Purpose: Recent research has shown that chronic dietary β-alanine (βALA) supplementation increases muscle carnosine content, which is associated with better performance in short (1-2 min) maximal exercise. Success in endurance competitions often depends on a final sprint. However, whether βALA can be ergogenic in sprint performance at the end of an endurance competition is at present unknown. Therefore, we investigated the effect of 8-wk βALA administration in moderately to well-trained cyclists on sprint performance at the end of a simulated endurance cycling race.
Methods: A double-blind study was performed, which consisted of two experimental test sessions interspersed by an 8-wk βALA (2-4 g·d−1; n = 9) or matched placebo (PL; n = 8) supplementation period. In the pretesting and the posttesting, subjects performed a 10-min time trial and a 30-s isokinetic sprint (100 rpm) after a 110-min simulated cycling race. Capillary blood samples were collected for determination of blood lactate concentration and pH.
Results: Mean power output during the time trial was approximately 300 W and was similar between PL and βALA during either the pretesting or the posttesting. However, compared with PL, during the final sprint after the time trial, βALA on average increased peak power output by 11.4% (95% confidence interval = +7.8 to +14.9%, P = 0.0001), whereas mean power output increased by 5.0% (95% confidence interval = +2.0 to +8.1%, P = 0.005). Blood lactate and pH values were similar between groups at any time.
Conclusion: Oral βALA supplementation can significantly enhance sprint performance at the end of an exhaustive endurance exercise bout.
Department of Biomedical Kinesiology, Research Centre for Exercise and Health, Katholieke Universiteit Leuven, Leuven, BELGIUM
Address for correspondence: Peter Hespel, Ph.D., Research Centre for Exercise and Health, FaBeR-Katholieke Universiteit Leuven, Tervuursevest 101, B-3001 Leuven, Belgium; E-mail: firstname.lastname@example.org.
Submitted for publication April 2008.
Accepted for publication September 2008.