|Intra-workout BCAA supplements are marketed specifically to resistance trainees. If they do have anti-catabolic effects, though, those are - just like potential fatigue reducing effects - significantly more likely to occur in endurance trainees.|
The study, which measured the amount of amino acids directly and does thus provide a much better proxy of proteolysis than protease measurements which are "a poor index of muscle proteolysis" (Attaix. 2010), did after all indicate that there is no decrease in the rate of protein degradation when BCAA are consumed during a workout.
The real world significance of the often cited paper by Borgenvik, et al. in which the researchers from the Astrand Laboratory in Sweden describe a significant reduction of the said proteases in response to BCAA supplementation 3h after a workout is thus unlike Blomstrand's and Saltin's finding that "BCAA intake affects protein metabolism in muscle after but not during exercise in humans" (Blomstrand. 2001) questionable.
Why? Well, do you really consume intra-workout BCAAs but skip the muscle building protein shake after the workout? No... well, in that case you are already doing everything that's necessary to (a) maximize protein synthesis (see "There is a Ceiling Effect for Protein Synthesis W/ ~20-30g of Protein PWO" | read more) and reduce the catabolic proteases (Reitelseder. 2014).
learn more), will also lead to increases in tyrosine and phenylalanine levels and thus the accrual of skeletal muscle protein (Witard. 2014).
Unlike the anti-catabolic effects, the anti-DOMS effects of BCAAs are backed by science: Jackman et al. (2009) observed reductions in muscle soreness after eccentric exercise, Shimomura et al. (2010) observed a reduction in delayed-onset muscle soreness after a squat workout, Ra et al. (2013) report benefits of BCAAs in conjunction with taurine. However, none of the studies shows that (a) this effect would require intra-workout supplementation of BCAAs (the supplements were given before or after the workouts or as in the case of Matsumoto et al. (2009) before and during the workouts) and (b) none of the proves that the same effect wouldn't be observed with a simple BCAA rich whey protein.Against that background it is highly questionable, whether the often-heard decrease in protein breakdown and/or increase in anabolism during workouts in response to the ingestion of BCAAs during resistance training workouts even exists.
That is in contrast to endurance training, where Matsumoto, et al. (2007) report that the provision of a combined branched-chain amino acids and arginine supplement attenuates the efflux of phenylalanine from the muscle into the muscle. Similar results were observed, when Tang et al. (2006) analyzed the urinary nitrogen content of swimmers immediately post and 24 after 90 min medium intensity swimming. Unlike the study by Matsumoto et al., in which the BCAA + arginine supplement was administered 10 min after the first out of six exercise bouts, the study by Tang et al. did not use an intra-workout supplementation protocol, however.
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- Blomstrand, E., et al. "Administration of branched-chain amino acids during sustained exercise—effects on performance and on plasma concentration of some amino acids." European journal of applied physiology and occupational physiology 63.2 (1991): 83-88.
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