BCAA INGESTION DOES NOT IMPROVE CYCLING ENDURANCE
Foster, C., Faria, E., Chinevere, T., & Faria, I. (1998). Effect of branched-chain amino acid ingestion on moderate and high intensity cycling. Medicine and Science in Sports and Exercise, 30(5), Supplement abstract 92.
The hypothesis that branched-chain amino acid (BCAA) supplements reduce brain serotonin synthesis resulting in increased time to exhaustion, increased work output, and reduced perception of effort (RPE) was tested.
Endurance-trained cyclists (M = 16; F = 4) rode several times for 60 minutes at 70-75% VO2max after ingesting the following: A -- 25 gm of placebo; B -- 25 gm CHO gel plus BCAA (8.8 mg valine, 18 mg leucine, 6.3 mg isoleucine); and C -- 25 gm CHO gel plus BCAA (99 mg valine, 368 mg leucine, <20 mg isoleucine).
No significant differences in time to exhaustion, work output, or RPE were evidenced between conditions. However, when B and C conditions were combined 11 Ss demonstrated improved endurance capacity when compared to the placebo condition. No significant difference was found for post-exercise blood glucose or lactic acid levels.
Implication. BCAA ingestion does not improve performance of groups of cyclists. Some individuals demonstrate minor improvements in endurance performance after BCAA ingestion.
Return to Table of Contents for this issue.