Abstract
Hip and knee joints, while walking, make three-dimensional movements comprising X, Y, and Z axes. Angular changes while walking are repre-sented by treatment with a microcomputer using three electric potentiometers orthogonal at these three axes. The time passed from one heel contact to the next is normalized to 100%, and the angular change within ten seconds is over-written (normal hip joint flat gait). Stance phase and swing phase have predominantly those movements in the direction of extension, adduction, and internal rotation and in the direction of flexion, abduction, and external rotation, respectively (normal knee joint flat gait). The stance phase has small movements, with increased movements proportional to the rate of gait; while the swing phase has a peak of flexion, abduction, and external rotation (joint angles up and down stairs). Both hip and knee joints have more variations in movement (hemiplegic patients). Angular changes are represented by scissor's gait, circumduction gait, stiff legs, etc., in addition to differences between left and right movements (ataxia). Hip joint angle is most stable at 90 steps/m, with more variations at 40, 60, and 120 steps/m, which makes an index to the determination of optional rate of gait.
