Effect of Branched-chain Amino Acid Supplementation on Muscle Damage

Effect of Branched-chain Amino Acid Supplementation on Muscle Damage in Recreational Athletes

Seventy-eight recreational athletes who never resistance trained will be randomly assigned into three groups of twenty-six. Branched-chain amino acid will be supplemented for 18days at 0, 200 or 400 mg/body weight(kg)/day in jelly. Participants will be asked to perform elbow flexions on the 12th day of supplementation. Maximum voluntary contractions will be measured before, during and after the supplementation period to compare the effects of different doses of branched-chain amino acid has on muscle damage markers.

Previous studies have not been able to show consistent effects due to various reasons. The major limitations are the lack of enough data on the amount and duration of branched-chain amino acid supplementation, and the level of muscle damage for branched-chain amino acid to be effective. Based on a recent meta-analysis, it has been suggested that to be effective, branched-chain amino acid should be supplemented more than 200mg/kg/day before a low-to-moderate intensity exercise bout. Therefore, this study is designed based on the above suggestions and to compare the effect of different doses of branched-chain amino acid on muscle damage markers in healthy recreational active individuals.

Three treatment groups (n=26) will be randomly assigned to be supplemented with either 200mg BCAA/kg/day (BCAA200), 400mg BCAA/kg/day (BCAA400) or placebo (fiber supplement; PL). Supplements will be provided in jelly in a single blind fashion to be ingested 1hour after each of the three main daily meals for 18days. Anthropometric measurements (body weight, lean mass, height), body temperature, ultrasound (US), strength assessment (maximal voluntary contraction, MVC), resting metabolic rate (RMR), rate of perceived exertion (RPE), delayed onset of muscle soreness (DOMS) and blood samples (duplicates; myoglobin; BCAA) will be collected before, during and after the supplementation period at different time points (see appendix for the above tables). Repeated-bout effect (RBE) on both arms will be measured 7 days after the damage inducing session.

Inclusion Criteria:

• Healthy males and females at the age of 18-40
• Endurance trained athletes
• Weekly exercise duration is less than 150minutes but more than 30 minutes

Exclusion Criteria:

• Individuals who cannot endure three days for not eating meat
• Diabetic
• Have been performing resistance trainings
• Have been taking protein supplement
• Have been consuming a high level of protein in the regular diet
• Have been taking omega-three and vitamin E supplements
• Have been taking anabolic Steroids
• Have been taking regular medications
• Have cardiovascular Disease
• Have a history of joint & Muscle Injuries
• Females with irregular Menstrual Cycle