The purpose of this study is to identify the effects on physical ability among the people who are doing physical activities constantly. This study was done by a 8-year-follow-upresearch which examined 8 middle- aged people, who had done physical exercises often, by comparing the changes of their high speed motion test before and after 8 years. The tests included analysis of motion in 15-second stationary step motions and muscle strength measurements of hip flexion in sitting position. The motions of 8 middle aged subjects were videotaped with a video camera operating at 60 Hz. The changes of perpendicular displacements, step rate, velocity, and coefficient of variation in the stepping motions were calculated and a comparative study was done between now and 8 years ago. Only little change could be found in body weight both men and women, which shows that constant and periodical exercises could prevent them from becoming obesity. Muscle strength increased in most of the subjects, and it is only a small gap among those whose muscular strength decreased compared with 8 years ago. Although step rate of the stepping motions was slightly decreased, perpendicular displacement in its motion was significantly increased. Velocity of leg motion in 5 of the subjects was increased. Spatial stability of motion in the stepping motions was significantly improved in most of the subjects. And also, time stability of motion in some of the subjects was improved. According to this study, it was suggested that constant and periodical sport activities could improve as well as maintain velocity and stability of motion of body movements.
