Age-Related Corresponding Relationships of Controlled Force Exertion Measured by a Computer-Generated Sinusoidal and Quasi-Random Display

Abstract

This study examined age-group corresponding relationships of the controlled force exertion based on sinusoidal and quasi-random waveforms in 175 right-handed male adults aged 20 to 86 years. The subjects were divided into 3 groups based on age-level: 53 young (mean age 24.6, SD = 3.3 years), 71 middle aged (mean age 44.3, SD = 8.7 years), and 51 elderly (mean age 69.3, SD = 6.4 years). The participants matched their submaximal grip strength by the dominant hand to changing demand values displayed as either a sinusoidal or a quasi-random waveform appearing on the display of a personal computer. The quasi-random waveform was changed in π with amplitude and in π/2 with frequency (peak and mean frequency were 0.1 Hz in both waveforms). The participants performed the controlled force exertion test three times with a 1-min interval (one trial was 40 sec) after one practice trial using the dominant hand. The measurement order was randomly assigned. The total of the differences between the demand value and grip exertion value for 25 sec were used as an evaluation parameter. The coefficient of variance was almost the same range in all age groups in both waveforms (CVSW = 30.8–35.6, CVRW = 26.3–37.7), but the elderly group showed the highest value in the quasi-random waveform. Significant correlations were found among the sinusoidal and quasi-random waveforms in the young, middle-aged, and elderly groups, but significant differences were not found in the correlations among each age group. The controlled force exertion evaluation based on the sinusoidal and quasi-random waveform displays has a moderate relationship, and this relationship does not show age-level differences.