Japanese Women’s Age-related Differences between Controlled Force Exertion Measured by a Computer-generated Sinusoidal Waveform and a Bar Chart Display

Abstract

Because developing an accurate method of measuring controlled force exertion is important, this study examined age differences in corresponding relationships between controlled force exertions measured by sinusoidal waveform and bar chart displays. Additionally, the study clarified the judgment score of the controlled force exertion’s decrease. Participants were 215 right-handed female adults, aged 20–84, in three age groups: young (n = 64, mean age 24, SD = 2.8 years), middle-aged (n = 91, mean age 43, SD = 8.0 years), and elderly (n = 60, mean age 68, SD = 6.5 years). They matched the submaximal grip strength in their dominant hand to changing demand values displayed on a personal computer screen as either a sinusoidal waveform or a bar chart. They performed the tests three times with 1-minute inter-trial intervals. The dependent variable was the total of percentage values of differences between the demand and grip exertion values for 25 seconds. In both displays, the coefficient of variance had almost the same range in all age groups (CVSW = 25.9–32.0, CVBC = 21.2–38.8), but the elderly group showed a somewhat higher value with the bar chart. Three groups had significant correlations between scores with the sinusoidal waveform and bar chart displays (r = 0.33–0.64), but their values did not differ significantly among age groups. Only 0%–3% of the middle-aged group had scores over 1500%; 23%–33% of the elderly group did. Furthermore, only 15% of the elderly group had scores over 1500% in both displays. There is a moderate relationship between the controlled force exerted in response to the sinusoidal waveform and bar chart displays, and it does not show age differences. In controlled force exertion, scores over 1500% in both displays are considered inferior to scores under 1500%.