اثرات حاد مصرف دوز‌های مختلف مکمل بتاآلانین بر میزان خستگی عصبی- عضلانی و تجمع لاکتات متعاقب فعالیت ورزشی شدید اینتروال

Background & aims: 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. Material & methods: 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. Results: 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). Conclusion: 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.