Branched-chain amino acids (BCAA) are essential amino acids that have to be ingested in your diet since they can’t be synthesized in your body. BCAAs are abundant in muscle proteins. Unlike other essential amino acids which are broken down in the liver, BCAA catabolism occurs primarily in muscle. The breakdown of BCAA in muscle tissue is promoted by exercise.
Researchers in Japan published the results of a study on supplementation with branched-chain amino acids (BCAA) on squat-exercise induced delayed-onset muscle soreness (DOMS) in International Journal of Sport Nutrition and Exercise Metabolism (Shimorura et al, 2010). For this particular study, it involved 12 female untrained participants.
Branched-Chain Amino Acids:
The participants ingested branched-chain amino acids containing isoleucine, leucine, and valine, at the following ratios: isoleucine:leucine:valine = 1:2.3:1.2. The BCAA were consumed in a green-tea drink which contained a total of 5.5 g of BCAA. A placebo drink containing the same ingredients was also used with dextrin being substituted for the BCAA.
The exercise included 7 sets of 20 squats /set with 3 minutes of rest in between.
- Delayed-onset muscle soreness (DOMS) peaked on days 2 and 3
- Delayed-onset muscle soreness was significantly lower in the branched-chain amino acid group
- Plasma branched-chain amino acids were markedly elevated 2 hrs after exercise in the BCAA group and significantly lower after exercise in the placebo group.
- Serum myoglobin (a marker of muscle damage) was increased by exercise in the placebo group but not the branched-chain amino acid group.
- On day 3, maximal voluntary isometric contractions were reduced to 80% in the control group, but remained unchanged in the BCAA group.
Bottom line: Pre-exercise branched-chain amino acid supplementation appears to be useful to prevent delayed-onset muscle soreness and muscle damage in untrained female athletes. A previous study showed similar results in untrained men.
- Shimomura Y, Inaguma A, Watanabe S, Yamamoto Y, Muramatsu Y, Bajotto G, Sato J, Shimomura N, Kobayashi H, Mawatari K. Branched-chain amino acid supplementation before squat exercise and delayed-onset muscle soreness. Int J Sport Nutr Exerc Metab. 2010 Jun;20(3):236-44.