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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.

Reference:
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]


Uncategorized

December 28, 2013


This and That…

As 2013 comes to an end, here are some random thoughts and goings on that I’d like to share:

• First and foremost, I’ll be defending my doctoral dissertation in a matter of weeks. The defense will mark the culmination of years of study and research. My dissertation paper titled, “Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men,” was submitted last week for peer-review. I’ll have lots more to say about the results in short order. Looking forward to completing this phase of my education and excited to enter the next phase in my never-ending quest for knowledge and enlightenment in exercise science.

• I was disappointed, although not entirely surprised, that Dr. John Ivy did not respond to my offer to publish a rebuttal to my critique of his recent review on nutrient timing. As discussed in my critique, the review by Dr. Ivy was a classic case of cherry-picking research to support a closely-held opinion while conveniently neglecting to mention compelling evidence to the contrary. This type of article would be expected in the muscle rags, not in a peer-reviewed journal. If Dr. Ivy truly believes the evidence supports his position, I challenge him to debate me on the topic. He can pick the time and place. Let’s put all the info out there and allow the public to decide. It’s how science is supposed to work.

• Speaking of nutrient timing, I was interviewed by Carl Lanore on Super Human Radio about my recent paper, The effect of protein timing on muscle strength and hypertrophy: a meta-analysis. Carl always does a superb job asking the right questions and allowing leeway for scientific discussion. Some very important info discussed here, not just about nutrient timing, but also as to how to put research into proper perspective for practical decision-making. Here is a link to the interview.

• I’ve had several peer-reviewed papers either published or accepted for publication within the past few weeks. My paper co-authored with Bret Contreras titled The Muscle Pump: Potential Mechanisms and Applications for Enhancing Hypertrophic Adaptations was just published ahead-of-print in the Strength and Conditioning Journal. This article discusses how cell swelling associated with resistance exercise can provide an anabolic stimulus that potentially increases muscle growth. On a related topic, I just received acceptance from the European Journal of Sports Science on a study that I collaborated on with researchers from Brazil showing that bodybuilding-type resistance exercise results in a long-term increase in cellular hydration. This has important potential implications for muscle growth. Finally, another article I co-authored with Bret, Is Postexercise Muscle Soreness a Valid Indicator of Muscular Adaptations? has been made available to be viewed for free by the NSCA. Normally articles published in the Strength and Conditioning Journal are only viewable at no charge for members. I’m not sure how much longer the opportunity will last, so if you haven’t read the article as yet I’d encourage you to download it now.

• Last but not least, here is Episode 7 of the B&B webcast covering evidence-based fitness prescription. Contrary to popular belief, evidence-based practice is not simply a matter of knowing the research; it involves synthesizing the current body of evidence and then combining this knowledge with personal experience and taking the needs and abilities of the individual into account. In this episode we delve into the topic in depth and discuss how to blend the science and art of fitness to optimize training programs.

That’s all for now. 2013 has been a great year, but 2014 should be even better. Look forward to making a meaningful contribution to our understanding of the science and art of fitness and nutrition, and of course sharing that knowledge with you all.

Stay well and stay fit!

Brad