FRONTAL PLANE LOWER LIMB KINEMATICS CHANGE AT TOE-OFF FOR LOADED WALKING TO MAINTAIN MEDIAL-LATERAL GAIT STABILITY

Abstract

The purpose of the study was to examine the impact of carrying backpack loads on the medial-lateral gait parameters. Seventeen primary school boys walked on an instrumented treadmill with 10%, 15% and 20% bodyweight loads. At the instance of toeoff of the ipsilateral leg, the whole body weight is supported by the contralateral leg. The shift to single leg support may render the gait unstable. However, a three-dimensional kinematic analysis revealed that at toe-off, the body adopts certain frontal plane gait changes at the knee to control the moment induced in the frontal plane by the quasi-force couple of the gravitational force on the centre of mass (COM) and the vertical normal reaction force on the contralateral supporting leg. For the loaded conditions, since the magnitude of the gravitational force and the normal reaction force increases because of the additional backpack load, the increase in the magnitude of the quasi-force couple is regulated by a change in knee kinematics.