Effect of Beta-Alanine Supplementation on Sprint Endurance

Abstract

EFFECTS OF BETA-ALANINE SUPPLEMENTATION ON SPRINT ENDURANCE. PURPOSE: Recent research has shown that beta-alanine supplementation can increase intramuscular carnosine levels. Carnosine is an intramuscular buffer and has been linked to improvements in performance, specifically during bouts of high intensity exercise that are likely limited by muscle acidosis. Therefore the purpose of this study was to examine the effect of beta-alanine supplementation (BA) on sprint endurance at two different supramaximal intensities. METHODS: Twenty-one anerobically trained [rugby players (n = 4), wrestlers (n = 11) and recreationally strength-trained athletes (n = 6)] college men participated in a double blind, placebo controlled study. Subjects performed an incremental V̇o2 max test and two sprint to exhaustion tests set at 115% and 140% of their V̇o2 max on a motorized treadmill before (PRE) and after (POST) a 5 week supplementation period. During this time subjects ingested either a BA supplement or placebo (PLA) with meals. Subjects ingested 4g /day of BA or PLA during the first week and 6g/day the following 4 weeks. Capillary blood samples were taken before and after each sprint to determine blood lactate response to the sprint exercise RESULTS: No significant group (BA, PLA) × intensity (115%, 140%; p = 0.60), group by time (PRE, POST; p = 0.72), or group × intensity × time (p = 0.74) interactions were observed for time to exhaustion (See Table 1). In addition, similar non-significant observations were made for lactate response to the sprints (group × intensity, p = 0.43; group × time, p = 0.33, group × intensity × time, p = 0.56) Conclusion: From the results of the current study, it was concluded that beta-alanine supplementation did not have a significant effect on sprint endurance at supramaximal intensities. Beta-alanine has been shown to increase carnosine levels within the muscle and thought to improve the buffering capacity of human muscle during high intensity exercise. However, anaerobic training has been shown to increase carnosine levels. In addition, there may be a ceiling effect as to how much carnosine can be stored within the muscle. This effect may have accounted for our inability to show that BA improves performance in sprint exercise lasting between 1-3 in duration. Practical Applications: Based on the results of this study, anaerobically trained athletes that participate in sports requiring extended bouts of high intensity exercise (i.e. long duration sprinters, rowers, speed skating etc.) may not benefit from beta-alanine supplementation. This is likely due to a ceiling effect caused by high initial levels of carnosine because of their training status.