Is there an association between ACTN3 R577X polymorphism and muscle power phenotypes in young, non-athletic adults?

We investigated the association between ACTN3 R577X polymorphism and jumping (vertical squat and counter-movement jump tests) and sprint ability (30 m dash) in non-athletic, healthy young adults [ N=284 (217 male), mean (SD) age: 21 (2) years]. We analyzed the differences in the study phenotypes among ACTN3 R577X genotypes by one-way analysis of covariance before and after adjusting for sex, age, weight and height (confounders). We also compared the genotype and allele frequencies between those with the best and worst results in the aforementioned tests (≥90th vs <90th of the sex-specific percentile, respectively). We used logistic regression to calculate the odds ratio (OR) for having the best performance. We did not observe a significant association between ACTN3 R577X genotypes and the study phenotypes before and after adjusting for potential confounders, nor after analyzing males and females separately. We did not observe significant differences in genotype frequencies between those with the best or the worst performance. The OR for an individual with the RR genotype to be in the top 10 percentile was <1.00 for jump tests and <1.015 for sprint tests (all P>0.05). In summary, α-actinin-3 deficiency does not negatively influence the ability to generate explosive leg muscle power in a young non-athletic population. [ABSTRACT FROM AUTHOR]