Determinants of maximal instantaneous muscle power in women aged 50-75 years

The present study aimed at analysing the age-related decline in maximal muscle power ((W) over dot) in 52 sedentary healthy women aged between 50 and 75 years to determine whether force or velocity is the major determinant. Maximal muscle power was estimated from two types of vertical jumps, squatting (SJ) and countermovement (CmJ), performed on a force platform. It was obtained by measuring the vertical force (F-opt) applied to the body centre of gravity and calculating the corresponding vertical velocity (v(opt)). An age-related decline in absolute (W) over dot was statistically significant in all the conditions examined and in both peak (W) over dot and average power W-radical anion values. The decrease in v(opt) was also statistically significant. Also F-opt declined but this reduction was not statistically significant with the exception of the average value in CmJ. Not surprisingly the highest (W) over dot were obtained in CmJ, and the difference in power production between the two types of jump showed an age-related decrement only in W-radical anion. The main finding of the study was the demonstration that v(opt) was the critical determinant of the age-related decline in (W) over dot in healthy elderly women.