The effects of HMB supplementation in highly-trained combat sport athletes (wrestlers, judokas, and Brazilian jiu-jitsu) was studied. The athletes maintained their usual daily training and dietary regimens during the placebo-controlled crossover study. HMB supplementation resulted in an increase in lean body mass and decrease in fat mass compared with placebo supplementation. In addition HMB supplementation resulted in increased aerobic capacity and anaerobic peak power. The authors concluded that for combat sport athletes, HMB promotes advantageous changes in body composition and aerobic and anaerobic capacity.