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Effects of Oral Branched‐Chain Amino Acids BCAAs

Effects of Oral Branched‐Chain Amino Acids (BCAAs) Intake on Muscular and Central Fatigue During an Incremental Exercise
Effects of Oral Branched‐Chain Amino Acids (BCAAs) Intake on Muscular and Central Fatigue During an Incremental Exercise


The aim of this study was to investigate the effects of oral branched-chain amino acids (BCAAs) intake on muscular (creatine kinase and myoglobin) and central (serotonin) fatigue during an incremental exercise protocol and to determine the time to exhaustion.

BCAAs (leucine, isoleucine and valine), which form one-third of total muscle protein, are the only amino acids metabolised in skeletal muscle. Oral BCAAs ingestion is commonly used by athletes as a nutritional supplement to reduce central fatigue by lowering 5-HT activity and increasing dopamine synthesis and release, to trigger neural signals, and to enhance physical performance. Several studies have indicated that taking BCAAs before and during prolonged exercise can alleviate central fatigue and muscular fatigue.



Sixteen male long-distance runners who were members of the Jordan Military Sports Federation participated in this study.

Experimental design

This study was a randomised, double-blind trial with a crossover design. The protocol consisted of two trials: a BCAA (supplement) trial and a placebo trial, 14 days apart. Both trials started in the early morning (8:30 AM) to avoid effects of a circadian rhythm, as it is well established that athletic performance is influenced by the circadian rhythm.


The purpose of this study was to investigate the effect of oral intake of BCAAs on biomarkers of muscular and central fatigue and to determine time to exhaustion, in long-distance runners, during an incremental treadmill exercise test. We hypothesised that the intake of BCAAs supplement would alter serotonin concentration during exercise and that this would enhance performance.


Em conclusão, a ingestão oral de BCAAs teve um efeito positivo no desempenho dos corredores de longa distância em um teste incremental em esteira. Isso sugere que a ingestão de 20 g de BCAAs dissolvidos em 400 ml de água com 200 ml de suco de morango 1 hora antes de uma sessão incremental de exercícios aumenta o tempo até a exaustão, provavelmente devido à redução na concentração plasmática de serotonina, que atrasa o início da fadiga central . Nossos resultados mostraram que o tempo de exaustão foi aumentado pela ingestão oral de BCAAs, que têm um papel importante no gasto de energia durante o exercício, além de atenuar o aumento induzido pelo exercício na relação TRP: BCAAs e, assim, evitar altos níveis plasmáticos de serotonina.

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J Hum Kinet. 2020 Mar; 72: 69–78.Published online 2020 Mar 31. doi: 10.2478/hukin-2019-0099

Bcaa Branched Chain Amino Acid With Scoop And Dumb

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