This study investigated the effect of a supplement containing 9 essential and 3 non-essential amino acids on muscle soreness and damage by comparing two endurance exercise bouts of the elbow fexors with amino acid or placebo supplementation in a double blind crossover design. The supplement was ingested 30 min before (10 h post-fasting) and immediately after exercise (Experiment 1), or 30 min before (2-3 h after breakfast), immediately post, and 8 more occasions over 4-day post-exercise (Experiment 2). Changes in muscle soreness and indicators of muscle damage for 4 days following exercise were compared between supplement conditions using two-way ANOVA. No significant differences between conditions were evident for Experiment 1; however, plasma creatine kinase, aldolase, myoglobin, and muscle soreness were significantly lower for the amino acid versus placebo condition in Experiment 2. These results suggest that amino acid supplementation attenuates DOMS and muscle damage when ingested in recovery days.
Kazunori Nosaka and P. ▀ Sacco are with the School of Exercise, Biomedical and Health Sciences, Edith Cowan University in Joondalup, Australia. E-mail: email@example.com. P ▀ Sacco is also with the School of Health and Bioscience at the University of East London, UK. K.▀ Mawatari is with Amino-Science Laboratories, Ajinomoto Co. Inc. in Tokyo, Japan