Assessment of postural stability using centre of Pressure and knee progression during dynamic gait

Abstract

One of the major goal of human walking is controlling precise movement of the body i.e. to stay upright while advancing the step. On each foot, the ground reaction force (GRF) reflects that control. Typical walking involves a synchronized change in the pressure beneath the foot i.e. Center of Pressure (COP) according to the change in the knee angle. This study investigates the knee flexion characteristics with the change in COP because of foot roll over and stepping and its role in posture stability. This paper presents the estimation of synchronized correlation between the change in knee angle and COP. With the advancement of COP below the foot region the flexion angle of the knee reaches to its maximum value from toe off till heal strike. The time taken by the right knee to reach to its maximum is ∼20%±10% less than COP travelled along the left foot irrespective of the speed. Similarly with the left knee which takes ∼50%±9% less time during damping to reach to its maximum under normal speed. This percentage of time increases as the velocity decreases. This time helps in controlling the dampness and swiftness of the knee joints. For the postural stability this % of time must be in the optimal limit. The second parameter considered here for postural stability is lateral symmetry which must be under ∼−10 mm for right handed.