BRANCHED-CHAIN AMINO ACID PLUS CARBOHYDRATE SUPPLEMENTATION HAS THE SAME EFFECT ON ENDURANCE CYCLING AS CARBOHYDRATE ALONE
Skillen, R., Casazza, G. A., Testa, M., Applegate, E., & Heiden, E. A. (2006). Branched chain amino acid supplementation and exercise performance. Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 1986.
This study determined whether consumption of an iso-caloric carbohydrate and branched-chain amino acid (BCAA) beverage versus a carbohydrate-only (CHO) beverage affects endurance cycling performance, fuel use, and blood glucose and lactate concentrations. Competitive male cyclists and triathletes (N = 8) cycled at 75% VO2max for 90 minutes followed by a ride to exhaustion at 85% VO2max. Exercise started 2-3 hours after a standardized breakfast, diet was controlled for the 12 hours before exercise, and Ss were well rested to ensure adequate glycogen stores. Ss consumed 7 ml/kgBW of double-blinded and randomly assigned, CHO (3.6%) plus BCAA (0.8%) or CHO only (4.6%) beverage before and after exercise and 1.8 ml/kgBW every 15 minutes during exercise. Oxygen consumption(VO2), respiratory exchange ratio, rate of perceived exertion, heart rate, blood glucose, lactate, and hematocrit concentrations were collected 15 minutes before, every 15 minutes during, and immediately following exercise. Time to exhaustion was measured as the time cycled before dropping below 60 rpm.
Body weight, % body fat, and VO2max did not change significantly between the two beverage protocols. Time to exhaustion did not differ significantly between the two treatments. There also were no significant differences between the groups for VO2, respiratory exchange ratio, rate of perceived exertion, heart rate, blood glucose, lactate, and hematocrit concentrations at rest or during exercise.
Implication. Endurance time to exhaustion was similar between carbohydrate plus branched-chain amino acid and carbohydrate alone following pre-, during-, and post-exercise ingestion.
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