The ACTN3 XX Genotype’s Underrepresentation in Japanese Elite Wrestlers

Abstract

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.

Born to fight? Genetics and combat sports

“…Concerning allele frequency (Figure 2), from the studies analysed the following results were observed when combat sports athletes and controls were compared: (1) ACTN3 -no difference for the three studies that investigated it (Kikuchi et al, 2012;Kikuchi et al, 2013;Rodríguez-Romo et al, 2013); (2) ACE -two studies reported difference between the athletes and the control groups (Cieszczyk et al, 2010;Kikuchi et al, 2012); (3) PPARα -one observed higher frequency (Cieszczyk et al, 2011), but the other did not (Ahmetov et al, 2006); (4) CKM -one found a higher frequency (Fedotovskaya et al, 2013).…”

“…To explain the differences in ACTN3 between wrestlers and controls, Kikuchi et al (2013) suggested that "individuals with the XX genotype, being completely deficient in α-actinin-3 protein, would have inferior function of skeletal muscles during the force generation of contraction or a low ability to recover from high-intensity intermittent exercise" (p.60). These factors might determine some aspects of performance in wrestling matches, which could help to explain why the ACTN3 RR allele and the RX genotype would be associated with the level of wrestlers' performance, especially in the international group analyzed by Kikuchi et al (2012).…”

“…However, Rodríguez-Romo et al (2013) did not find any difference for the ACTN3 R577X polymorphism between judo athletes and controls and attributed the absence of difference to the fact that judo is more likely a mixed-type sport than a pure power sport. Additionally, Kikuchi et al, (2013) suggested that XX individuals probably would need to have longer recovery time between heavy training sessions, and in case of fatigue, an individually set distribution of training sessions should be organized according to circumstances in order to avoid overtraining or muscle injury. genes in combat sport athletes and controls.…”

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“…The ACTN3 R allele and RR genotype are associated with the upper level of the power orientation in athletes in a wide range of ethnic groups [24,26]. In a meta-analysis Alfred, et al [27] it is shown that the ACTN3 RR genotype is more common among European athletes speed and power sports than among athletes.…”

“…These individuals are homozygous for the alleles coding a premature stop codon in the R577X (rs1815739, the transition C-to-T at nucleotide position 1729 in open reading frame ACTN3) [23,24]. Muscles pathology of these people is not observed, since α-actinin-2 compensates for its absence in muscle fibers which contraction is rapid.…”