The effect of beta-alanine supplementation on power performance during repeated sprint activity

The dipeptide carnosine has been shown to contribute to the buffer capacity of hydrogen ions (H) during intense exercise. Increasing skeletal muscle carnosine levels through beta-alanine (BA) supplementation has been shown to maintain acid-base balance, delay fatigue, and improve exercise performance. We designed this study to examine the effect of 5 weeks of BA supplementation on repeat high-intensity sprint performance. Nineteen, physically active, college men were divided into 2 groups (control [C], n = 10 or BA, n = 9). We performed double-blind placebo-controlled study where subjects ingested 4 g per day during the first week and 6 g per day over the next 4 weeks of a placebo (rice flour) or a BA supplement. Subjects completed 2 sets of 5 5-second sprints with 45-second recovery separated by 2 minutes of active recovery. All tests were conducted on a non-motorized treadmill against a resistance of 15% of the participant's body weight. We recorded horizontal power (HP) of the running sprint. Post-exercise capillary blood samples were analyzed for lactate to determine the metabolic demands. There were no significant between-group differences (p > 0.05) in HPpeak or HPmean for the repeat sprint protocol. No significant between-group differences were found for performance decrement (% fatigue) for HPpeak or HPmean. In addition, no significant interactions were observed. Post-exercise blood lactate values were similar pre and post supplementation in both groups. The results of this study clearly indicate that 5 weeks of BA supplementation provides no benefit for repeat sprint performance.