Abstract
[Purpose] The purpose of this study was to investigate the effects of physical activity on the muscular strength of the lower extremities of mentally retarded adults. [Subjects] The subjects were ten adults with mental retardation, residents of a special institution, who took part in an aerobic and strength exercise program and ten others who did not perform any exercise for 24 weeks. [Methods] Participants in the exercise group performed the combined exercise therapy at 55–69% HRmax for an hour 3–4 days a week for 24 weeks. Leg muscular strength was measured before and after the training. The paired t-test was used analyze the difference between before and after training. [Results] The exercise group showed significantly improved leg muscular strength. [Conclusion] The findings imply that the physical activity over a long period has a significant effect on the muscular strength of the lower extremity of adults with mental retardation.