Abstract
The purpose of this study was to determine the effects of exercise position and load condition during isotonic exercise on the muscle activity of the gluteus maximus and gluteus medius muscles. Twelve healthy subjects with a mean age of 23.7 years participated in this study. Isotonic exercise for both hip abduction and hip extension were performed under the following four load conditions; no-load, loads of 2%, 4%, 6% body weight using ankle weights, and two exercise positions; side-lying and standing for hip abduction, and prone and standing for hip extension. During isotonic exercise for hip abduction, both the mean %RFEMG and peak %RFEMG of the gluteus maximus and gluteus medius muscles were significantly increased with an increase in load in the side-lying position, but only the mean %RFEMG were significantly increased in the standing position. Muscle activities of the gluteus maximus and gluteus medius muscles in the standing position were lower than those in the prone position during isotonic exercise for hip extension. These findings suggest that the weight loads during isotonic exercise were less effective for the gluteus maximus and gluteus medius muscles in the standing position.
