Lower-limb actions while running at different velocities

Electrogoniometers were used to measure step length, frequency and movements of hip, knee and ankle with increases in running velocity. Experienced distance runners ran on a horizontal treadmill at speeds ranging from 183 to 396 m/min. Runners increased velocity by increasing both step length and frequency; length playing a greater part at lower velocity and frequency playing a greater part as velocity approached 396 m/min. As velocity increased, hip extension showed little change while hip flexion increased markedly causing the amplitude to increase. During the swing phase, knee extension decreased while flexion increased with an increased amplitude. During the support phase, knee extension decreased while flexion increased with no change in the amplitude. Ankle flexion, extension and amplitude did not change with increase in velocity.