The generation of torque in the horizontal plane at the foot-base during laterally directed manual exertions.

Two experiments were carried out to investigate the mechanisms by which both translational forces and a turning moment in the horizontal plane at the foot-base are transmitted by the lower limb during laterally directed manual exertions. The first used a force plate to measure forces and moments exerted by the feet separately or together in order to investigate the contribution of each foot to the moment. The second examined the role of flexors and extensors of the hip, knee and ankle in the transmission of torque. The results suggest that approximately half of the moment is generated by each foot exerting a translational force at a distance from, and in the opposite direction to, the other. The other half is by each foot exerting an individual torque upon the floor. It is suggested that biomechanical models of asymmetric exertion should take these mechanisms into account.