Limited hip extension mobility has been proposed as a possible cause of both increased anterior pelvic tilt and subsequent exaggerated lumbar lordosis during walking and running. The purpose of the present study was to examine the coordinated sagittal plane kinematic patterns of the hip and pelvis during walking and running in a substantial group of adult recreational runners. The kinematics of 73 healthy adult runners (age: 34+/-11years) were examined on an instrumented treadmill at self-selected walking and running speeds using a three-dimensional motion capture system. Although stride length increased considerably from walking to running, the range of hip extension utilized during running was not significantly greater than that during walking. Thigh extension and anterior pelvic tilt were significantly greater during running than walking. Also, a significant positive correlation was found between hip extension and anterior pelvic tilt during both walking and running, indicating that anterior pelvic tilt was greater in subjects that displayed reduced utilized peak hip extension. Thus, compensations for the increased stride length during running seem to occur at the pelvis, and presumably in the lumbar spine, rather than at the hip. Considering the association between anterior pelvic tilt and lumbar lordosis, the present findings may have clinical relevance regarding the prevention and treatment of hamstring injuries and of injuries to the lumbar spine.