β-alanine improves punch force and frequency in amateur boxers during a simulated contest

摘要

The aim of this study was to test the hypothesis that β-alanine supplementation improves punch power and frequency in amateur boxers during a simulated contest. Sixteen amateur boxers (each approximately 6 years experience) were assigned to β-alanine (n=8; 1.5 g x 4 times/d for 4 wks) or placebo supplementation (n=8), after initially being assessed for baseline punch performance. Before and after the supplementation period, all boxers completed a simulated contest consisting of 3 x 3 minute rounds (interspersed with 60 s rest) on a punch bag (with a force transducer attached). Each round involved 2 minutes 50 seconds performing standardised punching (standardised jab, cross combination) based on notation analysis, whereas the last 10 seconds involved maximal output punching (standardised jab, cross combination) during which time, punch force and frequency were recorded. Postcontest blood lactate was significantly increased in the β-alanine group (Pre-supplementation: 9.5 ± 0.9 mmol.L-1, Post-supplementation: 12.6 ± 0.5 mmol.L-1, P<0.05) whereas the placebo group showed no change (Pre-supplementation: 8 ± 2.8 mmol.L-1, Post-supplementation: 7.0 ± 2.7 mmol.L-1, P>0.05). During the 10 seconds maximal output punching, changes in mean punch force (β-alanine: 20 ± 1.01 kg: placebo 1 ± 1 kg) and punch frequency (β-alanine: 5 ± 4: placebo -2 ± 3) was greater (P<0.05) in the β-alanine supplemented group. We conclude that β-alanine supplementation improves punching performance in amateur boxers and suggest that this supplementation protocol may also prove ergogenic for other related combat sports.