Recent Blog Posts

Exercise, Hypertrophy

July 23, 2014

How long should you rest between sets for hypertrophy?

Recently, I collaborated with my friend and colleague, Menno Henselmans, to review the literature on the effects of rest interval length on muscle growth. I’m pleased to report that this review has just been published in the prestigious journal, Sports Medicine. If you’re into the science of hypertrophy, I encourage you to read the paper as we delve into all the relevant research on the topic. In the meantime, here is an overview of the take-aways with practical implications.

General resistance training guidelines recommend that rest intervals should remain relatively short to maximize hypertrophy. In a previous review, The Mechanisms of Muscle Hypertrophy and Their Application to Resistance Training I echoed these sentiments, suggesting that rest periods of 60-90 seconds would seemingly provide an optimal balance between mechanical tension and metabolic stress (primary mechanisms in the hypertrophic response) to enhance anabolism. It should be noted, however, that these recommendations were based primarily on a logical extrapolation of mechanistic data; there simply have not been a sufficient number of studies that have investigated the topic in a well-controlled fashion.

In what is the most comprehensive study on the topic to date Ahtiainen et al. found no differences in muscle cross sectional area between 2 versus 5 minute rest periods in a sample of well-trained men. The study had several strengths including a randomized crossover design (which substantially increases statistical power), the inclusion of experienced trainees, and the use of the gold-standard imaging modality, MRI, to measure muscle growth. The one issue here is that the 2-minute rest period employed by the researchers is longer than what is generally advised for hypertrophy-type training. The impact on metabolic stress diminishes with longer rest periods, and this conceivably could have had negatively affected anabolic signaling in this study.

The other study of note that attempted to investigate the effects of rest interval length on hypertrophy was carried out by Buresh et al, whereby 12 untrained individuals performed their workout with either 1 or 2.5 minutes rest between sets. This study actually showed superior results for hypertrophy in the arms and a trend for greater growth in the legs in the subjects using longer intra-set rest intervals. While these results may seem compelling, it should be noted that muscle cross sectional area was determined by anthropometric means (i.e. surface measurements) which can be quite unreliable and thus compromise accuracy. Further confounding matters is the small number of subjects (only 6 in each group) and the fact that subjects were inexperienced with resistive exercise. Thus, while the findings here are interesting they must be interpreted with caution.

So what practical applications can we derive from the literature? Based on current research, it seems highly doubtful that rest interval length has a substantial effect on muscle growth. Bottom line: It would appear that you can self-select a rest period that allows you to exert the needed effort into your next set without compromising hypertrophic results.

That said, the paucity of controlled studies on the topic make it difficult to draw concrete conclusions. Certainly we know that shortening the duration of rest between sets increases metabolic stress, which is known to stimulate muscle remodeling. We also know that well-trained individuals such as bodybuilders are able to sustain a high percentage of their repetition maximum with rest periods as short as a minute. Could the combination of these factors may provide an additional hypertrophic stimulus — albeit a small effect — over time in well-trained subjects? Could other factors such as increased hypoxia and cell swelling also contribute to such a response?

These are questions that require further research. I’m currently in the process of carrying out a study that will provide relevant answers. I hope to begin data collection before the year is out. Stay tuned.

Henselmans M, Schoenfeld BJ. The Effect of Inter-Set Rest Intervals on Resistance Exercise-Induced Muscle Hypertrophy. Sports Med. 2014 Jul 22. [Epub ahead of print]

Exercise, Studies

July 6, 2014

Can you target different aspects of the hamstrings?

In this post I want to delve into the specifics of a study I recently published in the Journal of Strength and Conditioning Research that investigated muscle activation in two popular hamstrings exercises: the stiff leg deadlift and the lying leg curl. While other studies have evaluated differences between these exercises in activation of the medial hamstrings (semitendinosus and semimembranosus) versus the lateral hamstrings (biceps femoris), our study is unique in that we also looked at activity in the upper and lower aspects of the individual muscles.

My interest in undertaking this work revolves around an emerging body of research showing that, contrary to popular belief, muscle fibers do not necessarily span from origin to insertion. Rather, many muscles are compartmentalized so that fibers terminate intrafascicularly (within the fascicle) with each subdivision innervated by its own nerve branch. This structure provides a mechanism by which different exercises can conceivably target different portions of a given muscle. It just so happens that several studies have shown that the hamstrings muscles are in fact partitioned in a manner that would potentially allow for such regional-specific activation. I thus decided to test this hyptothesis in the lab under controlled conditions.

What We Did
Ten young men were recruited to participate in the study. All of the subjects were experienced with resistance training, defined as lifting at least 3 times per week for a year or more. We employed a counter-balanced design where each subject performed both the stiff-leg deadlift and the leg curl. This design provides a high-degree of statistical power, thereby improving the possibility of detecting a significant difference if one in fact does exist. Testing took place over two sessions. In the first session we tested subject’s 8RM on both exercises. The second session involved assessing activation during performance of the movements at the subject’s 8RM.

Muscle activation was determined by a technique called electromyography (EMG). Electrodes were placed on the upper and lower aspects of the subject’s medial and lateral hamstrings; care was taken in placement to make sure that cross-talk between muscles did not confound results. The subjects then performed one of the exercises followed by a lengthy rest period and then performed the other exercise. The exercises were counterbalanced so that Subject 1 performed the leg curl first, Subject 2 performed the stiff-leg deadlift first, etc. This ensured that the order of performance did not confound results. All sets were performed at the subject’s 8RM to muscular failure.

What We Found
Activation of the upper hamstrings was similar between exercises. Interestingly, however, activation of the lower hamstrings, both medially and laterally, was significantly greater in the lying leg curl. The differences in activation of the lower hamstrings was stark, with the leg curl showing greater lower lateral hamstrings activity of ~170% and lower medial hamstrings activity of ~65% compared to the stiff-leg deadlift. The data for the lateral hamstrings was not unexpected; the short head of the biceps femoris does not cross the hip joint, so a knee-dominant exercise such as the leg curl would necessarily be the only way to directly target this muscle. However, the data for the medial hamstrings was somewhat surprising since both the semitendinosus and semimembranosus are biarticular muscles. Results suggest that the partitioning of these muscles may allow for greater regional-specific activation in their lower aspect.

Practical Implications
The findings suggest that performing both a hip-dominant hamstrings exercise (such as the stiff-leg deadlift) and a knee-dominant exercise (such as the leg curl) are beneficial to maximize activation of the muscle complex. Given that muscle hypertrophy is predicated on recruiting as many motor units as possible in the target muscles and achieving high firing rates in these motor units for a sufficient length of time to fully stimulate the fibers, it stands to reason that greater activation achieved should lead to greater regional-specific muscle growth. Several recent studies have in fact shown this to be the case, with non-uniform hypertrophy correlating to the region of greatest muscle activation. However, the evidence to date remains correlational and more research is needed to draw cause-effect conclusions. In the meantime, the present study provides interesting insight into how different exercises elicit different responses in a given muscle and lends support to the potential benefits of varying exercise selection to optimize muscle development.

Schoenfeld BJ, Contreras B, Tiryaki-Sonmez G, Wilson JM, Kolber MJ, Peterson MD. Regional Differences in Muscle Activation During Hamstrings Exercise. J Strength Cond Res. 2014 Jun 24. [Epub ahead of print]


May 24, 2014

Debunking the Myth of Functional Exercises

You pretty much can’t pick up a fitness magazine these days without seeing an article on “functional fitness.” The promotion of the “functional fitness” concept was basically a reaction to popular bodybuilding-type programs that focused on structuring workouts by muscle groups such as the chest, back, shoulders, and legs. Functional fitness proponents countered that such routines did not address the complex interaction between muscles during human movement, leading to the catch-phrase: “Train movements, not muscles.”

On the surface the premise sounds logical.

In reality it’s a gross oversimplification of motor learning principles.

As I’ve previously written about, functional transfer through exercise exists on a continuum. Bottom line is that we need to stop thinking about exercises as “functional” or “non-functional” and realize that for most practical purposes all exercises can produce functional improvements depending on task requirements and the individual.

In this video, Bret Contreras and I discuss the nuances of functional training. We review the science on the topic, dispel some of the popular myths, and delve into practical applications for exercise selection.


May 16, 2014

Building a Better CrossFit

CrossFit is perhaps the biggest (relatively) new thing in fitness. With over 7,000 gyms worldwide and more than 10 million participants, it’s an understatement to say that CrossFit is big business.

When it comes to CrossFit training methods, everyone seems to have an opinion. Thing is, opinions are rarely neutral; people invariably either hail it as the ultimate fitness experience or trash it as cultist pseudo-science.

As with most things in life, the truth lies somewhere in between.

Without question, CrossFit has positive attributes. If nothing else, it fosters a sense of camaraderie amongst participants. CrossFitters feel like they’re part of a fitness community. The focus on competition pushes them to be their best. Exercise becomes fun. Not surprisingly, adherence in CrossFit gyms tends to be much better than in traditional resistance training programs. Remember: The best workout routine is the one that you’re able to stick with.

And despite what some claim, there is nothing inherently wrong with the CrossFit training model. Is it going to maximize your muscular strength or hypertrophy? No. But it is a viable strategy for improving overall fitness. Depending on your current fitness level, you’ll generally get stronger and bigger from CrossFitting, and you’ll almost certainly improve your muscular endurance. Moreover, when combined with proper nutritional programming, it can help to expedite the loss of body fat. In other words, for a large segment of the population, the CrossFit model has applicability.

The real “issue” is not with the concept of CrossFit per se, but rather in the way that many facilities carry out its training practices. So let’s not throw the baby out with the bathwater. Here are three ways to take the basic principles of CrossFit and enhance its effectiveness and safety.

Planes of movement
Vary Planes of Movement: The human body is designed to move in three-dimensional space. To facilitate such movement, the musculoskeletal system is able to call upon different muscles based on the directional requirements of a given task. The problem with most CrossFit gyms is that almost all exercises are carried out in the sagittal plane. This ultimately results in strength imbalances between agonist and antagonist muscles that not only has a negative impact on your appearance, but can also hasten the onset of injury. Case in point: I recently conducted a study that investigated muscle activation in the rear delt fly – a transverse plane exercise. Guess which subject was the weakest in this movement? Yep, a CrossFitter. When questioned about his training practices, the subject stated that he never performed any horizontal abduction exercises. The result: poor posterior deltoid development. Here’s the easy fix: adopt a multi-planar approach to training by including exercises for all three cardinal planes (sagittal, frontal and transverse) in your routines. This will help ensure you achieve balance and symmetry between muscle groups, and reduce the possibility of incurring any structural discrepancies.

Periodize Volume and Intensity of Effort: CrossFit training is generally an all-out endeavor; you go balls-to-the-wall each and every session, pushing yourself until you can’t push any more. Bad idea. Sure, high workout volumes and failure training can help to enhance muscular adaptations. But perpetually testing your physical limits over and over again is destined to lead to an overtrained state. The body simply isn’t made to endure such extreme repetitive efforts. Preliminary work from my lab shows that CrossFitters display a much greater incidence of symptoms related to overtraining compared to those who use traditional lifting practices. They report higher levels of fatigue, reductions in performance, issues with sleeping, and incidences of illness. The upshot is a training plateau and even regression of results. The solution: employ periodization principles so that volume and effort are systematically varied over time. This can include gradually increasing volume throughout the course of a training cycle, incorporating a step-loading approach so that weights get progressively heavier on a week-to-week basis, and/or interspersing “deload” weeks where both the volume and intensity of training are reduced. These types of practices will allow for the necessary restoration and recuperation of the body’s resources, facilitating continued progress.

Focus on Form : Perhaps the biggest issue with CrossFit training practices is the focus is on doing as much work as possible as quickly as possible any way possible. There’s certainly nothing wrong with trying to pack more exercise into less time; this is a viable strategy for enhancing metabolic adaptations. It’s the “any way possible” aspect that causes problems. Potentially big problems. The lifting technique employed at many CrossFit gyms is nothing short of atrocious. Just check out the above video for proof. It’s therefore no wonder that the incidence of injuries is reported to be high amongst CrossFitters. The solution here should be obvious; don’t sacrifice proper form at the expense of exercise quantity. Make sure you have the technique to each exercise down pat so that it is ingrained in your subconscious. If necessary, regress in your exercises before you progress. This is particularly true with complex movements such as the Olympic lifts, where the potential for injury is high. Remember that safety is paramount to any routine; an injury is bound to derail your efforts.

Exercise, Hypertrophy

April 11, 2014

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

Exercise, Hypertrophy

March 8, 2014

Does Blood Flow Restriction Increase Muscle When Combined With Traditional Resistance Training?

Blood flow restriction (BFR) training is an emerging technique that consistently has been shown to improve muscle strength and size in a variety of populations. If you are not familiar with BFR, you can read my recent T-Nation article that details the hows and why’s of the topic. If you’re interested in the research, you can read the review that I co-authored here.

A new BFR study by Luebbers et al. has been creating a lot of buzz. A number of people have emailed me to ask my opinion on the paper, so I figured it was worthy of a blog post.

Briefly, the study was a follow up to a previous study by Yamanaka et al. , who reported significant increases in chest girth, as well as 1RM bench press and squat performance when BFR was combined with heavy resistance training in a group of well-trained college football players. Here are the particulars of the new study followed by my commentary and take home points.

Study Design:
The study used a protocol similar to the investigation carried out by Yamanaka et al. Sixty-two Division 2 football players took part in the study during their off-season from competition. Subjects were randomized into 1 of 4 groups:
• H/S/R Group. This group performed high-intensity training (H) consisting of traditional strength training exercises (bench press, overhead press, power cleans, squats, etc) and auxiliary lifts (bicep curls, triceps extensions, calf raises, and abdominal work). In addition, they performed supplemental lifts (S) at the end of each workout consisting of 4 additional sets of bench press on upper body day and 4 additional sets of squats on lower body day. The supplemental work was carried out under blood flow restriction (R).
• H/S Group. This group performed the exact workout as H/S/R except no BFR was used for the supplemental exercises.
• H Group: This group completed only the basic high-intensity training routine (H). They performed no supplemental exercise with or without BFR.
• M/S/R Group. This group performed only the auxiliary exercises but not the traditional strength training exercises. They also performed supplemental work with BFR at the end of each workout.

The BFR was a “practical” protocol that employed ~3 inch elastic wraps to occlude flow. The load for these exercises was set at 20% 1RM with the first set consisting of 30 reps followed by 3 sets of 20 reps separated by 45 seconds rest. For all groups, the training program employed an upper/lower body split performed 4 days per week for 7 weeks. The split followed a 2-on/1 off, 2-on/2-off format with workouts taking place Monday, Tuesday, Thursday, and Friday.

The Results
At the end of the 7 week study period, the group performing the traditional strength training protocol supplemented with BFR (H/S/R) showed significantly greater increases in 1RM squat compared to the other groups but there were no differences in 1 RM bench press between groups nor were there any differences in thigh, chest, or arm girth.

The researchers should be commended for an ambitious study design. They had a fairly large sample size (over 60 subjects) and the 4 groups provided diverse info on a variety of possible program applications. Moreover, the subjects were all well-trained lifters (average of over 7 years resistance training experience), which rules out any confounding issues associated with an initial learning curve and inflated gains from sedentarism.

That said, the study had a number of substantial limitations that cloud the ability to draw relevant conclusions. First and foremost, the use of circumference measurements as a proxy for muscular gains is highly suspect as the technique does not specifically measure muscle tissue in isolated areas of the body. Indeed, imaging techniques such as ultrasound have been shown to detect increases in muscle hypertrophy not seen by measures of girth. Compounding matters, the researchers made no attempt to control for nutrition. Remember, the subjects were college football players in the offseason from competition. To put it mildly, it’s highly unlikely they weighed their food and adhered to a balanced nutritional regimen. Since girth measurements cannot discern between muscle tissue and subcutaneous fat, this certainly could have confounded results.

Another thing that jumped out at me when reading the methodology was the following statement: “All sessions were supervised by the same two primary researchers in order to ensure compliance.” The study had over 60 subjects who trained at one of three times during each training day. That means that there were over 20 subjects training at a given time. How can two researchers adequately supervise all these subjects and ensure that they are training as per protocol? In my lab, I have a dedicated research assistant work with each subject in a training study. They supervise every aspect of the workout protocol – from using proper technique, to exerting sufficient intensity of effort, to making sure that the rest intervals are rigidly upheld. If research assistants did not in fact help out with supervision here, I’d have to question how well subjects actually complied with the protocol.

Finally and importantly, the results don’t make a whole lot of sense. Specifically, how could lower body strength show greater increases with BFR without concomitantly greater increases in hypertrophy? There are two primary mechanisms for strength improvements: an increase in muscle size (there is a direct relationship between muscle cross sectional area and the ability to produce force) and/or an enhancement in neural response. Research indicates that neural enhancement is primarily achieved through the use of heavy loads, particularly in a well-trained population who have transitioned past the initial motor learning stage. Thus, I find it difficult to believe that BFR — which uses very light loads — had a significant impact on neural aspects such as rate coding or synchronization. If strength was significantly increased in the BFR group compared to the non-BFR groups, it would seem that these improvements would have to be due to greater gains in muscle mass.

Bottom Line
While this study (as well as the previous study by Yamanka et al.) provides interesting data on the potential use of BFR as an adjunct to traditional resistance training, the aforementioned limitations make it difficult to draw an practical conclusions. Similar studies should be carried out using a validated imaging technique (i.e. MRI, CT, ultrasound, etc) under well-supervised conditions to determine if there are in fact any benefits to combining BFR with heavy loads.

Exercise, Hypertrophy

February 3, 2014

New Study: Bodybuilding-Type Training Increases Intracellular Water Content

I recently co-authored a new study that investigated increases in intracellular hydration following performance of 16 weeks of bodybuilding-type resistance training. I am pleased to say that the study — a collaboration with colleagues at Londrina State University in Brazil — has just been published in the European Journal of Sports Science. Here is a summary and what to take home from the findings.

The Background:
It has been well-established that regimented resistance training results in increases in muscle hypertrophy (i.e. growth). The mechanical forces associated with lifting cause an adaptive response that results in increases in the contractile elements (actin and myosin) as well as structural proteins of muscle. These adaptations ultimately facilitate the muscle to be able to exert greater amounts of force. It’s a basic adaptive response to a stress (i.e. a survival mechanism) that makes us stronger so we can handle similar future events if and when needed.

There has been extensive debate as to whether resistance training also increases non-contractile (sarcoplasmic) hypertrophy. Non-contractile elements include things such as collagen, organelles, and fluid. The fluid component is one of the more intriguing areas of discussion. It’s no secret that resistance training can have an effect on altering intramuscular water — the “pump” is a well-known phenomenon in bodybuilding-type training. But what remains unclear is whether resistance training can increase intracellular water chronically over time. Our study sought to shed light on this topic.

What We Did:
A total of 64 college-aged subjects (30 men and 34 women) participated in the study. Subjects engaged in a supervised progressive resistance training program carried out 3 non-consecutive days a week over 16 weeks. Training consisted of a bodybuilding-type routine whereby 3 sets of 8-12 reps were performed with 60-90 seconds rest between sets. A total of 11 exercises were performed per session using a combination of free weights, cables, and machines. All sets were taken to the point of momentary muscular failure.

Bioelectrical impedance spectroscopy (BIS) was used to measure total body water, intracellular water and extracellular water content. BIS is a validated tool for measuring body water and its various sub-fractions. Assessments were made at baseline, the mid-point of the study, and at study’s end.

The Results:
Intracellular water was significantly increased following training in both men and women. The effect size — in simple terms, a measure of the magnitude of results that takes into account variance between subjects — was considered moderate, indicating the results are meaningful. Both men and women showed approximately equal responses as to increases in intracellular water over the course of the study.

Practical Implications:
As noted, this study provides compelling evidence that regular bodybuilding-type resistance training leads to a chronic increase in intracellular fluid status. Why should anyone care about increasing the water content of muscle? Well, there is a large body of research showing that cell swelling via increased intracellular hydration results in marked increases in protein synthesis and reductions in protein degradation; a hypertrophy homerun. These findings have been shown in a wide variety of cell types, implying that keeping muscle fibers hydrated may actually increase contractile hypertrophy and thus enhance strength.

Now it’s important to note that these observations are from in vitro (i.e. test tube) data. Whether similar results play out in practice in hard-training lifters is still unknown and need further study. That said, the aforementioned findings certainly suggest that there may well be an anabolic effect (and in fact one of the hypotheses for hypertrophic effects of creatine is its role as an osmolyte).

What remains unclear is whether the increased intracellular hydration is specific to bodybuilding-type training or inherent with all types of lifting. We speculated that results of the current study may have been due to increased glycogen storage. Bodybuilding-type training relies primarily on fast glycolysis to fuel performance, whereby carbohydrate is the primary energy source (as opposed to powerlifting-type training, which relies primarily on the phosphagen system). As such, the body adapts by increasing its capacity to store glycogen. Since glycogen attracts 3 grams of water for every glycogen granule, it stands to reason that this was responsible for the increased hydration status.

What’s Next:
We are currently designing a study that will compare chronic changes in water sub-fractions following bodybuilding- versus powerlifting-type training. The hope is to begin data collection before the year is out. Stay tuned.

Ribeiro AS, Avelar A, Schoenfeld BJ, Ritti Dias RM, Altimari LR, Cyrino ES. Resistance training promotes increase in intracellular hydration in men and women. Eur J Sport Sci. 2014 Jan 28. [Epub ahead of print]


November 3, 2013

How Important is Exercise Variety?

Some fitness pros claim getting big simply is simply a matter of performing a few “big lifts.” While there’s no question this will pack on size, it’s not enough if your goal is to maximize muscle mass. In this episode of the B&B Connection, Bret Contreras and I discuss the importance of variety in a lifting routine. We separate the science fromt he bro-science, and discuss the practical implications for exercise program design. The webcast includes a discussion on topics such as functional differentiation of muscles, muscle fiber compartmentalization, planes of movement, active insufficiency, varying training angles, and other aspects that go into forming a well-rounded muscle-building routine. As always, we welcome your feedback. Enjoy!

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October 24, 2013

Periodization in Resistance Training

In this latest episode of the B&B Connection, Bret and I discuss periodization and its relevancy to resistance training. In case you don’t know, periodization can be defined as the planned manipulation of exercise program variables (in this case sets, reps, load, etc) to optimize a given fitness component. Despite what you may have heard, research on periodization is highly conflicting. Here we discuss the limitations of the researh, delve into what can be gleaned from science as well as experience, and provide opinions for practical application of periodized principles. Hopefully it provokes thought and debate on the topic. Enjoy!

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August 25, 2012

This and That…

1) Happy to say that I’m entering the final year of my PhD program at Rocky Mountain University. So far it’s been an extremely rewarding experience. Sure, the coursework has been a bit overwhelming at times, but I’ve become a much more astute fitness professional as a result–particularly in my ability to assess and scrutinize research. Very much looking forward to carrying out my dissertational research and furthering our understanding about the mechanisms of muscle hypertrophy and their application to resistance training.

2) I recently collaborated with my good friend Bret Contreras on another T-Nation article, this one focusing on the Weider Principles. In case you don’t know, the Weider Principles are a set of exercise guidelines compiled by Joe Weider, who built a fitness empire that includes many of the popular fitness magazines and bodybuilding contests. Joe has been maligned by many in the field (and in some cases rightly so) for perpetrating a variety of exercise and nutritional myths. But Joe was a visionary and in our article, 6 Lessons Learned from the Master Blaster we objectively delve into recent research that has validated a number of Joe’s principles and provide recommendations for practical application of the relevant principles.

3) Speaking of Bret Contreras, he has teamed up with physical therapist Jonathan Fass for a new podcast venture called, The Strength of Evidence. It’s a really great listen filled with top-notch info from two really smart guys.

4) Here is a video clip from my lecture at the recent Fitness Education Institute conference in New York City. In this clip, I discuss the importance of adopting an evidence-based approach to training. Many people have a misconception as to what “evidence-based practice” really entails, and here I clarify its meaning and discuss why it is so vital to optimal fitness results.

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5) My new book, The MAX Muscle Plan is set to be released next month. The book details a six month periodized routine designed to maximize muscle development, providing both the scientific basis of how muscles grow as well as detailing every exercise, set and rep of the program. I’m really pumped (no pun intended!) for its release. Much more on this over the coming weeks.

That’s all for now…