Conclusions

Abstract

When standing on both feet, the load exerted on the knees is the weight of the supported part of the body, i.e. the weight of the body minus the weight of the lower legs and feet. But the knee is under much more stress during gait. In these conditions it eccentrically bears a heavier mass: the body minus only the supporting lower leg and foot. Furthermore, the displacements of the body segments through space provoke forces of inertia which are added to the body weight. If the weight of the body segments, their centre of gravity, and their displacements are known it is possible to determine the successive positions of the centre of gravity of the part of the body supported by the knee and hence to calculate the forces of inertia due to accelerations of this part.