INFLUENCE OF LEUCINE SUPPLEMENTATION ON SERUM AMINO ACID CONCENTRATION AND ANAEROBIC RUNNING PERFORMANCE 1095

Abstract

The purpose of this study was to examine the influence of leucine supplementation on the serum amino acid (n=21) concentrations and anaerobic running performance in active male sprinters (n=12; 26±5 years). The subjects underwent at 7 days interval two maximal anaerobic running tests on a treadmill (MART; n × 20 s with a recovery of 100 s between the runs) until exhaustion. The randomized subjects consumed drinks containing leucine(L)(200 mg × kg-1 body weight) or placebo (P) 50 min before the test runs. Blood samples 10 min before (B) and after (A) the test runs were analyzed for serum amino acids using an automatic Pharmacia LKB Alpha Plus amino acid analyzer. The leucine administration significantly (p=0.003) increased the total concentration of branched-chain amino acids in both B and A samples. The concentration of leucine was higher in L than P group in both B(p=0.007) and A (p= 0.003) samples. The concentrations of isoleucine and valine in B samples were similar in both groups but decreased in A samples in L group (p=0.020 for isoleucine and p=0.006 for valine). In the MART, the running velocity and peak concentration of blood lactate were the same in L and P groups (7.66 ± 0.28 m × s-1, 20.7 ± 2.2 mmol× 1-1 and 7.63 ± 0.29 m × s-1, 20.7 ± 2.4 mmol × l-1, in L and P groups respectively). These findings indicate that leucine supplementation diminishes the serum isoleucine and valine concentrations during anaerobic running but has no effect on performance.