Evaluation of muscle strength and its relation to exercise habits in Japanese.

The aim of this study was to explore muscle strength and its relation to exercise habits in Japanese. We used data from 3,018 men and 6,881 women aged 20-69 years and not using medications in a cross-sectional study. Exercise habits and muscle strength, i.e. grip strength and leg strength, were measured. Age-related changes in muscle strength were noted. Exercise habits were found in 984 men (32.6%) and 1,664 women (24.2%). For subjects of both sexes over 50 years, grip strength was significantly decreased with age. However, the ratio of leg strength to body weight significantly decreased with age as early as 30 years in men and 40 years in women. Grip strength, leg strength and the ratio of leg strength to body weight in subjects with exercise habits were significantly higher than those without exercise habits after adjusting for age in both sexes. This standard mean value may provide a useful database for evaluating muscle strength in Japanese adult subjects.