Comparison of Muscle Activity in Young People and Seniors During Hip Adduction and Abduction Movements According to Backrest Angle

The purpose of this study was to analysis patterns of changes in muscle activity and subjective assessment at various backrest angles during lower-limb rehabilitative exercises across different age groups to determine the appropriate backrest angles during exercise. Elderly people experience difficulties in normal walking due to their reduced muscle strength, balance, and flexibility caused by aging. Although equipment has been developed for muscle strengthening and rehabilitative exercises, studies on exercise postures and chair backrests are relatively insufficient. In this study, participants performed hip adduction and abduction rehabilitative exercises. Electromyogram test and a subjective questionnaire survey were conducted for 15 healthy adults in their 20s and 4 healthy elderly persons aged 65 years or older. Differences in muscle activity level according to backrest angle were observed. A significant difference in angle preference was found between young and old participants (p < 0.05). Results of this study may be used as ergonomic data to develop rehabilitative exercise equipment.