Alpha-actinin-3 (ACTN3) R577X polymorphism influences knee extensor peak power response to strength training in older men and women

J Gerontol A Biol Sci Med Sci. 2007 Feb;62(2):206-12. doi: 10.1093/gerona/62.2.206.


Background: The alpha-actinin-3 (ACTN3) R577X polymorphism has been associated with muscle power performance in cross-sectional studies.

Methods: We examined baseline knee extensor concentric peak power (PP) and PP change with approximately 10 weeks of unilateral knee extensor strength training (ST) using air-powered resistance machines in 71 older men (65 [standard deviation = 8] years) and 86 older women (64 [standard deviation = 9] years).

Results: At baseline in women, the XX genotype group had an absolute (same resistance) PP that was higher than the RR (p =.005) and RX genotype groups (p =.02). The women XX group also had a relative (70% of one-repetition maximum [1-RM]) PP that was higher than that in the RR (p =.002) and RX groups (p =.008). No differences in baseline absolute or relative PP were observed between ACTN3 genotype groups in men. In men, absolute PP change with ST in the RR (n = 16) group approached a significantly higher value than in the XX group (n = 9; p =.07). In women, relative PP change with ST in the RR group (n = 16) was higher than in the XX group (n = 17; p =.02).

Conclusions: The results indicate that the ACTN3 R577X polymorphism influences the response of quadriceps muscle power to ST in older adults.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Actinin / genetics*
  • Aged
  • Aged, 80 and over
  • Arginine
  • Cross-Sectional Studies
  • Exercise*
  • Female
  • Humans
  • Knee*
  • Male
  • Middle Aged
  • Muscle Contraction / genetics*
  • Muscle Strength / genetics*
  • Physical Endurance
  • Physical Exertion
  • Physical Fitness
  • Polymorphism, Genetic*
  • Sex Characteristics


  • ACTN3 protein, human
  • Actinin
  • Arginine