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Hypertrophy, Strength Training, Uncategorized

December 5, 2016


What is the Best Rep Range for Muscle Strength and Size?

Dating back to my early years as a personal trainer in the mid-90’s, I began to become intrigued by the concept of “loading zones” whereby different rep ranges purportedly could bring about differential effects on muscular adaptations. Prevailing wisdom at the time was that heavy loads (1-5 RM) promote maximal strength gains, moderate loads (6-12 RM) elicit maximal increases in muscle mass, and light loads (15+ RM) produce the greatest improvements in local muscular endurance. This concept, discussed extensively in exercise science texts, was termed the “strength-endurance continuum” (see the image below) although direct research on the topic was limited.
strength-endurance

The topic of rep ranges was so intriguing to me that I ultimately made it a focus of my doctoral work. Several years ago I published the data collected in accordance with my dissertation study. In brief, the study looked at muscular adaptations in a “bodybuilding-type” routine versus a “powerlifting-type” routine in resistance-trained men when the routines were equated for volume load. Consistent with the “strength-endurance continuum” concept, the study found that the powerlifting-type routine produced the greatest strength increases. Contrary to prevailing wisdom, however, both routines produced similar increases in hypertrophy of the biceps brachii. You can read my write-up of the routine in this blog post.

Importantly, the findings of that study are specific to the respective routines being equated for volume load. While this provides interesting insights on the topic, it is impractical to carry out long-term training with very heavy loads at the volumes used in that study (in fact, the majority of subjects in the powerlifting-type group displayed clear signs of overtraining by study’s end). So the question arises as to whether results would differ if an equal number of sets were performed between heavy and moderate loads?

Recently I carried out a study that investigated this very topic. The study was just published in the Journal of Sports Science and Medicine.

Here’s the lowdown.

What We Did
Nineteen college-aged men were recruited to participate in the study. All subjects had at least one year of resistance training experience lifting at least three times per week. Subjects were randomized to either a group that trained in a heavy loading range of 2-4 repetitions per set (HEAVY) or a group that trained in a moderate loading range of 8-12 repetitions per set (MODERATE). All other aspects of the subjects’ program were kept constant between groups. The training protocol consisted of seven exercises that worked all the major muscles of the body each session, with three sets performed per exercise. Training was carried out on three non-consecutive days per week for eight weeks. Subjects were instructed to maintain their normal daily nutritional intake and no differences in either calories or macronutrient consumption was found between groups over the course of the study.

What We Measured
We tested hypertrophy of the elbow flexors, elbow extensors, and quads using b-mode ultrasound. Maximal strength was assessed in the squat and bench press via 1 repetition maximum (RM) testing. Upper body local muscular endurance was determined by assessing the subject’s initial 1RM in the bench press for as many repetitions as possible to muscular failure.

What We Found
infograph_hypertrophy_study
The infographic to the left (courtesy of Thomas Coughlin) illustrates the results of the study. In general, overall muscle growth was greater for MODERATE compared to HEAVY. Increases in thickness of the elbow flexors (i.e. biceps brachii and brachialis) modestly favored the use of moderate reps (~5% vs ~3% for MODERATE vs HEAVY, respectively) while gains in the quads substantially favored the moderate rep group (10% vs 4% for MODERATE vs HEAVY, respectively). Interestingly, growth of the triceps was similar between groups.

On the other hand, strength gains were decidedly greater when training with heavy loads. This was seen for improvements in both the 1RM squat (29% versus 16%) and bench press (14% vs 10%), which favored HEAVY compared to MODERATE. Muscle endurance increases were similar between rep ranges.

What are the Practical Implications
The study provides evidence that training with heavy loads helps to maximize muscle strength and training with moderate loads promotes greater increases in muscle mass. Importantly, these findings are specific to routines where the number of sets are equated. At face value, this is consistent with the “strength-endurance continuum” and supports what gym bro’s have been preaching for years in regards to rep ranges.

However, when the results are taken into account with my previous study on the topic that equated volume load, an interesting hypothesis emerges. Since strength gains were greater with heavy loads in both studies, it can be concluded that low-rep training is best for maximizing strength regardless of volume load. On the other hand, since the previous study showed no differences in hypertrophy between conditions when volume load was equated, it can be inferred that volume load is a greater driver of muscle growth irrespective of the rep range. In other words, strength is maximized even with lower training volumes provided heavy loads are used, but higher volumes are needed to maximize gains in size whether you train with moderate or heavy weights.

The study had several limitations including a relatively small sample size, the use of a single-site measurement for muscle growth on each of the respective muscles, and possible confounding from the “novelty factor” (i.e. virtually all the subjects trained with moderate loads, so it is possible that the novel stimulus for those in the heavy load group might have impacted results). These issues must be taken into account when attempting to draw evidence-based conclusions. Most importantly, one study is never the be-all-end-all when it comes to answering questions on an applied science topic. Rather, each study should be considered a piece in a puzzle that lends support to a given theory. The practical implications of programming loading zones will become increasingly clear as we continue to build on this line of research. For now, though, the evidence suggests to train heavy if your goal is maximal strength, and to focus on accumulating volume for maximal gains in muscle mass.


Uncategorized

January 23, 2024


Are Deloads Useless?

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…

 

 

 

 

 

 


Bodybuilding, Strength Training

October 1, 2022


Do You Have to Add Load to the Bar to Build Muscle?

Progressive overload is a well-established principle for achieving continued progress in resistance training programs. In general terms, progressive overload can be defined as consistently challenging the neuromuscular system beyond its present capacity. It’s commonly accepted that this requires an increase the amount of weight on the bar as one gets stronger to maintain the intensity of effort in a targeted loading zone (i.e., repetition range). However, little attention has been given to other methods of progressive overload, such as increasing the number of repetitions over time. Surprisingly, no study to date had endeavored to investigate the topic in a controlled fashion.

Until now…

We sought to fill this gap in the literature with our just-published study, Progressive overload without progressing load? The effects of load or repetition progression on muscular adaptations. Before getting into the the specifics, first a little background info…

This study actually was the brainchild of my colleague, Jared Feather. Jared was planning to carry out this study as part of his doctoral work several years ago. He contacted me in 2019 about the possibility of conducting the study under my supervision at Lehman (he had intended to pursue his doctorate at AUT in New Zealand but collect data in the USA). Ultimately, Jared decided to forego his doctorate for the time being to work for Renaissance Periodization. That said, we discussed the importance of filling a gaping gap in the literature and concluded that the topic needed to be investigated regardless. Thus, I agreed to take on the project and carry out data collection in my lab.

In Spring 2020, we set out to conduct the study. We were about halfway finished with data collection when Covid-19 hit; by mid-March, we had to cease all research-related activities. Our research team had devoted over 500 hours of time to the study, but sadly it was all for naught; none of the data could be used.

Despite this setback, we were determined to complete the study.

Fast forward to Fall, 2021. My master’s degree student, Daniel Plotkin, expressed his interest in taking on the study for his thesis, with support from our terrific team of research assistants at Lehman. (Side note: Daniel has since graduated our program and is now pursuing his PhD under the mentorship of Dr. Mike Roberts at the University of Auburn). Fortunately, there were no issues with Covid this time around, We finalized data collection and statistical analysis in Spring 2022, and received official word of acceptance of our manuscript from PeerJ in September 2022.

If you want to delve into the technical aspects of the methods and findings, give the paper a read; it’s open access. For those who’d prefer a consumer-friendly synopsis, here’s the scoop…

What We Did

We randomized a cohort of young men and women with at least 1 year of consistent resistance training experience to perform a lower body training program where they either aimed to increase load while keeping repetitions constant or to increase repetitions while keeping load constant. The training protocol itself was otherwise identical between groups, consisting of 4 sets of the back squat, leg extension, straight-leg calf raise and seated calf raise performed twice per week. Training lasted 8 weeks, with testing performed pre- and post-study. To evaluate muscular adaptations, we carried out a battery of assessments including changes in muscle thickness of the quads and calves via B-mode ultrasound, total and regional body composition via multi-frequency bioelectrical impedance analysis, and 1RM in the Smith machine squat.

What We Found

Overall, results for most measures were quite similar between groups. Rectus femoris growth modestly favored the group that progressed by adding reps; hypertrophy of the other muscles did not show appreciable differences between conditions (see image below). Although strength increases slightly favored the group that progressed by increasing load, the range of effects spanned from relatively modest negative effects to appreciable positive effects and thus are of questionable practical meaningfulness. Other tests of local muscular endurance and power showed no benefit to one progression model compared to the other.

What are the Practical Implications of Findings

The results of our study challenge the generally accepted theory that progression must be carried out through increases in load. In fact, increasing repetitions at the same load showed similar gains in hypertrophy in most of the muscles we assessed, and there was even a modest benefit for hypertrophy of the rectus femoris. While strength increases slightly favored the group that increased load, the results showed a wide spread of variance that calls into question their practical significance. When considering the findings as a whole, both progression models were effective in enhancing muscular adaptations in a cohort of trained lifters and can be considered viable programming options.

Now before jumping to absolute conclusions, it’s important to note that the study only lasted 8 weeks. Although this is typical of training mesocycles, particularly for those of more advanced lifters, we cannot necessarily extrapolate results over longer time periods. Thus, our findings do not necessarily mean that a lifter can continue to simply increase reps forever without adding load to the bar at some point. Evidence suggests that training with very high rep ranges (>40 or so per set) tends to impair increases in hypertrophy. This would seem to be most relevant to those with less resistance training experience, as the ability to increase reps to such an extent is diminished in well-trained lifters. Hence, it’s conceivable that more advanced lifters can continue progress by adding repetitions for longer periods of time; this hypothesis warrants further study.

I’d also note that our protocol targeted a moderate repetition range for the initial training loads (10RM). It is well-documented that maximal strength gains are achieved with the use of heavy loads (at or near 1RM). Thus, these results are not necessarily applicable to strength athletes (e.g., powerlifters) or those who are most concerned about optimizing dynamic strength. In these cases, some type of load progression seemingly would be necessary to maintain training close to maximal loads.

Take-Home Conclusions

Overall, our study suggests that, from a hypertrophy standpoint, progressive overload can be made by altering load, repetitions, or conceivably a combination of the two, at least over the course of typical mesocycles (i.e., 8-week training block). Given that rectus femoris growth favored the repetitions groups, it is conceivable that progressing reps may be favorable in some contexts over others.

On a more general level, the mode of progression does not have to be an either/or choice. It may be best to employ a variety of progression strategies over time to ultimately elicit optimal improvements in muscular adaptations. In this regard, variety may be the spice of gainz.  


Uncategorized

March 15, 2018


The Mind-Muscle Connection: A Key to Maximizing Growth?

In this case, it appears the bros were right…!

For as long as I can recall, bodybuilders have been preaching the importance of a mind-muscle connection for maximizing muscle development. In case you’re not aware, a mind-muscle connection (a variation of the concept in the field of motor learning known as an “internal focus of attention”) is the process of actively thinking about the target muscle during training and then feeling it work through the full range of motion. According to theory, this strategy maximizes stimulation of the muscles you’re trying to target in a given exercise while reducing the involvement of “secondary” movers. This combination hypothetically should result in greater growth.

Hypothetically….

Numerous studies have confirmed that a mind-muscle connection does in fact increase activation of the target muscle as measured by a technique called electromyography. However, higher activation of a muscle doesn’t necessarily mean it will hypertrophy to a greater extent over the course of a long-term training program. To my amazement, no one had endeavored to investigate whether adopting a mind-muscle connection during training actually had a beneficial effect on muscle growth in a controlled, long-term study.

So the curious science nerd that I am, I took it upon myself to find out. Here’s the scoop on our recently published paper on the topic.

What We Did
30 college-aged men agreed to participate in the study and were randomly assigned to either train with an internal focus (mind-muscle connection) or an external focus. All participants performed 4 sets of arm curls and leg extensions for 8 to 12 RM on 3 non-consecutive days per week, with sets carried out to muscular failure. Every rep of every set was supervised by one of my research assistants. The mind-muscle group was instructed to “squeeze the muscle” on each rep while the external focus group was instructed to “get the weight up.” The exercise portion of the program lasted 8 weeks with a week taken for testing immediately before and immediately following the training period.

As those of you who follow my work undoubtedly know, the vast majority of my studies are carried out in subjects with resistance training experience. However, in this case I decided to use untrained subjects.

Why?

Well, trained individuals tend to get hardened into a given attentional focus (called a “deep basin” in motor learning). It’s therefore difficult to get these individuals to change their focus during training. This would be especially problematic in a study such as this since there is no way to be sure what the lifter is actually thinking when training. An untrained lifter is a blank slate and thus we could be more confident that he would follow the prescribed attentional focus strategy.

I also chose to use only single joint exercises for the study. The reasoning here is that it’s easier to focus on a given muscle during a single joint lift. Squats, rows and presses involve multiple primary muscle movers that makes it difficult for a lifter – particularly one with no training experience – to focus on a given single muscle. What’s more, multijoint exercises require more of a learning curve to coordinate movement patterns in the early stages of training, which would further impair the ability to develop a mind-muscle connection as well as delaying the onset of hypertrophy in favor of neural adaptations.

What We Found
After 8 weeks of consistent training, subjects who used a mind-muscle condition had almost double the muscle growth in the biceps brachii compared to those using an external focus (12.4% vs 6.9%, respectively). Alternatively, muscle growth for the quadriceps was similar between conditions. From a maximal strength standpoint, isometric strength of the elbow flexors increased substantially more for the internal focus group while knee extensor strength was markedly greater for the external focus group.

What We Learned
The novel finding of the study was that superior gains in biceps hypertrophy were made by employing an internal focus of attention. Based on these findings, it appears the bros were right; employing a mind-muscle connection enhances muscle growth.

But wait a sec; if that’s the case, then how come attentional focus did not seem to matter for thigh hypertrophy…?

Although it’s impossible to say for sure since we didn’t attempt to investigate mechanisms, a possible reason is that subjects simply found it easier to focus on the biceps as opposed to the quads. This is logical given that the upper extremities are used for fine motor skills (i.e. picking things up, writing, etc) while the lower extremities are involved in gross motor skills (i.e. walking, kicking, etc). Thus, people tend to be more conscious of their arm muscles and less so of the leg musculature. The fact that the subjects were untrained would seemingly contribute to this discrepancy. I’d hypothesize that well-trained lifters would be better able to focus on the quads when training and thus achieve better hypertrophy. This needs further study.

Here’s the take home: It appears beneficial to adopt a mind-muscle connection if your goal is to maximize muscle growth. Instead of worrying about a specific tempo, simply focus on the muscle being trained and visualize it working throughout the full range of motion. Now this comes with the caveat that findings are specific to a moderate rep range; using heavy loads (i.e. 3-5 reps) may preclude the ability to take advantage of this strategy as your focus would conceivably have to shift to just getting up the weight as efficiently as possible. Importantly, this is just one study and shouldn’t be taken as the be-all-end-all on the topic. Hopefully more longitudinal studies will be conducted on the topic to draw more definitive conclusions. Future research should look to compare internal versus external focus strategies using multi-joint exercises in trained lifters to better understand how a mind-muscle connection impacts growth.

For further insights, check out the video I did for Omar Isuf’s YouTube channel below. I discuss the nuances of the topic and their relevance to practical application in a lifting program.


Exercise, Hypertrophy

December 21, 2016


How long should you rest when training with lighter loads?

A popular theory among fitness professionals is that taking short rest periods between sets maximizes muscular growth. The theory is primarily based on the hormone hypothesis, whereby limiting inter-set rest promotes greater elevations in post-exercise growth hormone, IFG-1 and testosterone, and thus enhances the anabolic response to resistance training. One little problem: Emerging evidence indicates that acute increases in anabolic hormones have little if any effect on muscular adaptations, as detailed in my comprehensive review of the topic

In an effort to directly test the theory, our group published a study last year titled, Longer inter-set rest periods enhance muscle strength and hypertrophy in resistance-trained men. In brief, the study not only refuted the claim of a hypertrophic benefit to short rest periods, but in fact showed that resting 3 minutes between sets actually produced superior growth compared to resting 1 minute. Importantly, the study was carried out using a moderate rep range (8-12 reps/set) with all sets performed to muscular failure. The question therefore arises whether results would be applicable when training with lighter weights. No study had ever investigated the topic.

Until now…

In collaboration with colleagues in Japan, we sought to investigate the effects of low-load resistance training with different rest intervals on muscular adaptations. The study titled, Acute and Long-term Responses to Different Rest Intervals in Low-load Resistance Training, was just published in the International Journal of Sports Medicine.

Here’s the lowdown.

What We Did
Subjects were 21 young collegiate athletes who had not performed resistance training for at least 2 years prior to the study. The subjects were randomly divided into two groups: A short rest group (SHORT) that rested 30 seconds between sets and a long rest group (LONG) that rested 2.5 minutes between groups. The load was set at 40% of the subjects’ 1RM in the back squat and bench press using a tempo of 1-0-2 (1 second on the concentric, 2 seconds on the eccentric). Four sets were performed for each exercise, with all sets taken to muscular failure. Training was carried out twice a week for 8 weeks.

What We Tested
Measures of muscle hypertrophy and strength were assessed pre- and post-study. Muscle cross sectional area (CSA) of the triceps and thigh was measured by MRI. A 1RM bench press and squat was employed to measure changes in maximal strength.

What We Found
With respect to hypertrophy, the SHORT group increased muscle CSA by 9.8% while LONG showed an increase of 10.6%. Thigh CSA increased by 5.7% in SHORT versus 8.3% in LONG. No statistically significant differences were noted between any measure of muscle growth.

From a strength standpoint, 1RM in the bench press increased by 9.9% in SHORT and 6.5% in LONG while increases in the squat were virtually identical between groups (5.2% versus 5.4) As with the hypertrophy results, no statistically significant between-group differences were observed in the strength measures.

How Can You Apply These Findings
There are a number of interesting takeaways from the study. First and foremost, this is yet another study showing that training with light weights can promote marked gains in muscle mass in a relatively short time period. There is now a large body of supporting research on the topic using varied methodologies across a variety of populations. The evidence is too compelling for even the most ardent critic to dismiss.

Intriguingly, we found that rest interval length had no statistically significant effects on muscular adaptations. On the surface, these results conflict with our previous research showing that 3 minutes rest produced superior increases in strength and hypertrophy compared to resting 1 minute when training in a moderate rep range (~10RM). Our findings here seem to indicate that rest interval length isn’t an important consideration when training with lighter loads.

A closer look at the data, however, suggests a more nuanced take-home message.

thigh_csa
It’s important to realize that the term “statistical significance” refers to the probability of an event happening by chance. Our study had a fairly small sample size, which reduces the ability to detect significance. Hence, we have to look beyond whether results were “significant” and consider other statistical measures. To that end, while hypertrophy of the arms was fairly equal between conditions, gains in thigh muscle CSA clearly favored resting longer between sets. A statistic called the effect size, which is a gauge of the meaningfulness of the results, bears out these differences were indeed consequential. The effect size for the LONG group was 0.93 (considered a large effect) while that of the SHORT group was just 0.58 (considered a moderate effect). The chart above illustrates the absolute differences between thigh growth and rest intervals.

When attempting to reconcile the differences between upper and lower body hypertrophy, it may well come down to total training volume. Short rest blunted increases in training volume in both upper and lower training, but the disparity was much more pronounced in the squat than in the bench. This is logical as the leg/glute muscles have much greater muscle mass than those of the upper trunk/arms, and thus the associated fatigue during high-rep training is greater in multi-joint lower body training, particularly a demanding exercise like the squat. Given the known dose-response relationship between hypertrophy and volume (as clearly displayed in our recent meta-analysis on the topic), the substantial decrease in number of reps performed with short rest periods could conceivably explain the lesser muscle growth seen in the thighs.

In addition to the long-term effects, we also measured hormonal elevations from each condition post-exercise. Both SHORT and LONG showed significant acute spikes in growth hormone and IGF-1, but the increases were similar between groups. Since hormonal increases are related to levels of metabolic stress, it can be inferred that metabolic stress was similar between conditions as well. Although short rest periods have generally been shown to enhance metabolic stress, these findings are specific to moderate rep training. Training with very high reps elicits large increases in lactic acid regardless of how long you rest between sets. Thus, rest interval length seemingly has less relevance in promoting metabolite buildup. Whether metabolic stress influenced results in this study is undetermined as we didn’t seek to assess mechanisms of adaptations. That’s an intriguing topic for future research.

The Bottom Line

*  Training with light weights can pack on some serious muscle.

*  Short rest between sets has a detrimental effect on lower body hypertrophy when squatting while there does not seem to be much if any negative impact on growth from the bench press when training with light weights. Thus, shorter rest periods for light-load upper body work are a viable option to cut down on training time without sacrificing gains.

*  Since single joint exercise does not elicit comparable fatigue to multi-joint movements, it is conceivable that short rest would be similarly viable for single-joint lower body exercises such as the leg extension. This remains speculative, however, as the topic wasn’t directly investigated in our study.


Exercise, Hypertrophy, Studies

April 6, 2016


Is Daily Undulating Periodization Best for Muscle Growth?

If you follow my work you’ll undoubtedly know that our lab has carried out a number of studies seeking to determine the effects of training in different repetition ranges on muscle strength and growth. The overall findings from these studies showed similar increases in hypertrophy between both heavy and moderate rep ranges, as well as moderate and high rep ranges.

Undulated-Periodization
However, the choice of rep ranges is not necessarily an either-or proposition; you can in fact combine strategies to potentially achieve greater hypertrophic benefits. Daily undulating periodization (DUP) routines are specifically designed for this purpose. However, no study to date had compared a varied rep approach to traditional constant-rep training using site-specific measures of muscle growth.

Until now.

Our study, just published in the International Journal of Sports Medicine, set out to investigate if muscular adaptations would differ between DUP-style routine and a traditional hypertrophy-style protocol. Here’s the scoop.

What We Did
Nineteen young men with over four years average resistance-training experience were randomly assigned to 1 of 2 experimental groups that trained 3 days per week: a constant-rep protocol (CONSTANT) that trained using a standard bodybuilding rep range of 8-12 RM per set, or a DUP-style varied-rep protocol (VARIED) that trained with 2-4 RM per set on Day 1, 8-12 RM per set on Day 2, and 20-30 RM on Day 3. All subjects performed a total-body routine consisting of the following seven exercises per session: flat barbell press, barbell military press, wide grip lat pulldown, seated cable row, barbell back squat, machine leg press, and machine knee extension. We tested subjects for changes in hypertrophy of the arm flexors, elbow flexors and quads, as well as maximal strength in the squat and bench press, and upper body muscle endurance. Training was carried out over an 8-week period, with testing done pre- and post-study.

Table
What We Found
Both groups significantly increased markers of muscle strength, muscle thickness, and local muscular endurance. No statistically significant differences were found between conditions in any of the outcomes studied. Sounds like it really doesn’t matter which option you choose, right?

Well, not so fast…

It’s important to understand that the term “statistically significant” simply refers to the probability of results being due to chance at a predetermined level of 5%. This binary method of determining probability has been widely criticized by those in the know about statistics, who proclaim that practical conclusions cannot be drawn merely on the basis of whether a p-value passes a specific threshold. Rather, probability exists on a continuum, and in this regard the p-values (a measure of probability) in our study favored the VARIED condition in several outcome measures. Moreover, magnitude-based statistics (i.e. effect sizes) indicated a benefit to the VARIED condition for upper body hypertrophy, strength, and muscular endurance; no effect size differences were noted for lower body outcomes.

What are the Practical Implications
The study showed a potential benefit – albeit small – to varying repetitions across a spectrum of ranges for increasing upper body muscle strength and hypertrophy. Whether the differences between the varied versus constant rep approach seen in our study would amount to practically meaningful improvements is specific to the individual. For the average gym-goer it probably wouldn’t be of much consequence; alternatively, to a bodybuilder or competitive athlete it very well may. It’s not clear why these findings did not translate into similar differences in lower body muscular adaptions, but based on our findings either approach would seem to be an equally viable choice for leg training.

It’s important to note that this was a relatively short-term study, lasting a total of 8 weeks. When factoring in missed sessions, this means subjects in VARIED trained in each loading zone for a total of only 7-8 sessions over the course of the study period. If the differences in upper body outcomes favoring VARIED would persist over time – highly speculative but certainly possible – the magnitude of results could widen and thus be potentially meaningful for a wide array of fitness enthusiasts.

Another important point is that volume load was consistently lower across all conditions (pushing exercises, pulling exercises, leg exercises, and total volume of all exercises) in VARIED as compared to CONSTANT. This indicates that training in a varied fashion provides comparable or better results with less volume load than training at a constant 8-12 RM repetition range. It also suggests that if volume load were equated between conditions, there might have been even better results for the varied approach.

In sum, our study shows that both varied and constant loading schemes are viable strategies to increase strength and hypertrophy in resistance-trained men. The data suggest a potential modest benefit to varying loading ranges over time, at least for maximizing upper body muscular adaptations. Importantly, findings clearly indicate that contrary to what many believe, training in the “hypertrophy zone” (6-12 RM) is not superior for building muscle. When considering the practical implications of the findings, remember that exercise prescription is always a function of the needs/abilities/goals of the individual.


Hypertrophy, Strength Training

February 5, 2016


What is the Ideal Rest Interval for Muscle Growth? Implications from Our Recent Study

Current resistance training guidelines recommend long rest intervals (i.e. 3 minutes) to maximize muscle strength. Alternatively, short rest intervals of around 1 minute are generally recommended for maximizing muscle growth. This is based on the premise that higher metabolic stress associated with limiting rest between sets will promote a greater muscle-building stimulus. Some have specifically pointed to acute post-exercise increases in anabolic hormones as a primary driving factor in the process.

Back in 2014, I co-authored a review paper on the topic with my colleague Menno Henselmans that was published in the journal Sports Medicine. After a thorough scrutiny of the literature, we determined that there was little basis for the claim that shorter rest intervals was beneficial to hypertrophy. As I discussed in this blog post, It would appear from current evidence that you can self-select a rest period that allows you to exert the needed effort into your next set without compromising muscular gains. That said, our recommendations were limited by a dearth of controlled studies on the topic. Moreover, no study had investigated the generally accepted guidelines of taking 3 minutes rest for strength gains and 1 minute for hypertrophy in resistance-trained individuals.

Until now…

I recently collaborated on a just-published study that investigated the effect of rest intervals on strength and hypertrophy. Here’s the scoop:

What We Did
A cohort of 21 young men were randomly assigned to either a group that performed a lifting routine with 1- or 3-minute rest intervals. All other resistance training variables were held constant. Subjects performed a typical bodybuilding-style routine that comprised 7 different exercises working the major muscle groups of both upper and lower body. Three sets of 8-12RM were performed per exercise. Training was carried out 3 days a week for 8 weeks.

We tested subjects immediately before and after the study period. Tests for muscle strength included 1RM for the bench press and back squat. Muscle-specific growth was assessed by b-mode ultrasound for the elbow flexors, triceps brachii, and quadriceps femoris.

What We Found
Maximal strength was significantly greater for both 1RM squat and bench press for the group taking longer rest. No big surprise here. Somewhat unexpectedly, however, muscle thickness tended to be greater when taking longer rest intervals as well. Although we can’t be sure of the underlying mechanisms, we speculated that results may be attributed a reduction in total volume load (i.e. reps /x/ load) over the course of the study. There is a well-established dose-response relationship between volume and hypertrophy, whereby higher volumes correlate with greater muscle growth. Thus, very short rest periods may compromise growth by reducing the amount of weight you can use on subsequent sets. This would indicate that if there are synergistic benefits to heightened metabolic stress, they are overshadowed by the associated decreased volume.

What are the Practical Implications
The obvious take-home here would seem to be that resting 1 minute between sets compromises gains in muscle size. But if 1 minute is in fact too short a rest period, how long should you then rest when maximal hypertrophy is the goal? Well, based on previous work in well-trained individuals, it would seem that 2 minutes provides sufficient recovery so as not to undermine growth.

That said, it’s important to take these results in proper context. Realize that we looked only at effects of the two respective conditions (i.e. 1- versus 3-minutes rest) on muscular adaptations. But rest interval length does not have to be a binary either-or choice. There is no reason you can’t combine different rest periods to potentially maximize hypertrophy.

A viable strategy is to take longer rest intervals on your large-muscle compound exercises such as squats, presses and rows. These movements generate very high levels of metabolic disturbance, particularly when performed with moderate rep ranges (i.e. 8-15 reps). Thus, longer recovery periods are needed to fully regenerate energy levels for your next set so that volume load is maintained across sessions.

On the other hand, single joint movements are not as metabolically taxing and thus you’re able to recover more quickly from set to set. Exercises like biceps curls, triceps pressdowns, and leg extensions therefore could conceivably benefit from shorter rest periods. In this way, you can heighten metabolic stress and its potential hypertrophic benefits without negatively impacting volume load. In this scenario, it’s best to keep the short-rest sets at the end of your workout to ensure they don’t interfere with recovery of compound exercise performance.

A final word: Research is still emerging on this topic. Each study is simply a piece in a puzzle. As more studies are carried out we’ll hopefully develop a better understanding of how programming can be tweaked to maximize the growth-related response. Stay tuned.


Exercise

March 29, 2015


Have You Reached Your Muscle-Building Potential?

“You’re done!”

These are the words of a noted fitness trainer in response to a bodybuilder who spoke of packing on some additional muscle. The trainer went on to say that you can only gain muscle for a couple of years; after that, you’ve maxed out your genetic potential.

Done!

If the trainer is indeed correct in his claim, then everyone with a modicum of training experience is basically spinning his wheels in the gym; might as well just do a couple of 15 minute HIT workouts and maintain what you’ve got. Fortunately for those of us who aspire to keep making gains, the comments made were both misguided and uninformed.

Don’t get me wrong. There certainly are upper limits to how much muscle you can build, just as there are limits to muscular strength, aerobic endurance, and any other exercise-induced adaptation. This is commonly known as your “genetic ceiling”; at a certain point, you hit your ceiling and further gains cease.

Thing is, how do you know if you’ve reached your genetic ceiling?

Answer: You don’t.

In fact, you can’t.

All you can ascertain is whether or not your training regimen is producing positive changes in your physique. And if you’re not in fact growing from your present routine, that doesn’t mean you might not see results from an alternative strategy. The number of possible ways to vary program design is virtually unlimited. Unless you try each and every alternative, there’s no way to know if another approach might be the ticket to further gains.

Understand that the reason your muscles adapt to an exercise stimulus is a function of survival. Your body doesn’t realize the reason you hit the gym is to look jacked in a tank-top; rather, it senses a high degree of physical stress that is deemed a threat to survival. In response, a coordinated series of intracellular events are initiated to strengthen the muscles and supporting tissues so that they are better prepared the next time you lift.

Adaptation!

Problem is, the more you continue to provide similar stimuli, the less of a need for future adaptation. Further growth can only occur by subjecting your muscles to a novel overload stimulus.

The imprudent nature of the comments made by the aforementioned trainer is reflected in his own training practices. Namely, he is known to perform the same basic routine over and over each and every year. Why would the body respond to a stimulus that it perceives it can readily handle?

Answer: It won’t.

While a “ceiling” may exist in theory, you never actually realize your full genetic potential; there is always the ability to further increase muscle mass. Indeed, muscular gains can be made even at very advanced levels, albeit at a much slower pace than when you first started training.

Numerous research studies – including those from my own lab – show that those with considerable training experience do in fact build appreciable muscle when a novel stimulus is applied. Thus, the claim that a couple of years hitting the weights maxes out your genetic potential is patently false. Because of the difficulties in carrying out studies on those near the limits of their hypertrophic ceiling, research on this population is scant. That said, I recently collaborated with a group in Brazil on a study involving off-season pro bodybuilders who weren’t using performance enhancing drugs (the study is currently in journal review). Suffice to say, significant gains in fat-free mass (as measured by DXA) were noted after just 4 weeks of intense training. Anecdotally, I’ve worked with numerous competitive natural physique athletes who’ve added several pounds of lean body mass over the course of a regimented hypertrophy training phase.

Now the closer you get to your individual ceiling, the more essential it is to take a scientific approach to training and nutrition. From a training standpoint, this entails precise manipulation of resistance exercise variables. Here, the concept of “progressive overload” needs to be expanded beyond simply increasing load within a given rep range. Adaptation can and should be achieved by varying loading zones as well. If nothing else, changing up loading patterns provides a novel stimulus to your muscles that can spur new growth. Moreover, emerging evidence suggests that heavy, moderate, and light loads promote fiber type-specific increases in growth that can maximize whole muscle hypertrophy. Perhaps more importantly, volume of training should be progressively increased, culminating in a high-volume phase designed to promote functional overreaching. When properly executed, this results in a supercompensatory response that increases muscle in even the most advanced lifters. Many other advanced lifting strategies also can be employed to enhance results; you’re only limited by your determination and base of knowledge.

Bottom line; If someone tells you that you’re done adding muscle, pay them no heed. It’s a self-limiting attitude that will keep you from achieving your full genetic potential.


Hypertrophy, Studies

August 13, 2014


Does Low-Load Resistance Training Fully Activate the Target Muscles?

There is compelling evidence that the onset of fatigue during resistance training results in an increase in motor unit activation, whereby the strength-oriented type II fibers are progressively recruited to sustain muscular contractions. Some have taken this to mean that any load, regardless of how light, will ultimately lead to full fiber recruitment provided that training is carried out to muscle failure (i.e. the point where you are unable to complete an additional rep with proper form).

Recently, my lab sought to test this hypothesis. Here is an overview of the study and its practical implications. The study, titled, Muscle activation during low- versus high-load resistance training in well-trained men, was just published ahead-of-print in the European Journal of Applied Physiology.

The Study
The purpose of the study was to compare muscle activation in the leg press at 30% and 75% 1RM when sets are carried out to muscular failure. Ten college-aged men were recruited for participation. Subjects were all experienced in resistance training, including regular performance of lower body exercise.

A within-subject design was employed where each participant performed both 30% and 75% 1RM conditions. Testing was carried out over two sessions. Subjects were initially tested to determine their 1RM in the leg press. They then returned to the lab at least 48-hours later for muscle activation testing of the quads (rectus femoris, vastus lateralis, and vastus medialis) and the hamstrings (biceps femoris) during heavy- vs. light-load training. The order of performance was counterbalanced whereby Subject 1 performed the high-load condition first, Subject 2 performed the low-load condition first, etc. In this way, we ensured that order of performance did not confound results. Fifteen minutes rest was provided between trials to ensure that previous fatigue was not a factor. We verbally encouraged subjects to perform each set to the point where they could physically no longer continue training with proper form.

Results
Both mean and peak muscle activation was markedly and significantly greater during the heavy- compared to light-load condition (by 57% and 29%, respectively). Importantly, not a single subject displayed equal or greater activation during low-load training. These findings strongly suggest that training at 30% 1RM in a compound lower-body exercise is insufficient to recruit the entire motor unit pool for the target musculature.

Practical Implications
It has been well-established that training to muscle failure causes an increase in motor unit recruitment. This outcome was in fact confirmed in our study, as EMG amplitude increased in both the high- and low-load conditions over the course of each set. However, the magnitude of these increases were substantially lower during light- versus heavy-loading. The take home message here (in conjunction with a recent study on the topic using single-joint lower body exercise) indicates that a minimum threshold exists to achieve activation of the full spectrum of fibers and that 30% 1RM is below this threshold. Thus, it can be inferred that some of the highest threshold motor units — those associated with the type IIx fibers — were not recruited during the low-load condition.

From an applied standpoint, it might seem that these findings show training at very low-loads is useless. After all, why would you train with a load that does not generate complete fiber recruitment, right?

Not so fast.

Understand that there are two aspects to maximizing muscle development: recruiting a fiber and then keeping it stimulated for a sufficient period of time (i.e. time under load). While the loading strategy used in the light-weight condition here (i.e. 30% 1RM) did not bring about full muscle activation, it did maintain tension in the lower-threshold motor units for an extended time period. This could be particularly important in optimizing development of the type I fibers that are highly fatigue-resistant. This lends credence to the hypothesis that training throughout the full spectrum of rep ranges is the best strategy for maximal muscle hypertrophy. I have a longitudinal training study currently in review that seems to support this hypothesis. More on that in the near future.

An interesting secondary finding of the study was that the hamstrings displayed only minimal activation during the leg press — much less than that seen in the quads. This refutes the claims by some fitness pros that single-joint exercise is unnecessary provided you perform compound lower body exercises. Our results clearly indicate that movements such as the leg curl, stiff-leg deadlift, and good morning are important components of a well-rounded resistance training program to ensure proper symmetry between the quads and hamstrings.

A limitation of the study is that we only assessed a single set at each condition. Thus, it is not clear whether accumulated fatigue from performing multiple light-load sets would ultimately bring about complete recruitment. This requires further study. But even if this turns out to be the case — which is far from a certainty — it would mean that you’d need to perform a lot of additional volume just to achieve similar levels of activation; at the very least, an inefficient training strategy.

Final Thoughts
I am in the process of finishing a follow-up bench press study looking at 80% vs. 50% 1RM in an attempt to determine the approximate minimum threshold necessary for complete muscle activation. This will provide important info to those who are unable to lift heavier weights due to medical conditions or other issues. Realize, though, that muscle activation (and hypertrophy for that matter) do not necessarily translate into optimal strength gains. My recent study showed that even moderate load training (~10 RM) is inferior to very heavy lifting (~3 RM) if absolute strength is the goal. I discussed that study in-depth in this blog post

On a side note, I’ll be discussing the ramifications of this study and others currently in progress at my upcoming seminar in Montreal next month. Hope to see you there!

References

Cook SB, Murphy BG, Labarbera KE. Neuromuscular function after a bout of low-load blood flow-restricted exercise. Med Sci Sports Exerc. 2013 Jan;45(1):67-74.

Schoenfeld BJ, Contreras B, Willardson JM, Fontana F, Tiryaki-Sonmez G. Muscle activation during low- versus high-load resistance training in well-trained men. Eur J Appl Physiol. 2014 Aug 12. [Epub ahead of print]

Schoenfeld BJ, Ratamess NA, Peterson MD, Contreras B, Tiryaki-Sonmez G, Alvar BA. Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men. J Strength Cond Res. 2014 Apr 7. [Epub ahead of print]


Exercise, Hypertrophy

April 11, 2014


Bodybuilding- vs. Powerlifting-Type Training: Which Builds More Strength and Muscle?

muscle
I’m stoked to announce that my dissertation study, Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men, was just published ahead-of-print in the Journal of Strength and Conditioning Research. I had actually devised the protocol during my master’s degree course in research methods back in 2008. The study I ultimately carried out had some different wrinkles than the one originally proposed, but overall the essence remained the same. Most importantly, it investigated a topic that’s been debated for many years: What are the differences in muscular adaptations (strength and hypertrophy) between bodybuilding- vs powerlifting-type training programs? Here is an overview of the study and a discussion on its practical implications.

The Methodology
20 well-trained subjects (minimum of 1 year resistance training experience working out at least 3 days/week) were recruited to participate in the study. Subjects were randomly assigned to one of two groups: A hypertrophy group (HT) that performed a bodybuilding style routine or a strength group (ST) that performed a powerlifting-style routine. The HT protocol was a split routine where each muscle was worked once per week with 3 exercises per session, performing 3 sets of 10 reps and resting for 90 seconds. The ST protocol was a total body routine where each muscle was worked 3 times per week with 1 exercise per session, performing 7 sets of 3 reps. The volume load (sets x reps x load) was equated so each group essentially lifted about the same amount of total weight per week. Training was carried out over 8 weeks. All sets were performed to the point of momentary concentric muscular failure.

Strength was measured by 1RM in the squat and bench press. Muscle thickness of the biceps was measured with ultrasound. Testing was carried out pre- and post-study, and results were then compared between groups to assess differences in strength and hypertrophy.

The Results
3 of the subjects dropped out of the study before completion leaving 17 subjects for analysis (9 in the HT group, 8 in the ST group). Both groups significantly increased biceps muscle thickness by ~13% with no differences seen between groups. Both groups also significantly increased 1RM strength, but the ST group had greater increases in the bench press and showed a trend for greater increases in the squat.

Practical Recommendations
On the surface, the study showed that muscle hypertrophy is similar between powerlifting and bodybuilding type routines provided that volume is equated between protocols. Moreover, the study showed that maximal strength is slightly greater in a powerlifting protocol. This could lead to the conclusion that if your goal is hypertrophy then it doesn’t matter what rep range you use (at least in the heavy to moderately-heavy range) as long as you perform equal volumes, but that maximizing strength requires lifting very heavy weights. From a mechanistic standpoint with respect to muscle hypertrophy, the study suggests that either 1) the increased mechanical tension in the ST group was offset by the greater metabolic stress in the HT group on a volume-equated basis or, 2) there is a threshold for mechanical tension and once the threshold is reached, it doesn’t matter as long as the stimulus is maintained for similar timeframes. With respect to strength, this would suggest that neural factors related to training are still relevant in well-trained individuals, and that using very heavy weights does indeed have a greater transfer to maximal lifts compared to moderate intensity loads.

But the devil is often in the details and that is the case here.

First, it is important to point out that total training time in the ST group was 70 minutes while that of the HT group was 17 minutes. So from a time-efficiency standpoint, the bodybuilding-type training produced similar hypertrophy (as well as nearly similar strength increases) in about a quarter of the time as the powerlifting routine. Moreover, exit interviews revealed that those in the ST group were fried by the end of the study. Almost all of them complained of sore joints and general fatigue, and the two dropouts from this group were because of joint-related injury (and these routines were highly supervised with respect to form, so we took every precaution for safety). On the other hand, the HT group all felt they could have worked substantially harder and done more volume.

This brings up an important take-away message: While mechanistically it appears that it does not matter whether heavy or moderately-heavy weights are used for hypertrophy, from an application standpoint it simply isn’t practical to train constantly with the volumes used in this study on multiple body parts. The grinding on the joints and the taxation of the neural system that is involved with repeated performance of very heavy loads ultimately has a negative impact on the lifter; I am certain that if we had continued this program for any longer, most of those in the ST group would have been overtrained and seen performance decrements. If nothing else, these finding reinforce the importance of periodizing programs so that cycles of deloading are interspersed with very heavy loading protocols.

Additionally, realize that only three major muscle groups were worked in the study: the pecs (upper body pushing); the back (upper body pulling) and the thighs. Thus, the HT group could have easily done a couple of extra sets for each muscle group without overtaxing their resources. Although impossible to say for sure, it certainly is plausible that additional work would have enhanced the hypertrophic response in the bodybuilding-style training group. Moreover, the HT group could have performed exercises for other muscle groups, including some targeted work with single joint movements. Working specific muscles (and aspects of muscles) such as the middle and posterior delts, the hamstrings and the calves alone would definitely have benefited overall muscle hypertrophy.

So bottom line: The study indicates that the best approach to building muscle is to perform a combination of heavy and moderately heavy loads. The “hypertrophy range” is applicable from the standpoint that it allows the performance of a greater amount of volume without overtaxing the body’s resources. Adding in loads in the 1-5 RM range can enhance strength (which ultimately allows the use of heavier loads during moderate rep lifting) as well as providing a potent hypertrophic stimulus.

It should be noted that.I made a conscious decision to investigate the two types of routines as lifters usually perform them. Thus, the HT routine was a split routine since the vast majority of bodybuilders train in this fashion, while the ST routine was a total body routine since this is the way most powerlifters train. While staying true to the usual performance gives insight into how muscular adaptations generally play out in everyday practice, they also obscure the ability to attribute results entirely to the set/rep scheme. I will be carrying out a follow up study that seeks to address this issue in the near future. Stay tuned!