Associations of accelerometry-measured and self-reported physical activity and sedentary behavior with skeletal muscle energetics: The Study of Muscle, Mobility and Aging (SOMMA)

•More time spent in accelerometry-measured (i.e., ActiGraph) and self-reported moderate-to-vigorous physical activity was associated with significantly higher skeletal muscle energetics (i.e., ATPmaxand maxOXPHOS).•More time spent in ActiGraph, but not self-reported daily sedentary behavior, was associated with lower skeletal muscle energetics.•Higher activPAL step count, but not time spent in sedentary behavior, was associated with higher ATPmaxand maxOXPHOS.•Older age was associated with lower muscle energetics for men but not women; adjustment for ActiGraph moderate-to-vigorous physical activity attenuated the age association with ATPmaxby 58%, indicating that higher intensity physical activity may offset age-related decline in ATPmax.