RESUMEN
The aim of this study was to verify the association of the ACTN3-R577X polymorphism with sarcopenia stage, according to the Revised European Consensus on the Definition and Diagnosis of Sarcopenia, in middle-aged and older adults, pre- and post- ST. In the 12-week longitudinal study, 71 middle-aged and older adults were evaluated; the participants were assigned to either control or intervention group. The intervention group underwent progressive ST three times a week. All participants underwent blood collection, DNA extraction, genotyping of the ACTN3-R577X polymorphism, anthropometric evaluations, and diagnostic tests for sarcopenia. The last two tests were repeated after 12 weeks. No association of the ACTN3-R577X polymorphism with sarcopenia stage was observed before and after 12 weeks. However, the intervention group remained non-sarcopenic (n = 25, p <0.05) or achieved changes in sarcopenia stage (from sarcopenic to non-sarcopenic) (n = 13, p <0.05). Our study demonstrates that progressive ST performed regularly can reverse or prevent sarcopenia regardless of genotype for the ACTN3-R577X polymorphism.