Résumé
The aim of the present study was to clarify the relationships between age-related changes of postural stability and physical function in middle-aged and elderly Japanese. The subjects were 640 males and 620 females who had participated in both the baseline and the 4-year follow-up surveys of the National Institute for Longevity Sciences-Longitudinal Study of Aging. Postural stability was measured using a force platform. Flexibility, muscle function, reaction time, balance and comfortable and maximal gait performance were also measured as physical function. Postural sway was increased in 4 years. Multiple logistic regression analysis controlled for age, sex, height, weight and history of diseases revealed significant relationships between decline of postural stability and sit-ups, flexibility, frequency and velocity at comfortable gait and leg extension power at baseline. These results suggest that not only greater abdominal muscle strength and leg power but also quick walking benefit the preservation of postural stability.