Previous studies4–6,14 have demonstrated the effectiveness of passive stretching for increasing hip extension ROM in subjects did not have pain that interfered with walking or running and who had presumed hip flexor muscle tightness. To our knowledge, however, no one has reported on the effect of a program of active stretching of the hip flexors for patients with pain due to disorders affecting the low back or lower quarter. The purpose of our study was to determine if there is a difference between active and passive stretching for increasing hip extension ROM in subjects who have a lower-extremity injury or low back pain and who presumably have hip flexor muscle tightness.