Abstract
Studies have demonstrated that motivation, aggression, excitation intensity, competitive spirit, and tolerance to psychological stress are included in major psychological factors affecting the performance of athletes. However, to date, there have not been sufficient scientific studies on the relationship between genetic polymorphisms affecting psychological abilities and competitive strength/sport. In this study, we compared the distribution of the brain-derived neurotrophic factor (BDNF) gene polymorphism (Val66Met) in athletes between competitive swimming, which needs closed skill without opponents, and judo, which needs open skill with opponents, in order to investigate the genetic basis of sports performance and related psychological factors. The results showed that the prevalence of Met carriers of the BDNF polymorphism associated with vulnerability to psychological stress was lower in judo players, suggesting that judo athletes had a higher stress tolerance. In addition, the prevalence of the BDNF heterozygous group was higher in competitive swimmers, supporting the hypothesis that closed skill sports without opponents receive less stress than open skill sports with opponents, furthre suggesting that they are excellent in motor control and motor learning.