Additive Benefits of β-Alanine Supplementation and Sprint-Interval Training

Abstract

Purpose: The present study investigated the effects of β-alanine supplementation only, and in combination with sprint-interval training (SIT), on training intensity, and energy provision and performance during exhaustive supramaximal-intensity cycling and a 4- and 10-km time trial (TT). Methods: Fourteen trained cyclists (VO2max = 4.5 ± 0.6 L·min-1) participated in this placebo-controlled, double-blind study. Subjects performed a supramaximal cycling test to exhaustion (equivalent to 120% VO2max) and a 4- and 10-km TT and 4 x 1-km sprints at three time points: before and after 28 d of supplementation loading (6.4 g·d-1) with β-alanine (n = 7) or a placebo (n = 7), and after a 5-wk supervised, SIT program performed twice weekly (repeated 1- km cycling sprints) whilst maintaining supplementation with β-alanine (1.2 g·d-1) or a placebo. Results: Following the loading period, sprint 3 and 4 of the 4 x 1-km sprint intervals were improved with β-alanine supplementation (4.5 ± 3.4% and 7.0 ± 4.0%; P < 0.05, respectively). After 5 wk of SIT, training intensity increased in both groups but the change was greater with β- alanine supplementation (9.9 ± 5.0% vs. 4.9 ± 5.0; P = 0.04). β-alanine supplementation also improved supramaximal cycling time to exhaustion to a greater extent than placebo (14.9 ± 9.2% vs. 9.0 ± 6.9%; P = 0.04), while 4- and 10-km TT performance improved to a similar magnitude in both groups. Following SIT, β-alanine also increased anaerobic capacity (5.5 ± 4.2%; P = 0.04), while VO2peak increased similarly in each group (3.1 ± 2.9% vs. 3.5 ± 2.9%; P < 0.05). Conclusion: These findings indicate that β-alanine supplementation enhances training intensity during SIT and provides additional benefits to exhaustive supramaximal cycling compared to SIT alone.