Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article


Master of Science




Lemon, Peter


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.

Summary for Lay Audience

Amino acids (AA) are the building blocks of body protein. The branched-chain amino acids (BCAA) are a group of three essential (cannot be made by the body) amino acids (leucine, isoleucine and valine) which are often recommended to boost muscle protein synthesis (MPS), especially leucine and/or enhance exercise performance. Further, some data suggest that BCAA supplementation can reduce exercise-induced muscle damage (EIMD) and muscle soreness after exercise. However, there is no consensus regarding the optimal amount of BCAA that an individual should consume to reduce EIMD and soreness. Therefore, the purpose of this experiment was to examine if 400mg•kg body mass-1 daily BCAA supplementation starting 12days prior to ECC exercise and throughout a week after exercise could mitigate muscle damage and soreness. The muscle damaging exercise involved 3 sets of 15 repetitions of ECC elbow muscle extension. 16 women with no strength training experience were assigned randomly into two groups (BCAA vs fibre). Only 4 completed all data collection due to COVID-19. Our data suggest that BCAA supplementation can reduce both EIMD and muscle soreness. More research is needed to establish the optimal dose for BCAA consumption for different types of exercise.