would take this as anoth-er point in the column of equated
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ume leading to similar training outcomes.
Finally, if you do choose to take it as a win for lower frequency, remember that the training frequency for most muscle groups was actually twice per week, which is in line with previous recommendations.
Next Steps
We first need clarify whether a frequen-cy of three times per week is better than two times per week for hypertrophy and strength. I theorize that in trained lifters, three times per week may be better be-cause it allows for more volume and also allows that volume to be distributed in a way that makes it is easier to achieve high intensity work. I would like to see this study carried out in a more highly trained population and also with muscle groups not being indirectly trained on days they aren’t directly trained. Tis could be done with a training setup of training legs, back, and biceps together and chest, shoulders, and triceps together.
APPLICATION AND TAKEAWAYS
1. When equating for training volume, training frequency doesn’t seem to be a huge variable inuencing adaptations as long as a frequency of at least two times per week is met and muscle group volume is 10+ sets for the week.
2. We cannot yet say if greater than two times per week frequency is necessary to maximize adaptations in highly trained lifters, but if it is, it should likely include increased volume.
3. When counting sets per week on a muscle group, it is important to count when a muscle group is both directly and indirectly trained.
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References
1. Yue, F, Karsten, B, Larumbe-Zabala, Seijo, M, Naclerio, F. Comparison of two equated training weekly volume routines using different frequencies on body composition and performance in trained
males. Applied Physiology, Nutrition, and Metabolism. 2017,ja.
2. Schoenfeld BJ, Ogborn D, Krieger JW.Effects of resistance training frequency on measures of muscle hypertrophy: a systematic review and meta-analysis. Sports Medicine. 2016 Nov 1;46(11):1689-97.
3. Peterson MD, Rhea MR, Alvar BA. Maximizing strength development in athletes: a meta-analysis to determine the dose-response relationship. Te Journal of Strength & Conditioning Research.
2004 May 1;18(2):377-82.
4. Klemp A, Dolan C, Quiles JM, Blanco R, Zoeller RF, Graves BS, Zourdos MC. Volume-equated
4. Klemp A, Dolan C, Quiles JM, Blanco R, Zoeller RF, Graves BS, Zourdos MC. Volume-equated