GAIN OF MUSCLE TORQUE AT LOW AND HIGH-SPEED AFTER ISOKINETIC KNEE STRENGTHENING PROGRAM IN HEALTHY-YOUNG AND OLDER ADULTS

Low-speed isokinetic exercise has been recommended to exert a maximal contraction and produce greater muscle torque than high-speed exercise in young adults. The purpose of this study was to compare the effecti veness of low- and high-speed isokinetic exercise programs for increas ing muscle torque in young and elderly people. Twenty healthy elderly and 20 young subjects participated. The elderly subjects were divided into two groups. One group performed high-speed (300 degrees/s) isokin etic exercise training three times a week for the dominant-side knee e xtensor and low-speed (60 degrees/s) exercise for the non-dominant sid e for 6 weeks. The other group was trained using the reverse exercise regime. The training program for the young subjects was the same as th at for the elderly groups. All subjects had their knee extensor torque evaluated with an isokinetic test before and at 2-week intervals duri ng the training program. For young and elderly groups, both high- and low-speed isokinetic exercise training increased extensor torque in lo w- and high-speed tests. For the young group, low-speed exercise effec tively improved muscle torque at low and high speeds. The improvement in slow muscle torque was significantly greater than that in fast musc le torque. For the elderly subjects, high-speed isokinetic exercise pr oduced the greatest muscle torque at high speed in the first 2 weeks o f training, and demonstrated a sharp increase in muscle torque in the final 2 weeks. Low-speed exercise frequently caused knee stress and th e inability of some elder subjects to continue the exercises with maxi mal effort. Our findings indicate that high-speed exercise may be more appropriate for the elderly, and low-speed exercise may be more appro priate for younger people.