Effects of branched-chain amino acids supplementation on physiological and psychological performance during an offshore sailing race

The aim of the present study was to investigate the effect of protein diets, rich in branched chain amino acids (BCAA) on perceived exertion, mental and physical performance during an offshore sailing race that lasted 32 h. Twelve sailors were randomly allocated into one of two groups [Control (CON) and BCAA: n = 6/group]. The BCAA group consumed a standard diet of 11.2 MJ day −1 (58% carbohydrate, 30% fat, 12% Protein) along with a high-protein supplement of 1.7 MJ day −1 (40% carbohydrate, 35% protein, 25% fat) and 1.7 MJ day −1 composed of 50% valine, 35% leucine, and 15% isoleucine. CON was given a standard diet of 14.5 MJ day −1 (58% carbohydrate, 30% fat and 12% protein). During the race, heart rate was monitored. Subjects self-evaluated their feeling of fatigue every 3 h, and 12 samples of saliva from each subject were collected to perform cortisol assays. Before and after the race a vertical jump and a handgrip test were performed, and mental performance was evaluated with a standardized battery of tests. A significant increase in the feeling of fatigue was noted on the second day (D2) of race in both groups; the increase was higher in CON ( P