The ACTN3 XX genotype's underrepresentation in Japanese elite wrestlers.

PURPOSE To examine the relationship between ACTN3 polymorphisms and level of athletic performance in Japanese wrestlers. METHODS The control group consisted of 243 healthy Japanese individuals. The authors divided 135 wrestlers into 3 groups based on their results in national or international competitions. They classified as elite 24 wrestlers who had placed in the top 8 in a world championship or participated in Olympic games, 28 wrestlers who had participated in world championships or become champions in Japan's national championships were classified as subelite, and 83 wrestlers were classified as national (N-W, ie, national-level wrestler). In addition, the authors combined the elite and subelite to form the classification international-level wrestlers (I-W). RESULTS The frequency of the null X allele and the XX genotype were significantly lower in the I-W group than in the control group. However, there was no significant difference in ACTN3 genotype or allele frequency between the N-W and control groups. The frequency of the ACTN3 XX genotype in the elite groups was lower than that of all groups, and a linear tendency was observed between ACTN3 XX genotype and athletic status. CONCLUSIONS In conclusion, the data indicated that ACTN3 polymorphisms were related to athletic performance in Japanese wrestlers.