Quadriceps muscle function in relation to habitual physical activity and (V)over-dot O2max in men and women aged more than 65 years

The relationship of quadriceps maximal muscle power (P-max), corresponding optimal shortening velocity (v(opt)), and relative fatigability (Pmax%D) to maximal oxygen uptake ((V) over dot O(2)max) and habitual physical activity (PA) was examined in healthy community-dwelling subjects (29 women and 25 men) aged more than 65 years old. PA was evaluated by a questionnaire and expressed using two activity indices: mean habitual daily energy expenditure MHDEE) and the daily energy expenditure corresponding to leisure time sports activities (Sports Activity). In women, P-max correlated positively with (V) over dot O(2)max (r = .56) and with Sports Activity (rho = .41). Both Sports Activity and P-max were significant independent predictors of (V) over dot O(2)max and accounted for 62% of variance in (V) over dot O(2)max. In men, v(opt) was significantly negatively related to MHDEE (r = -.59) and to Sports Activity (rho = -.40). Neither in women nor in men was Pmax%D correlated with (V) over dot O(2)max or PA indices. The different relationship of P-max and v(opt) with (V) over dot O(2)max and PA indices suggests that habitual PA may be sufficient in active older women, but not in men, to positively influence quadriceps muscle function. These gender differences may suggest different approaches in exercise programming for elderly women and men.