KINES 300 Lecture Notes - Lecture 26: Ground Reaction Force, Anatomical Terms Of Motion, Inverted Pendulum

• School: American River College
• Department: Kinesiology
• Course: KINES 300
• Professor: Kiefer

Document Summary

Hip flexors (iliopsoas): concentric contraction to initiate leg swing because most important thing in pre-swing is to get ground clearance so hip needs to flex. Knee flexors: ground reaction force is behind knee so it creates knee flexion torque alone without knee flexors firing. Ankle plantar flexors: work less in pre-swing due to ground reaction force. The ankle plantar flexors store energy during the inverted pendulum movement. Stored energy transfers to kinetic energy when the foot is gradually lifted off ground. Ankle dorsiflexors: concentrically contract to clear ground. Hip extensors: concentric contraction to extend hip and reduce distance between heel and ground to prepare for landing. Mid-swing to early terminal swing: eccentric contraction to decelerate leg swing. Very end of terminal swing: concentric contraction to put leg on ground by flexing knee. Ankle dorsiflexors: isometric contraction to maintain ankle in neutral position and avoid foot drop.