The purpose of this study was to investigate the muscle activities around hip joint during muscle strengthening exercises in closed kinetic chain. Ten healthy adult volunteers, 6 males and 4 females, with the mean age of 25.1 years old, participated in this study. Four muscles
gluteus medius, tensor fasciae latae, gluteus maximus and hip adductors, were analyzed with the rectified filtered electromyography (RFEMG) during only one legged standing and one legged standing with contralateral shoulder abduction or contralateral hip abduction or contralateral pelvic elevation. All RFEMG data were normalized to a percentage of the RFEMG voltage produced at the maximum isometric contraction (%RFEMG). In the results, the %RFEMG of hip abductors were significantly greater values in one legged standing with hip abduction and pelvic elevation than in only one legged standing, and became greater when resistance was applied in each exercise. No significant difference in the %RFEMG of hip abductors was found between only one legged standing and one legged standing with shoulder abduction, while the %RFEMG became greater when resistance was applied in shoulder abduction. Regarding hip adductors, the %RFEMG was low in each exercise. Our results suggest that the exercises in closed kinetic chain are effective for strengthening muscles around hip joint. © 1995, The Society of Physical Therapy Science. All rights reserved.