Abstract
[Purpose] Electromyography (EMG) was used to examine gluteus medius and maximus activities with the hip in sustained extension and abduction. [Subjects and Methods] Subjects were 10 healthy male persons, mean age of 24.4 years. The gluteus medius and maximus overlap area was confirmed with ultrasonic imaging. EMG activity of each muscle was measured during a change in lower limb weight load on the measurement side with the hip in sustained extension and abduction. [Results] Activities of the gluteus medius posterior fibers, overlap area, and gluteus maximus upper fibers increased with hip extension, and activities of the gluteus medius and overlap area increased with hip abduction. [Conclusion] Gluteus medius posterior fibers were identified in the area extending from the ventral side of the angle between the lines that connect the vertex of the iliac crest and greater trochanter, and the posterior superior iliac spines and greater trochanter. The gluteus maximus upper fibers were not involved in hip abduction.
