Effects of amino acid mixture of arginine, valine, and serine on anaerobic performance, muscle strength, and biochemical parameters after aerobic exercise in recreationally active men: a randomized, double-blind, placebo-controlled crossover study

Abstract

The aim of the present study was to examine the effect of an amino acid (AA) mixture of arginine, valine, and serine on exercise performance after prolonged exercise in humans. In a randomized, double-blinded, placebo-controlled crossover trial, nineteen recreationally active healthy males ingested an AA mixture of 1.8 g of arginine, 1.1 g of valine, and 0.1 g of serine or a placebo twice a day for 3 days and carried out a cycling exercise at 50% VO₂max for 90 min with a 15-min rest at the midpoint. After the exercise, subjects performed a 30-s Wingate test. Their leg and grip strength, rating scale of perceived exertion (RPE), and blood biochemical parameters were also evaluated. There were no significant differences between the two conditions in the Wingate test performance (peak power: AA 650.9 ± 80.8 vs placebo 644.7 ± 78.0, p = 0.585; mean power: AA 491.6 ± 58.8 vs placebo 490.8 ± 63.7, p = 0.907), leg and grip strength, or RPE score during exercise. The plasma noradrenaline concentrations in the AA condition were significantly higher than those in the placebo condition during exercise (p < 0.05). Moreover, strong correlations were found between the Wingate test performance and level of plasma noradrenaline (p < 0.001). These results indicated that the AA mixture supplement significantly elevated the plasma noradrenaline level during exercise, while sprint performance after prolonged exercise was not improved by the AA mixture supplement in the study.