|FSR ≠ more muscle = no news for ya!|
UPDATE: There is new data that extends the results of the study at hand and indicates that there is a link between MPS and muscle gains, after the initial adapation response to exercise.And yes, practically speaking these findings imply that we have to question the real world significance of all the neat studies on the "superior muscle building effects" of whey protein, BCAAs and even more so leucine, in which the authors base their recommendations on acute increases in post-exercise protein synthesis.
Don't worry, you have not been "wheysting" your money: While there is a paucity of data to confirm the long(er) term muscle building effects of isolated amino acids (EAA, BCAA and leucine), there is plenty of data from 6-12 week human trials to support the pro-anabolic effects of whey protein. What we don't have, though is evidence to support the notion that the long-term muscle building effects are as superior to those of other protein sources (e.g. casein) as the increases in acute protein synthesis would suggest.In the corresponding experiment that was funded by the National Science and Engineering Research Council (NSERC) of Canada Cameron J. Mitchell et al. determined whether the acute myofibrillar protein synthesis measured acutely in training-naive subjects after their first bout of resistance exercise with protein consumption would correlate with the actual increase in muscle size after 16 weeks of resistance training.
|Suggested read: "Protein Intake & Muscle Catabolism: Fasting Gnaws on Your Muscle Tissue and Abundance Causes Wastefulness " | more|
After all baseline measurements (including baseline muscle protein synthesis) were recorded, the subjects completed 16 weeks of RT while ingesting a protein rich beverage (30g of the same whey protein of which Burd et al. showed in 2012 that it elicits a higher increase in MPS than casein) immediately after their exercise session and with breakfast on non-training days.
"Briefly, participants trained four times weekly with two upper and two lower body workouts. Lower body exercises are described above in the acute exercise session. Upper body exercises consisted of chest press, shoulder press, seated row, lat pulldown, bicep curl and tricep extension. The program was progressive in linear manner moving from 3 sets of 12 repetitions to 4 sets of 6 repetitions. At the end of the training period, MRI, DXA scans and strength testing were repeated." (Mitchell. 2014)If you look at the above description of the workout (and supplementation regimen) you will probably agree that this is pretty much what the majority of resistance physique oriented gym-goers do.
|Figure 1: Myofibrillar fractional protein synthesis rate (left) measured acutely after a single workout and changes in muscle volume (%) over the whole 16-week study period as a function of the 1-6h post-workout FSR (Mitchell. 2014).|
|Figure 2: Changes in muscle volume (%) expressed relative to acute increases in 4E-BP (Mitchell. 2014).|
After thinking about the implications of these findings for a minute, I do yet have to admit that the assumption that this would refute the previously invoked recommendations completely, is probably premature.
- Burd, Nicholas A., et al. "Greater stimulation of myofibrillar protein synthesis with ingestion of whey protein isolate v. micellar casein at rest and after resistance exercise in elderly men." British Journal of Nutrition 108.06 (2012): 958-962.
- Mitchell, Cameron J., et al. "Acute post-exercise myofibrillar protein synthesis is not correlated with resistance training-induced muscle hypertrophy in young men." PLoS One 9.2 (2014): e89431.