Lower extremity range of motion in the recreational sport runner.

The purposes of this study in the recreational runner were to describe and compare lower extremity sagittal range of motion and vertical body displacement for slow and fast paces during treadmill and overground running, and to compare timing of the running phases at the two paces. Vertical displacement of the body, and flexion and extension of the hip, knee, and ankle were measured with a motion analysis system at 200 hertz as the subjects self-selected the two paces. No statistically significant differences were seen when comparing sagittal motion on a treadmill with overground running. Statistically more vertical displacement during overground running was recorded when compared with treadmill running. Peak vertical force was near midstance when the ankle, knee, and hip approached maximum flexion. Results demonstrated that during a slow pace the approximate arcs of motion were: ankle, 50 degrees; knee, 95 degrees; and hip, 40 degrees. During running at a fast pace, the hip required more extension in early swing; the hip and knee required more flexion in middle and late swings. The fact that ankle motion did not change with the different speeds gave credence to the belief that push-off, or toe-off, is not the source of power in running.