Association between R577x and the physical performance of Chinese 13 to 15-year-old elite and sub-elite football players at different positions.

The purpose of this study was to investigate the prevalence of polymorphisms in Chinese elite and sub-elite football players aged 13-15 years at different positions. Specifically we explored whether genotypes were linked with athletic performance of elite and sub-elite players at different positions. The RR genotype frequency of elite defenders ( = 0.018) and midfielders ( = 0.008) was significantly higher than that of sub-elite XX genotype in elite players. Furthermore, the R allele frequency of elite defenders ( = 0.003) and midfielders ( = 0.008) was significantly higher than that of sub-elite players. In all subjects, RR players performed faster and exhibited more explosive power than RX or XX players. RR, RX and XX elite players' 20 m/30 m sprint, 5 × 25-m repeated sprint ability (5 × 25 m RSA), and standing long jump were stronger than sub-elite players, but there was no significant different in aerobic endurance between elite and sub-elite players at different positions. In conclusion, there were significant differences in genotypes and alleles between elite and sub-elite players at different positions, and the RR genotype was significantly associated with power-related athletic performance in Chinese youth football players.