Hypertrophy, Strength Training
July 25, 2016
The question as to how much strength training volume is needed to maximize muscular gains has been an ongoing source of debate, both in scientific circles as well as the realm of social media. Some claim that a very low volume approach is all that’s required while others subscribe to the belief that marathon training sessions are an absolute necessity.
Who’s right? Well…
Back in 2010, my colleague James Krieger carried out a meta-analysis to provide evidence-based clarity on the topic. In case you’re not aware, a meta-analysis pools data from all relevant studies on a given subject to provide greater statistical power and thus enhance the ability to draw practical inferences from the literature. In short, the analysis showed that performance of multiple sets was associated with a 40% greater hypertrophy-related effect size (a statistical measure of the meaningfulness of results) compared to single-set training.
While this paper provided good evidence in support of higher training volumes, there were some issues with the analysis. For one, James only looked at sets per muscle per workout; a potentially more important marker in determining the hypertrophic response is the weekly volume per muscle group. Moreover, only 8 studies qualified for inclusion in James’ analysis at the time, and only 3 of these studies used direct site-specific measures of muscle growth (i.e. MRI, ultrasound, etc).
Since publication of James’ meta-analysis, a number of additional studies have been published in the peer-reviewed literature. Given this info and in an attempt to resolve previous issues, James and I decided it was appropriate to carry out a follow-up meta-analysis that encompassed all the evidence to date. We recruited our colleague Dan Ogborn to collaborate on the project, and centered our focus on the effects of weekly sets per muscle group on changes in muscle mass. I’m happy to report the paper was recently published in the Journal of Sport Sciences.
Here’s the lowdown:
What We Did
A literature search was conducted to locate all studies that directly compared measures of hypertrophy between higher versus lower resistance training volumes with all other variables equated between conditions. Only human studies with healthy subjects that had a minimum duration of six weeks were considered for inclusion.
What We Found
A total of 15 studies were identified that met inclusion criteria. We ran multiple comparisons to assess the topic from different perspectives. First we evaluated the effects of volume within each study and found that higher volumes were associated with a 3.9% greater average increase compared to lower volumes; the findings were statistically significant (i.e. high probability that they weren’t due to chance alone). As shown in the accompanying forest plot, only 1 of the 15 studies showed a favorable effect for lower volume training, emphasizing the high probability that greater volumes produce greater increases in muscle growth.
We next looked at the effects of volume on a two-level categorical basis, splitting the data into performing less than 9 sets versus 9 sets or more. In this model, the lower volume condition was associated with a gain of 5.8% while the higher volume condition produced a gain of 8.2%. Although the results did not reach statistical significance in this model, the probability of an effect was nevertheless very high (p = 0.076).
Finally, we employed a three-level categorical analysis whereby volume was stratified into less than 5 weekly sets per muscle, 5 to 9 weekly sets per muscle, and 10+ sets per muscle. Here we found a graded dose response whereby gains in muscle progressively increased across each category from 5.4% to 6.6% to 9.8%, respectively. As with the two-level model, results did not quite reach significance, but a high level of confidence can be inferred that results were not due to chance alone (p = 0.074).
What are the Practical Implications
There are several important take-aways from our meta-analysis. First off, a low volume approach can build appreciable muscle. Performing less than 5 weekly sets per muscle produced an average hypertrophic gain of 5.4%. Not too shabby. So if you are time-pressed and not concerned about achieving the upper limits of your muscular potential, it should be heartening to know that you can build an impressive physique without spending a lot of time in the gym.
That said, there is a clear dose-response relationship between volume and hypertrophy. In the three way categorical model, performing 10+ sets produced almost twice the gains as performing less than 5 weekly sets per muscle (9.8% vs 5.4%). Performing 10+ weekly sets per muscle was also associated with a markedly greater increase in muscle mass compared to 5-9 sets (9.8% vs 6.6%). Thus, a higher volume approach is clearly necessary if you want to maximize muscular gains.
So how many sets should you perform to maximize hypertrophy? That remains to be determined. While 10+ weekly sets per muscle was established as a minimum threshold, we were not able to determine an upper threshold where optimal muscle growth is achieved. The effects of volume on hypertrophy undoubtedly follows an inverted-U curve, whereby results progressively increase up to a certain point, then level off, and then ultimately decrease at exceedingly high volumes due to the negative consequences of overtraining. Moreover, the adaptive response to volume will be specific to the individual, with some lifters able to benefit from higher volumes more so than others. Thus, experimentation is needed to tweak the number of sets you perform based on how you respond.
It may well be that periodized approach is best here. Given that repeatedly training with high volumes can lead to an overtrained state, cycling from lower to higher volume blocks that culminate in a brief period of functional overreaching would hypothetically allow for sustained muscular gains over time while staving off the potential for overtraining. It’s a strategy that I’ve employed with good success when working with clients.
Interestingly, a previous study indicated that higher volumes were beneficial for the lower but not upper body musculature. A follow-up study by the same research group similarly found that satellite cell activation was dependent on volume only in the lower body musculature. However, our pooled analysis did not support these findings. Rather, volume was equally important irrespective of body region, with higher volumes translating into greater increases in size.
A limitation of the analysis is that the findings are largely specific to the muscles of the upper arms and frontal thighs; there simply isn’t enough evidence to generalize results to other body regions (i.e. muscles of the back, shoulders, chest, calves, etc). What’s more, the vast majority of studies were carried out in untrained subjects; only two studies used resistance-trained individuals. It has been speculated that increasingly higher volumes are necessary as one gains lifting experience, but more research is needed to support such a conclusion. My lab currently has a large scale study in development to investigate the topic in well-trained men that should help to fill in the gaps in the current literature. Stay tuned…
Uncategorized
January 23, 2024
Deloads, defined as a “period of reduced training stress,” are a popular strategy designed to attenuate accumulated fatigue and diminish the potential for nonfunctional overreaching after a period of intense training. Although deloads are often implemented by reducing training volume and/or intensity, by definition they can be employed as a relatively brief period of complete training cessation (i.e., detraining periods) to facilitate recovery.
Intriguingly, some evidence suggests that short-term detraining can potentially “resensitize” muscle tissue to potentiate anabolism. For example, a recent study showed that anabolic intracellular signaling was blunted after a 4-week resistance training program; however, signaling was restored to baseline levels after a 10-day cessation from training. Other research indicates that brief detraining periods can upregulate genes associated with muscle hypertrophy and increase testosterone levels, which conceivably could enhance muscle development.
However, acute findings do not necessarily translate into long-term gainz. No previous study had endeavored to investigate whether deloads actually enhance muscular adaptations, making any conclusions on the topic speculative…
Until now…
Our lab set out to assess the effect of deloads, when implemented as a brief period of detraining, on measures of muscular strength, hypertrophy, power and endurance. The study was led by our grad student, Max Coleman, who carried out the investigation in completion of his master’s thesis.
If you want to delve into the fine points of the methods and findings, you can read the study here. Alternatively, if you prefer a consumer-friendly synopsis, here’s the scoop…
What We Did
We recruited 50 resistance-trained men and women to perform a 9-week training program; participants were randomized to either perform the entire training program consecutively over the 9-week period (TRAD group) or to train for 4 weeks, take a 1-week layoff, and then train for another 4 weeks (DELOAD group).
The training program was the same for both groups, comprising 4 weekly sessions structured as an upper-lower body split. Our research staff directly supervised the lower body portion of the program, which included 5 sets of the squat, leg extension, straight-leg calf raise and bent-leg calf raise per session. We provided participants with an upper body program to perform on their own, which included 5 sets of shoulder press, lat pulldown, chest press, biceps curl and triceps pushdown per session; participants provided written logs of their sessions to the research staff on a weekly basis. Participants carried out all sets to failure in the supervised sessions and were instructed to do the same for their unsupervised sessions.
We assessed the following measures before and after the training program: (1) body composition via bioelectrical impedance analysis; (2) muscle thickness of the mid- and lateral quadriceps (upper, mid and lower sites) and the calves (medial and lateral gastrocnemius and soleus) via ultrasound; (3) lower body maximal strength in the squat via 1 repetition maximum testing and isometric knee extension via dynamometry; (4) lower body muscular power via the countermovement jump test; (5) lower body muscular endurance (AMRAP) via the leg extension using 60% of the participant’s initial weight. We also employed a readiness to train questionnaire that subjectively assessed participants’ feelings about the training program across the study period.
What We Found
Although both groups increased their strength from pre-study testing, gains were modestly greater in the TRAD group. Specifically, 1RM squat and isometric knee extension favored TRAD by 4.5 kgs and 11.5 newton-meters, respectfully. Notably, all other measures of body composition, hypertrophy, power and muscular endurance were relatively similar between groups.
What Do the Results Mean?
Contrary to what some may have expected (including me), the deload did not have a appreciable beneficial effect on muscular adaptations. In fact, there was a modest negative effect on maximal strength gains. Even though we pushed the participants really hard, verbally encouraging them to reach muscular failure on each set in a routine that could be considered of moderately high volume (90 total sets per week), the deload period did not seem to facilitate rejuvenation, nor was there evidence of a “resensitization” of muscle for anabolism. On the surface, some may interpret this to mean that deloads are useless.
But hold on…
The results of a study can only be extrapolated to the specifics of the methodological design. To this end, there are a number of factors that must be considered when attempting to draw practical conclusions:
1. The deload employed a complete cessation of training for one week. As mentioned, we used this approach based on evidence that there can be a “resensitization” of muscle after a short period of detraining, thereby enhancing anabolism. However, a popular alternative strategy is to deload with a reduced volume/intensity/frequency of training. There are numerous ways in which such a strategy can be implemented. We thus cannot necessarily extrapolate the findings to other deload approaches.
2. The study employed a deload after four weeks of intense training, regardless of whether participants felt they needed one. Although the findings indicate that deloads may not be beneficial after this relatively short period of time, it does not necessarily mean that continued intense training may not benefit from deloads over longer time frames.
3. To provoke overreaching and thus create a potential need for deloading, we employed what many would consider a relatively high-volume training program (90 sets per week) with all sets performed to volitional muscle failure. However, we only supervised the lower body portion of the training program. Although we received weekly training logs from each subject to verify their upper body progress, we do not know how intensely they trained. Based on my experience, I’d say it is highly likely that the majority of participants did not train as hard during their unsupervised training sessions as in their supervised sessions, conceivably reducing the need for a deload. Moreover, many bodybuilders perform substantially higher total training volumes, which may necessitate more frequent deloads. These factors warrant further study.
4. The participants were all young adults (average age ~22 years). It is well-established that recovery needs increase as we age. Thus, we cannot necessarily generalize the results to those 40+ years of age, who conceivably may benefit from periods of reduced training.
5. Although the participants all had at least a year of resistance training experience (average of ~3 years), they would not be considered elite lifters or bodybuilders. It’s conceivable that very advanced lifters may require more recovery due to the use of very high absolute training loads. This would particularly be the case for powerlifters and other strength-oriented athletes, who grind out reps with heavy compound lifts (our study employed a moderate rep range typical of bodybuilding programs) and thus may experience joint-related issues as well as central nervous system fatigue if recovery is not well-managed.
Take-Home Conclusions
The findings of our study can be looked at from a couple of different perspectives. On one hand, the deload had no detrimental effects on muscle development. In this context, you can take a week off every month or so and have peace of mind that you’ll maintain your muscle mass. Essentially, you can do less work over time without suffering negative consequences from a physique standpoint. Alternatively, if your goal is to maximize strength, this may somewhat hinder results.
On the other hand, there is seemingly no benefit to take regimented deloads every four weeks. Based on our research, it appears that most would not need a deload for at least 8 weeks if not longer, although this would ultimately vary from person to person.
I’d note the study has caused me to question my previous opinion on the implementation of deloads. I was of the belief that lifters generally do not have a good grasp of their recovery requirements, and thus they would only realize the need for a deload after they were nonfunctionally overreached. I thus advocated for deloads every month or so after a period of intense training to ensure recovery and rejuvenation.
Our study indicates this belief was unfounded.
Virtually every lifter stated they did not feel the need for a recovery week at the end of the 9-week study period, including those in the group that didn’t deload, and this seemed to play out in the results. So contrary to my thought process, it would seem that experienced lifters can in fact sufficiently gauge their need for recovery. Thus, my opinion has now shifted to recommend autoregulated deloads, where lifters implement a deload when they feel they need one. This hypothesis remains to be studied.
Stay tuned…
Entries (RSS)
