Wanted to keep you updated on all that is going on at the moment. So much to share! In case you haven't heard, my newest consumer book called Strong and Sculpted, was released a few weeks ago. Happy to report it's been the top-selling new book in Amazon.com's "weight training" categ...
Recent Blog Posts
June 7, 2016
Wanted to keep you updated on all that is going on at the moment. So much to share!
In case you haven’t heard, my newest consumer book called Strong and Sculpted, was released a few weeks ago. Happy to report it’s been the top-selling new book in Amazon.com’s “weight training” category and has gotten stellar reviews from consumers and pros alike. It’s a scientifically-based handbook for optimizing muscle development, providing step-by-step guidelines for program design. Check it out! In addition, my upcoming textbook called, Science and Development of Muscle Hypertrophy, is scheduled to be released at the end of the month. It will be the first text to provide an evidence-based perspective on muscle growth, covering all the research and its practical implications. If you’d like to be amongst the first to receive the book, it’s now available for pre-order on Amazon.com at a 20% discount.
I have a number of speaking engagements schedule for this summer. First up is Bropocalypse 2016 taking place on June 11th and 12th in Sydney, Australia. I’ll be speaking with uber-colleagues Alan Aragon, Bret Contreras, and James Krieger on what will be a terrific weekend of evidence-based learning. Next up is the NSCA National Conference in New Orleans this July, where I’ll speak on loading strategies for maximizing muscular gains. Then comes the CanFitPro World Expo in Toronto, Canada where I’ll be speaking on a number of fitness- and nutrition-related topics, as well as doing a book sign at the expo. Finally, at the end of August I’ll be in Oslo, Norway at the AFPT Fitness Convention along with some of the best and brightest minds in fitness. Last year’s event was a sell-out so if you’re planning to attend book early!
May 29, 2016
Training frequency is one of the most hotly debated topics in the field of resistance training. While traditionally the term frequency has been associated with how many days a week you work out, a potentially more important variable is the number of times a given muscle group is trained per week.
The internet is littered with varying opinions as to optimal training frequency for maximizing muscle hypertrophy. Some preach the typical bodybuilding “bro-split” which involves training each muscle group once a week with high volumes per session, whereas others propose training each muscle as many as 6 days a week with lower per-session volumes is the best way to get jacked. Problem is, all these opinions are largely anecdotal with limited scientific support. Seems hard to believe, but there hasn’t been a whole lot of research on the topic, and the studies that have been carried out have employed a variety of methodological designs that makes it difficult to sort out a conclusion at face value.
In an attempt to achieve better clarity on the effects of frequency on muscle growth, I recently collaborated on a meta-analysis with colleagues James Krieger and Dan Ogborn. In case you’re not aware, a meta-analysis pools data from all studies on a given subject to provide greater statistical power and thus enhance the ability to draw practical inferences.
Here’s the lowdown:
What We Did
A literature search was conducted to locate all studies that directly compared measures of hypertrophy for different weekly lifting frequencies using traditional resistance training programs. Only human studies with healthy subjects were considered, and study duration had to last a minimum of four weeks.
A total of 10 studies were identified that met inclusion criteria. 7 of the studies, comprising a total of 200 subjects, investigated muscle group frequency while the other 3 studies assessed training session frequency when the number of weekly times working a muscle group was matched.
What We Found
We first looked at the effects of frequency as a binary predictor. Simply stated, this means that the higher frequency condition in a study was compared to the lower frequency condition, irrespective of how many days a week the muscle group was trained. Thus, a 2 day-a-week vs 1 day-a-week was treated the same as a 3 day-a-week vs 1 day-a-week. In this model, there was a clear benefit for higher frequency training of a muscle group. The effect size – a measure of the meaningfulness of results – was 48% greater for the higher frequency conditions (0.49 vs 0.30, respectively), translating into an average hypertrophy increase of 6.8% versus 3.7% for higher vs lower frequencies, respectively. Moreover, as shown in the accompanying chart, every study on the topic showed a benefit to training with higher frequencies.
Due to an insufficient number of studies looking at training 1, 2, or 3 days per week, we were unable to produce reliable estimates on the hypertrophic effects of specific lifting frequencies. Similarly, with only 3 studies looking at training session frequency when groups were matched for frequency of training per muscle group, data was insufficient to produce reliable estimates for effects on hypertrophy.
What are the Practical Implications
The primary take-away from the meta-analysis is that there appears to be a pretty clear benefit to training muscle groups with higher weekly frequencies. At the very least, the study shows that training a minimum of 2 days a week is needed to maximize muscle growth. Unfortunately there simply aren’t enough studies to make more concrete determinations as to the precise number of times that a muscle should be trained each week for optimal growth. Nevertheless, training a muscle just once a week was shown to promote substantial muscle growth. So the claims made by some that the typical bro-split only works for juiced-up bodybuilders are patently false.
It’s important to realize that research studies are relatively short-term, usually lasting 6 to 12 weeks. Problem is, you can’t necessarily extrapolate that results found would continue over time. This is particularly true of a variable such as frequency, as high training frequencies may ultimately lead to an overtrained state and thus have a negative impact on muscle development. Given such a possibility, it may be prudent to periodize training frequency, varying the number of times a muscle is trained each week in a systematic fashion. It also indicates a potential benefit to instituting regular deload periods, where a week of reduced frequency, volume, and/or intensity is strategically integrated into your program every month or so to facilitate recuperation and regeneration.
Importantly, remember that research reports the average responses, but there are generally large inter-individual differences in results. Some may respond best to higher frequencies while others might do better with lower frequencies. Use research to guide your programming, then experiment to see what works best for you.
April 16, 2016
I was recently interviewed for an article by Men’s Health Magazine on how to target the lower aspect of the abdomninals. As discussed in the article, there is evidence that you can increase activation of the lower abdominal region by initiating a posterior pelvic tilt during performance of exercises such as the reverse crunch and hanging knee raise. Here is a video depicting proper performance:
Now what isn’t clear is whether the increased activation of the lower abs translates into greater muscle development over time. There is emerging research that muscle growth is correlated to the region of greatest activation, but the evidence is far from conclusive at this point. Taking all things into account, there is a potential benefit to performing targeted lower abdominal exercise for those seeking to maximize development in this region. It probably won’t make much of a meaningful difference for the average gym-goer, but for those who aspire to develop their physique to the utmost (i.e. bodybuilders) it may well provide a tangible benefit.
April 6, 2016
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.
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.
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.
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.
February 14, 2016
Proper manipulation of program variables is essential for maximizing the hypertrophic response to resistance training. Variations in volume, loading and rest intervals all have been shown to impact muscular adaptations.
One variable that hasn’t received as much attention is lifting tempo – i.e. how fast you perform a repetition. When you’re using very heavy loads this is moot; although you’ll necessarily need to try to move the weight quickly, the actual concentric speed will be fairly slow. To illustrate this point, a study by Mookerjee and Ratamess found that the first concentric repetition of a 5RM bench press took 1.2 seconds to complete while the fourth and fifth repetitions took 2.5 and 3.3 seconds, respectively. These findings occurred despite subjects being instructed to perform the reps explosively.
When the loads are lightened, however, you have a lot more control over lifting cadence. A wide range of volitional tempos are possible depending on the magnitude of load. Recommendations on the topic are highly disparate depending on who you listen to. Some fitness pros advocate explosive lifts while others recommend slowing tempo down to where a single repetition takes 45 seconds to complete as seen in this video
In an effort to synthesize the evidence and gain clarity on the issue, I collaborated on a meta-analysis with uber-pros James Krieger and Dan Ogborn. The study titled, Effect of repetition duration during resistance training on muscle hypertrophy: a systematic review and meta-analysis was recently published in the journal, Sports Medicine. In case you’re not aware, a meta-analysis pools data from all studies on a given topic and then statistically quantifies the results to provide a gauge of how meaningful the differences are between conditions.
Here’s the scoop.
What We Did
An extensive search of the literature was carried out for randomized controlled trials that directly compared the effects of different training tempos on muscle hypertrophy in healthy individuals. Studies had to last a minimum of 6 weeks and both groups had to perform reps to the point of momentary concentric muscle failure. A total of 8 studies comprising 204 total subjects ultimately met inclusion criteria – a surprisingly low number for such an important topic.
What We Found
There was no difference in hypertrophy between lifting durations of 2 to 6 seconds when using dynamic constant external resistance (typical free weights and machines). A single study using isokinetic dynamometry showed that durations of a half-second up to 8 seconds produced similar hypertrophy, although the generalizability of this study to traditional training methods is somewhat questionable.
There does seem to be a threshold as to how slow you can go, as evidence suggests that “superslow” lifting (i.e. durations above 10 seconds) is suboptimal for hypertrophy. The research on this topic is limited thereby making it difficult to draw firm conclusions, but a recent study found that a traditional speed group increased muscle cross sectional area by 39% compared to only 11% in a group performing reps at a tempo of 10 seconds up, 4 seconds down. These results held true despite an almost five-fold greater time-under-tension for the superslow group. A follow-up study by the same lab showed satellite cell content and myonuclear domain – important components in the ability to increase muscle mass over time – were substantially greater with traditional compared to superslow training. These findings are consistent with research showing that muscle activation is reduced up to 36% when training at very slow speeds (5 seconds concentric and eccentric). And since maximal hypertrophy is predicated on recruiting the full spectrum of muscle fibers and keeping them stimulated for a sufficient period of time, it is logical to speculate that training in a superslow fashion is inferior if your goal is to optimize muscular gains.
What are the Practical Implications
Current research indicates that a wide range of lifting durations can be used to maximize hypertrophy. Given the limited number of studies and their diverse methodology, however, the topic is far from settled. Based on the evidence it would seem prudent to take no more than about 3 seconds on the concentric portion of the movement. Beyond this cadence, you’d need to reduce the load to a point where it could negatively impact the ability to fully stimulate the highest threshold motor units. Eccentric actions should be performed so that the load is controlled against the forces of gravity; simply letting the weight drop fails to provide sufficient muscular tension for the majority of the action (and it also increases the risk of joint-related injury). As with concentric actions, there does not seem to be any advantage to slowing the movement down to more than about 3 seconds and it is possible that doing so might actually be detrimental to growth. I’d add that the reps should be carried out with sufficient control so that a mind-muscle connection can be established with the target musculature – the current body of evidence suggests that such a strategy is beneficial for maximizing muscle activation, which may in turn lead to greater gains.
I’ll note that the above recommendations are rather liberal, giving the benefit of doubt to somewhat slower tempos. My general feeling is that the concentric portion of a rep should be around 1-2 seconds – the most important thing here is to control of the weight by using an internal focus to visualize the target muscle as you lift. Although results of our meta-analysis showed no “statistically significant” differences in tempos up to 3 secs concentric, data from Tanimoto et al show a substantially greater effect size (a measure of the “meaningfulness” of results) for muscle growth favoring traditional (1 sec on concentric and eccentric – effect size 1.08) vs slower (3 secs concentric and eccentric – effect size 0.74) lifting cadences. It therefore would seem a slightly faster tempo is warranted, at least on multi-joint exercises
Could combining different repetition durations potentially enhance the hypertrophic response to training? It’s impossible to say as no study to date has investigated this possibility. As such, the best advice therefore is to experiment for yourself and see if this may spur additional growth. Remember: the best research often comes from what is learned in the trenches!
February 12, 2016
Wanted to keep you updated on all that is going on at the moment. So much to share!
First and foremost, I’m excited to announce that I have two soon-to-be-released books. One is a consumer book, called Strong and Sculpted, that’s targeted to women who want to optimize muscle development. The book details a complete periodized program to achieve this goal, combining the latest scientific evidence with time-tested experience from the field. The other is a textbook called, Science and Development of Muscle Hypertrophy. This book is the culmination of my professional life to date. It is the first text solely devoted to exploring the science of maximizing muscle growth through regimented exercise. I cover the molecular basis of hypertrophy, the mechanisms, the practical application of resistance training variables, and the different periodization models that can be used to optimize results. There are chapters on the effects of aerobic exercise and nutrition, as well. No stone is left unturned. I couldn’t be more proud of this effort. Both books are available for pre-order by clicking on the highlighted links.
Here’s a vid of the cross cable reverse fly exercise. It’s one of my favorite exercises for targeting the posterior delt. Notice the control throughout both the eccentric and concentric actions, making sure to keep constant tension on the target muscle.
I have numerous speaking engagements scheduled for this year that will take me around the globe. I’m particularly excited about a couple of upcoming events where I’ll share the stage with my esteemed colleagues Alan Aragon, Bret Contreras, and James Krieger. We’ll be speaking at the inaugural Personal Training Collective Annual Conference to be held at the University of Bath in England on April 23 and 24. We next will be speaking in Sydney, Australia at Bropocalypse 2016 taking place on June 11th and 12th. These events are sure to sell out so get your tix early! My travels will also include engagements in Denmark, Norway, Brazil, and New Orleans, with others currently in discussion. I’ll keep you all posted over the coming weeks.
I recently co-authored a paper with Bret Contreras on the “mind-muscle connection” that was published in the current issue of the NSCA Strength and Conditioning Journal. In the paper we lay out evidence that suggests a potential benefit to the approach for maximizing muscle growth. It’s a really interesting topic that needs more research; as such, I have a study planned for later this year that will hopefully shed more light on its efficacy. You can read the full text of the paper, as well as most of my other published works, on my Researchgate page
February 5, 2016
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.
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.
August 23, 2015
In a recent interview for The Fitcast, the host asked whether there was anything I’d change about my book The MAX Muscle Plan. A fair question, no doubt. After all, the book was written over four years ago and our understanding of the science and practice of training continues to evolve. So naturally there were several things that I mentioned in retrospect, most pertinently my views on nutrient timing.
But afterward, it occurred to me that I neglected to bring up an important topic of concern; namely, my use of the ratings of perceived exertion (RPE) scale to gauge training intensity of effort. Now don’t get me wrong; the RPE is a viable tool in this regard. Research shows that It provides a reasonably accurate means to predict 1-RM from submaximal lifting intensities. Fitness professionals have used it extensively for years.
The literature backs up my personal experience on the topic. Since publication of my book, I’ve received a number of emails from readers saying they were confused about the use of the scale. Some stated they found it awkward to integrate into practice. Others felt that terms such as ‘moderate’ ‘hard’ and ‘extremely hard’ were too ambiguous with respect to exercise intensity of effort.
Fortunately, I’ve since come to learn that a more intuitive scale called Reps-to-Failure (RTF) exists. As the name implies, the RTF is based on how many reps you perceive you have left in the tank after completing a set. If you went to all-out failure, the value would be ‘O’ (no reps left in the tank). If you feel you could have gotten an additional rep, the value would be 1; if you could have gotten 2 additional reps you’d be at a ‘2’, etc. I limit the range from 0-4; anything above a 4 is basically a warm-up set. Below is a chart that outlines the particulars of the scale.
The RTF scale has been validated by research. A recent study of competitive male bodybuilders showed a high positive association between estimated RTF and the actual number of repetitions-to-failure achieved. Accuracy was found to improve during the later sets of exercise performance, indicating a rapid learning curve the more the scale is used.
So my recommendation here is to use the RTF scale for gauging lifting intensity; IMO, it’s easier to employ and more accurate than the RPE. If you’re currently using The MAX Muscle Plan simply substitute the RTF value for the RPE in reverse order. Thus, an RTF of ‘0’ corresponds to an RPE of ’10’; an RTF of ‘1’ corresponds to an RPE of ‘9’, etc. It shouldn’t take you more than a few sessions experimenting with the RTF to be thoroughly proficient in its use.
July 17, 2015
Split routines are pretty much synonymous with bodybuilding. A recent survey of 127 competitive bodybuilders found that every respondent trained with a split routine. Every one! Moreover, 2/3 of respondents trained each muscle only once per week (what is popularly known as a “bro-split”) and none worked a muscle more than twice weekly. The theory behind such routines is that growth is maximized by blasting a muscle with multiple exercises from multiple angles and then allowing long periods of recovery.
Things weren’t always this way, though.
Old-school bodybuilders such as Steve Reeves and Reg Park swore by total-body routines, working all the major muscles each and every session over three non-consecutive days-per-week. Proponents thought that the greater training frequency was beneficial to packing on lean mass.
Thing is, the choice to use one type of routine or another has been almost exclusively based on anecdote and tradition. Surprisingly little research has been carried out on the topic, and no study had directly compared muscle growth in a total-body routine versus a bro-split.
My lab carried out a controlled experiment to investigate the effect of training frequency on muscular adaptations. The study was recently published in the Journal of Strength and Conditioning Research. Here’s the scoop.
What We Did
Nineteen young men with an average of more than 4 years lifting experience were randomly assigned to a resistance training program using either a total-body (all muscles worked in a session) or split-body routine (2-3 muscle groups worked per session). The program consisted of 21 different exercises spread out over a 3 day-per-week training cycle. The volume of the routines were matched so that both groups performed an equal number of sets and reps over the course of each week. All subjects performed 3 sets of 8-12RM per exercise. Training was carried out for 8 weeks. The table below shows the program design for both routines.
Subjects were tested pre- and post-study. We used B-mode ultrasound to measure the thickness of the biceps, triceps, and quads, and assessed maximal strength via 1RM for the back squat and bench press. Subjects were advised to consume their normal diets and we monitored food intake by analysis of a self-reported diary.
What We Found
Subjects in both groups significantly increased hypertrophy in the arm and leg muscles. That said, muscle mass increased significantly more in the biceps/brachialis for the group performing total body training compared with those in the split routine group. There was a trend for greater increases in the quads (i.e. vastus lateralis) and the effect size – a measure of the “meaningfulness” of results – markedly favored the total body group. Although no significant between-group differences were found in triceps thickness, the effect size again showed an advantage to total body training.
With respect to strength, both groups significantly increased 1RM performance in the bench press and squat from baseline. There were no significant between-group differences in either of these measures, although the effect size for the bench press did seem to favor the total body group.
How Can You Use This Info?
On the surface it would seem that a total-body routine is superior to a one-muscle-per-week bro-split for building muscle. All of the muscles we investigated showed greater growth from a higher training frequency. For the biceps, these results were “statistically significant,” meaning that that there was a greater than 95% probability that results did not occur by chance. While results in the quads and triceps did not reach “significance,” other statistical measures indicate a pretty clear advantage for the higher frequency routine. These results would seem to be consistent with the time-course of protein synthesis, which lasts approximately 48 hours (there is even some evidence that the time course is truncated as one gains lifting experience). Theoretically, repeated spiking of protein synthesis after it ebbs would result in greater muscular gains over time.
Before you jump the gun and ditch your split, a few things need to be considered when extrapolating results into practice.
First and foremost, it’s important to remember that the study equated volume between conditions. This was done to isolate the effects of frequency on muscular adaptations – an essential strategy for determining causality. However, a primary benefit of a split routine is the ability to increase per-workout volume while affording ample recovery between sessions. Since there is a clear dose-response relationship between volume and hypertrophy, total weekly volume needs to be factored into the equation. Certainly it’s possible that a split routine with a higher weekly volume would have performed as well or even better than the total body routine. Or perhaps not. We simply don’t know based on the current literature.
In addition, the vast majority of subjects in the study reported using a split routine as the basis of their usual workout programs, with muscles worked just once per week. This raises the possibility that the novelty factor of the total body routine influenced results. There is in fact some research showing that muscular adaptations are enhanced when program variables are altered outside of traditional norms. It’s therefore conceivable that participants in the total body group benefited from the unaccustomed stimulus of training more frequently.
Drawing Evidence-Based Conclusions
Given the available info, here’s my take on how the findings can be applied to your training program. There does seem to be a benefit to more frequent training sessions if max muscle is the goal. In this regard, it’s best to directly work each muscle at least twice a week; any less and you’re probably not stimulating protein synthesis frequently enough to optimize hypertrophy. Training each muscle three times a week, at least for periods of time, may provide additional benefits for spurring further gains.
Given the novelty factor, it’s reasonable to speculate that periodizing frequency over the course of a long-term training cycle might be the ideal option. Progressing from periods of working muscles twice to three times per week (and perhaps more) and then cycling back again will conceivably provide a novel stimulus that elicits continued gains. But remember: any discussion of training frequency must take total weekly volume into account. Greater training frequencies (from the standpoint of total training sessions per week) using a split routine can be employed to maximize total weekly volume and thus potentially drive greater hypertrophy over time.
May 9, 2015
It’s a commonly accepted tenet that resistance training adaptations follow a “strength-endurance continuum” whereby lifting heavy loads maximizes strength increases while light load training leads to optimal improvements in local muscle endurance. Conventional wisdom also postulates that at least moderately heavy loads are required for building muscle. General training guidelines proclaim that loads lighter than about 65% 1RM are insufficient to stimulate fast-twitch muscle fibers necessary for growth. The so-called “hypertrophy range” is generally considered to be 6-12 reps/set.
Recent research has challenged these established tenets. It has been proposed that if light loads are lifted to muscular failure, near-maximal recruitment of fast-twitch fibers will occur resulting in muscular adaptations similar to those obtained from training heavy.
A meta-analysis from my lab published last year in the European Journal of Sports Science found substantial increases in muscle strength and hypertrophy following low-load training. However, the magnitude of increases were not as great as that associated with using heavier loads, and a trend for superior gains was in fact shown when lifting weights >65% 1RM. I covered the specifics of this meta-analysis in a previous post.
The caveat: All previous studies employed untrained subjects, raising the possibility that results were attributed to the “newbie effect” that states those new to training build muscle from pretty much any activity — even cardio!
To achieve clarity on the topic, my lab carried out a well-controlled study on the effects of high- versus low-load training using resistance-trained individuals, which was just published in the Journal of Strength and Conditioning Research. Here’s what you need to know.
What We Did
Eighteen young men with an average of more than 3 years lifting experience were randomly assigned to a resistance training program using either moderately heavy loads (8-12RM) or light loads (25-35RM). All other aspects of the program were held constant between groups to isolate the effects of load on muscular adaptations. The program consisted of 3 sets of 7 different exercises targeting the major muscle groups (bench press, shoulder press, lat pulldown, seated pulley row, back squat, leg press, and leg extension). Training was carried out on 3 non-consecutive days-per-week (M, W, F) for 8 weeks.
Testing was conducted pre- and post-study. We used b-mode ultrasound to measure the thickness of the biceps, triceps, and quads. We assessed maximal strength via 1RM for the back squat and bench press. Finally, we measured changes in muscle endurance by having subjects perform the bench press at 50% of their 1RM to volitional failure.
What We Found
Both groups significantly increased lean mass in their biceps, triceps, and quads, but no statistically significant between-group differences were noted in any of these muscles (i.e. both groups had similar muscle growth over the course of the study). On the other hand, the heavy load group showed significantly greater strength increases in the back squat and a trend for greater increases in the bench press compared to the light load condition. Conversely, local muscle endurance was markedly greater for the low-load group.
Reconciling the Data
The primary take-home points from the study are as follows:
• Gains in muscle mass are about the same regardless of repetition range provided training is carried out to muscle failure
• Maximal strength requires the use of heavy loading
• Muscle endurance is best obtained from the use of light loads
To really understand the practical implications of the study, however, we need to look a bit deeper at the results.
The superior strength gains for heavy load training are consistent with the principle of specificity, which effectively states that training adaptations are specific to the imposed demands. No surprise here. From a mechanistic standpoint, the ability to exert maximal force has a high neural component, and the associated neural adaptations appear to be optimized through the use of heavy loads. Previous work from my lab showed that these adaptations exist even at the far left aspect of the strength-endurance continuum, as a powerlifting-type routine (3RM) was found to produce greater strength increases compared to a bodybuilding-style workout (10RM). It also makes intuitive sense that you need to train heavy to “get a feel” for using the maximal loads required to perform a 1RM.
The greater improvements seen in local muscle endurance from light-load training were expected as well. Although the topic hasn’t been well-studied, it stands to reason that low-load training is associated with adaptations specific to enhancing buffering capacity, thereby allowing for the performance of a greater number of submaximal repetitions. Again, a basic application of the principle of specifity.
On the other hand, I readily admit to being surprised by the fact that muscle growth was similar between conditions. While a number of previous studies had shown no differences in gains between light- and heavy-load training, I figured this was due to the “newbie effect.” No way could you build appreciable muscle using 30 reps per set.
Or so I thought.
I’m now a believer.
What’s particularly interesting, though, are the potential implications for how muscle growth actually manifests when training in different loading zones. A previous study from my lab showed that muscle activation was markedly greater when performing reps at 75% 1RM versus 30% 1RM. A follow up study (currently in review) found that the heavy-load superiority for activation held true when training at 80% 1RM versus 50% 1RM as well. Combined, these findings suggest that the recruitment and/or firing frequency in the high-threshold motor units associated with the largest type II fibers is suboptimal when training at low-loads. It therefore can be hypothesized that if muscle growth is indeed similar across loading zones — as found in the current study — hypertrophy from light-load training necessarily must be greater in the type I fibers. Indeed, emerging research out of Russia indicates that this is in fact that case with multiple studies showing that light loads promote greater gains in type I fibers while heavy loads increase type II fiber hypertrophy to a greater extent (Netreva et al 2007; Netreba et al 2009; Netreba et al 2013; Vinogradova et al 2013).
Bottom line: If your goal is to build as much muscle as possible, it seems appropriate to train across the spectrum of loading zones; use lighter loads to target type I fibers and heavier loads to target type IIs. In this way, you ensure maximal development of all fiber types.
An interesting point to keep in mind is that none of the subjects in my study trained with more than 15 reps/set during the course of their usual lifting routines and the majority never went above 10 reps. This raises the possibility that their endurance-oriented type I fibers were underdeveloped in relation to the strength-oriented type II fibers. If so, it’s possible that their type I fibers had a greater capacity for growth, which was realized in those who trained using light loads.
The study had some notable limitations. For one, the training period lasted only 8 weeks; whether results would have diverged over a longer time-frame is undetermined. For another, muscle thickness was measured only at the approximate mid-point of each muscle. Research has shown that muscles often hypertrophy in a non-uniform manner. Thus, it is possible that other aspects (i.e. distal or proximal) of the muscles studied might have differed in their growth response.
A final and important point to consider. While people often dismiss light-loads as being for wimps, nothing could be further from truth. Training to failure with high reps is highly demanding and the associated acidosis extremely uncomfortable. To this end, approximately half the subjects in the low-load group puked during the first week of training and several others experienced nausea and/or light-headedness. Although these issues tended to dissipate as time went by, they nevertheless can negatively affect adherence to the program. If you choose to incorporate light-loads into your program, be prepared for a grueling workout!