DETERMINANTS OF PEAK MUSCLE POWER - EFFECTS OF AGE AND PHYSICAL CONDITIONING

The relationships between absolute peak muscle power (W-peak), muscle cross sectional area (CSA(tot), i.e. the sum of both thigh and calf CSA) and muscle high energy phosphate concentration (adenosine 5'-triphosphate [ATP] and phosphocreatine concentrations [PC]) were studied in 47 subjects classified into five groups: A, 10 sedentary (S) subjects aged 20-35 years; B, 9 S aged 35-50 years; C, 9 S aged more than 50 years; D, 13 children aged 8-13 years; and E, 6 athletes (top level volleyball players) aged 24 (SD 3) years. The W-peak was measured during a maximal vertical high jump off both feet on a force platform. The CSA(tot) was measured anthropometrically. The [ATP] and [PC] were determined by (31)Phosphorus nuclear magnetic resonance spectroscopy. The W-peak decreased with age, was 65% lower in D than in A, and 43% higher in E than in A. The CSA(tot) did not vary with age, was 45% smaller in D than in A, and 15% greater in E than in A. The [ATP] and [PC] were essentially the same in all groups. The changes observed in W-peak were only partially accounted for by changes in CSA(tot). Therefore, in addition to the variables investigated, other factors appear to have been involved in the determination of W-peak peak With increasing age and training. An important role may be played by hormonal, particularly at puberty, and neural factors.