Moderate-intensity physical activity is independently associated with lower-extremity muscle power in older women

Skeletal muscle power is a salient determinant of physical function in older adults, but its relationship with habitual physical activity has not been well-characterized. The aim of this study was to examine the association between moderate-intensity physical activity and lower-extremity muscle power in community-dwelling older women. Older women (n = 96, mean age = 73.9 ± 5.6 years, mean body mass index = 26.5 ± 4.7 kg/m(2)) underwent assessments for body composition via dual-energy X-ray absorptiometry and lower-extremity muscle power (watts) using the Nottingham power rig. The Community Health Activities Model Program for Seniors questionnaire was used to estimate weekly caloric expenditure in moderate-intensity physical activity (kcals/wk). Linear regression indicated that moderate-intensity physical activity was independently related to muscle power (standardized β = 0.20, p = .03), and this relationship remained following adjustment for covariates. Analysis of covariance revealed that women in the highest tertile of volume of physical activity had significantly greater muscle power than those with the lowest volume (199.0 vs. 170.7 watts, p < .05). Moderate-intensity physical activity was independently associated with lower-extremity muscle power in older women. Future intervention trials should determine if increasing habitual physical activity is associated with improvements in lower-extremity muscle power in older women.