Background: The ACTN3 R577X polymorphism has been shown to influence athletic performance. The aim of the present study was to examine the association between ACTN3 R577X
polymorphism(rs1815739), athletic competition level, and lower-extremity power in elite Chinese sprint/power and endurance athletes.
Methods: We compared the genotype and allele frequencies of the ACTN3 R577X polymorphisms between59 elite sprint/power (S/P) athletes, 44 elite endurance (E) athletes, and 50 healthy
controls (C) from Chinese Han origin. We also compared the lower-extremity power in the athletic cohort.
Results: The genotype distribution of the S/P athletes was significantly different from the elite E athletes (P=0.001) and C group(P<0.001). The frequency of the RR genotype in
international-level S/P athletes was significantly higher than that of the national-level athletes (who only compete nationally) (P=0.004), with no XX genotype in the international-level S/Pcohort.
The RR S/P athlete’s personal best achievement, in both the standing long jump and vertical jump, was better than their RX+XX counterparts (P<0.05 and P<0.01, respectively).
Conclusions: ACTN3 R577X polymorphism is associated with sprint/power athletic status, and lower extremity power, in elite Chinese athletes. Including relevant phenotypes like muscle
performance in future studies is important to further understand the relative role of gene variants in athletic performance outcomes.