June 20, 2012
Sex-based comparison of protein synthesis following resistance exercise.

The title says it all.  Who is better able to recover following resistance training?  The results may surprise you (or even motivate you).

Introduction:  Researchers sought out to see whether men or women have higher rates of protein synthesis during the early (1-5) and late (24-48) hour recovery periods.  In addition to the resistance training, they also gave a dose of whey protein (25g) that is expected to induce maximal muscle protein synthesis.  A secondary aim of this study was to see if the large amount of testosterone released by men post-exercise (10 to 15 times higher in men than women) would have an additive effect on muscle protein synthesis that women would not be able to obtain.

Methods:  Eight men and eight women who were participating in regular physical activity took part in this study.  The bout of exercise was an intense bout with 5 sets of 10 reps at 90% of a persons 10 rep maximum on the leg press as well as 3 sets of 12 reps of leg extensions/leg curls supersets.  Upon finishing this workout, subjects were given 25g of whey protein.

Results:  Starting rates of protein synthesis were similar between men and women.  After exercise, protein synthesis increased in men and women at 1-3 hours and remained elevated at 26-28 hours after with no difference between the sexes.Testosterone was approximately 45 times greater in men than women fifteen minutes after exercise but did not have an effect on muscle protein synthesis more than that of women.

Discussion/Conclusion:  This study shows that there are similar rates of muscle protein synthesis as well as anabolic cellular signaling events between men and women following resistance training plus a 25g dose of whey protein in the earl and late phases of post-exercise recovery.  Even though men had a far greater increase in testosterone than women post-exercise, it was not enough to increase protein synthesis more than women.  Therefore, the anabolic effect of resistance exercise clearly is working through some other mechanism other than spikes in testosterone levels.

My input:  So, men do not have it easier when it comes to weight training anabolic responses.  Both sexes are primed equally for muscle recovery.  The fact that they looked at testosterone comparisons really added to the quality of this study.  It is important to note that the authors are referring to muscle protein synthesis during a recovery phase and not muscle protein synthesis in a long-term muscle building sense.  However, recovery is the first step to adding muscle.

West et al J Appl Physiol. 2012 Jun;112(11):1805-13 

April 12, 2012
That would be whey better than leucine. Supplement companies aren’t going to like me.

Whey protein or leucine post-workout to increase muscle protein synthesis (MPS)?  The Phillips group just published an article trying to answer this question. 

Introduction:  You all are probably aware that ingesting amino acids stimulates an increase in muscle protein synthesis even without resistance training.  Leucine has been toted to best stimulate MPS by activating components of a signalling cascade known as mTOR.  There is still controversy though as to whether or not leucine can enhance MPS following leucine infusion or by simply adding more of it to a post-workout protein drink.  This group previously reported the the optimal dose of protein post-workout to stimulate MPS was 20g and that anything below this is not sufficient and anything above this number (40g) does not increase MPS further.  Therefore, the aim of this study was to see if taking a “sub-optimal” dose of whey (6.25g with approximately 0.75g of leucine) protein and supplementing it with leucine or a mixture of essential amino acids without leucine would have an effect on MPS at rest and after acute resistance training.  This will be compared to a dose of whey (25g with approximately 3.0g of leucine) which is sufficient to induce maximal stimulation of MPS after resistance exercise.

Methods:  Twenty-four adult males were randomized to one of three groups that either ingested a whey protein drink, a leucine drink, or an essential amino acid drink.  Prior to ingestion, the volunteers completed an acute bout of unilateral resistance exercise (knee extensions).  Muscle biopsies were taken at the time of ingestion and at time points 1 hour, 3 hours, and 5 hours post-exercise.

Results:  After whey protein ingestion, blood leucine, branch-chain amino acids, essential amino acids, and total amino acids were all highest as compared to the groups that ingested leucine or EAA (without leucine).  Blood leucine was only higher initially after ingesting the leucine drink but stayed elevated longer by ingesting whey.  Rates of MPS remained increased for 3-5 hours at exercise recovery above those volunteers who did not ingest anything, versus the groups who ingested leucine or the EAA drink.

Discussion:  A dose of whey protein that has been previously shown to be less than maximally effective to stimulate MPS after resistance exercise, when supplemented with leucine, resulted in an early (1-3 hour post-exercise recovery) increase in rates of MPS equal to that of ingesting 25g of whey.  Also, the same was found by supplementing a low dose of whey with essential amino acids void of leucine.  However, MPS was sustained longer (3-5 hours post-exercise) only with the group that ingested whey protein.  These differences occurred despite the fact that blood amino acid levels returned to baseline after 3-5 hours but MPS still continued.  Therefore, the authors state that peak activation of MPS does not appear to be driven by increasing leucine in the blood and that amino acid transport across the sarcolemma (plasma membrance of the muscle cell) and intracellular amino acid availability may be important in the regulation of MPS.

Conclusion:  Leucine stimulates MPS post-exercise equal to that of whey protein, despite only containing 45% of the total EAA content of the whey.  However, similar increases in MPS were observed in the EAA ingestion group that did not contain leucine.  Thus, the authors speculate that in young healthy individuals, the leucine content provided by approximately 6.25g (approximately 0.75g of leucine) of whey protein seems adequate to maximally stimulate MPS if sufficient amounts if the other EAA are provided (approximately 8.5g EAA).  Also, the whey protein ingestion group was the only group that sustained MPS 3-5 hours post-exercise.

My input/practicality:  What if I were to tell you I can make a 1lb bag of whey protein last me 3 months?   Well I can, and I do, and I’ve been doing it for years.  I only use a half scoop of whey protein post-exercise.  Never a full scoop.  Never a “heaping” scoop.  Why do you even think they use the word heaping? It’s all about the dolla dolla bill y’all.  This study shows that only 6.25g of whey is necessary to maximally stimulate protein synthesis as long as it contains approximately 750mg of leucine and 8.5g of the other 8 essential amino acids (which are histidine, isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine).  Make sure you check on the labels of your favorite whey protein because it usually lists the amount of leucine and the other essential amino acids on it.  One scoop of whey is usually on average around 20g of protein so if you use a half scoop like me it is around 10g (still a little over from what this study suggests).  Supplement companies are going to hate this study (like they read them anyways) as well as me for posting this but you’ll love it/me for saving you money.

Churchward-Venne et al J Physiol. 2012 Mar 25.

January 5, 2012
Blood Flow Occlusion Training

I got this question from Chris a few months back and was hesitant to answer it quickly (sorry Chris) because, like him, I was skeptical on the studies and waiting for something new to be published.  Well something just came up last month from a review in MSSE. 

Intro: Chris wanted to know what I thought about Blood Flow Occlusion Training, which is simply putting a band (similar to when you get your blood pressure measured) around a working muscle group in order to restrict the blood flow in hopes of increasing protein synthesis in that area.  It sounds crazy to work, right?

Results: Well researchers report that at low intensities (20%-50% of one rep maximum) plus the occlusion, you can get a similar increase in muscle size and strength as traditional, high-intensity resistance exercise.  The group that wrote this review reported a 46% increase in muscle protein synthesis after an acute bout of resistance exercise with occlusion, similar to that as standard high-intensity resistance exercise.  They also reported this muscle protein synthesis was coupled to activation of mTOR (specifically complex 1), which is a protein associated with activation of protein synthesis.

Discussion/How it works:  When you restrict blood flow to an area the body compensates by increasing the strength of blood flow to that limb.  Eventually, the area will build up metabolites from the exercise that cannot be taken away due to venous flow being occluded.  It is thought that this is the reason/stress that creates the internal environment in the working muscle that can create the response of increases in protein synthesis.  For the molecular junkies, scientists add that occlusion training also decreases proteolytic (breakdown) genes FOXO3A, atrogin, and MuRF-1 8 hours after exercise.  However, there were no reported differences in genes between conventional resistance exercise and bloodflow restricted 3 hours post-exercise.

Conclusion:  At this point, the authors suggest that there are still no explanation for the exact cellular mechanisms responsible for the increases in muscle growth following blood flow restriction training.  All that can be said is that it is showing promise in similar increases in mTORC1 in that of conventional resistance training methods.

My input:  Am I going to try it? Probably not.  Even if it works it is still not shown to be better than standard resistance training protocols.  If I were to prescribe this, I would do so to healthy older individuals (age 50 or above) who simply cannot handle the weights of people in their physiological prime since this method has weight intensities of 20-50% 1RM.