Effects of Branched-Chain Amino Acid Supplementation on Exercise Induced Muscle Damage and Delayed Onset of Muscle Soreness after a Bout of Eccentric Exercise

Branched-chain amino acids (BCAA) have the potential to reduce both exercise-induced muscle damage (EIMD) and delayed onset of muscle soreness (DOMS) after a bout of eccentric contractions (ECC). The purpose of this study was to determine the effects of BCAA supplementation for 12 days prior to and for an additional 7 days following a bout of ECC on EIMD and DOMS. Sixteen women with no prior experience with strength training were assigned randomly to a BCAA group or a placebo group. Only four participants completed the trial due to COVID-19 (another completed 72h of recovery and was included). Participants supplemented their diet with either 400mg•kg-1 of BCAA or fibre (placebo) for 19 days. On day 13 each participant performed 3 sets of 15 repetitions of ECC and EIMD parameters were measured throughout a week of follow-up. A definitive conclusion is not possible given the limited data. However, our data suggest that this BCAA supplementation protocol can mitigate some effects of EIMD such as perceived muscle soreness but would fail to provide a full recovery of maximal force output. More study involving BCAA supplementation and exercise damage is required to assess how BCAA affects EIMD and DOMS.