Acute effects of different doses of beta-alanine supplement on neuromuscular fatigue and lactate accumulation after intense interval exercise

Some studies have shown that beta-alanine supplementation may delay fatigue during strenuous exercises. The aim of this study was the effect of 10 days β-alanine supplementation with different doses on neuromuscular fatigue and blood lactate levels. 40 active men with a mean age of 21.9±2.6 years and body mass index 24.54±1.8 kg/m2 were randomly divided into four groups of 10 people including: 2, 4 and 6 g doses of beta-alanine supplement (Experimental groups) and placebo (control) group. Competitors completed four 30-second Wingate tests with maximum power, before and after 10 days beta-alanine supplementation period. 4 minute rest interval was set between each exercise. The first blood sampling administrated before first exercise and second one after 6 minutes of fourth exercise. The EMG amplitude as neuromuscular fatigue index was measured before the first wingate and during the fourth wingate test. the result showed that supplementation with different doses of β-alanine has no effect on M wave amplitude in vastus lateralis muscle. In other words, neither within-group (P=0.078) and between-group changes (P=0.66) was significant. Moreover, after repeated wingate exercises, amount of lactate in all groups (received β-alanine supplement and placebo group) increased significantly (p=0.000), while, no difference showed between groups (p=0.1). The present findings suggest that doing repetitive maximal exercises results in significant increase of lactate, but short-term β-alanine supplementation with different doses has no effect on neuromuscular fatigue and blood lactate accumulation.