Comparison of explosive force between young and elderly women: evidence of an earlier decline from explosive force.

The aging process causes many changes in muscle strength, and analysis of explosive force from handgrip strength seems to be useful and promising in studying the aging musculoskeletal system. Therefore, the purpose of this study was to investigate if explosive force parameters [rate of force development (RFD) and contractile impulse (CI) over the time interval of 0-200 ms from the onset of contraction] during handgrip efforts decline differently than maximum handgrip strength with increasing age. Twenty healthy young women (20-27 years) and 65 healthy elderly women, assigned into three age groups (50-64, 65-74, and 75-86 years), participated in this study. All participants performed two maximal grip attempts. Handgrip data were recorded as force-time curves, peak force, and explosive force parameters. Our results revealed that peak force decreased significantly (p < 0.05) for those who are 65 years old, while explosive force parameters decreased significantly (p < 0.05) for those aged 50 years. These data indicate that the decline in explosive grip force-generating capacity may begin earlier (i.e., for those aged 50 years old) than peak force during the aging process. Our findings suggest that the aging process reduces the explosive grip force-generating capacity before affecting peak force.