Abstract
In this study, we invented a simple method to measure the ankle plantar flexor muscle strength using a handheld dynamometer, and examined the reproducibility and validity of the measured values. The subjects were 17 healthy adults and their 34 legs. We measured the strength of their ankle plantar flexor muscle, knee extensor muscle, and grip. To examine the reproducibility of the measurements of the ankle plantar flexor muscle strength, we applied its interclass correlation coefficients using the test-retest method. To examine its validity, we compared its Pearson correlation coefficientswiththoseofthe knee extensor muscle and grip. As a result, we observed that the reproducibility of our new method to measure the ankle plantar flexor muscle strength was favorable. We also observed significant correlations between its measured value and that of the knee extensor muscle strength, which we used to assess the lower-limb muscle strength, as well as that of the grip strength, which we used to assess the upper-limb muscle strength. The results suggest that our new method to measure the ankle plantar flexor muscle strength is highly reproducible, and a simple and effective way to measure the muscle strength reflecting that of the knee extensor muscle and grip.