The effect of bcaa on isometric force following endurance exercise in a hot environment

Abstract

Introduction: Fatigue due to endurance exercise results from both peripheral and central changes, and may influence subsequent performance during a strength task. The increase in serotonin concentration is one of the central factors associated with endurance exercise-induced fatigue, particularly in hot environments. A nutritional strategy employed to reduce serotonergic activation is supplementation with branched-chain amino acids (BCAA). Objective: To investigate whether BCAA supplementation attenuates the reduction in isometric force caused by prior endurance exercise in a hot environment. Methods: Nine volunteers (aged 25.4 ± 1.2 years) performed a 2-min maximal voluntary isometric contraction (MVC ISO ) of upper limb muscles before and after an endurance exercise on a cycle ergometer at 40% of the maximal aerobic power. The volunteers underwent three experimental trials: 1) endurance exercise in a temperate environment (23°C and 60% RH); exercise in a hot environment (35°C and 60% RH) with the ingestion of: 2) a placebo solution or 3) a solution containing BCAA 30 mg.kg -1 . During the MVC ISO test, the isometric force of flexor muscles of the right elbow, core body temperature (TC ORE ) and heart rate (HR) were measured. Results: Isometric force decreased following endurance exercise in the hot environment, and BCAA administration did not attenuate this reduction. Greater T CORE and HR values were observed following endurance exercise in the heat, compared to pre-exercise values, and supplementation did not interfere with these physiological responses. Conclusion: The reduction in isometric force, caused by previous endurance exercise in a hot environment, was not diminished by supplementation with BCAA. Level of evidence I; Type of study: Therapeutic studies - Investigation of treatment outcomes.