Branched-chain amino acids (BCAA) are major building blocks of proteins and are known to promote protein synthesis. In the present study, we addressed to examine the effects of BCAA on muscle damage induced by exercise in humans and rats. Since it has been reported that delayed-onset muscle soreness (DOMS) induced by squat exercise is decreased by supplementation of 5 g BCAA before exercise, we examined effects of the BCAA supplementation (0.1 g/kg BW) just after exercise. The results obtained showed that the BCAA supplementation just after exercise tended to decrease DOMS, but was not so effective as the supplementation before exercise. These findings let us to conclude that the BCAA supplement should be ingested before exercise to obtain the BCAA efficacy. In the animal study, we used rats catheterized through jugular vein in order to take blood samples at many time points. The skeletal muscles of the rat hindlimb were contracted by electric stimulation and muscle damage was detected by measurement of serum creatine kinase activity. Further study is required to establish the rat model for exercise-induced muscle damage.

DESCENTE SPORTS SCIENCE Vol.28/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE