A Three-Dimensional Multibody Model of the Human Ankle-Foot Complex

In this work, a three-dimensional foot and leg model is proposed, which combines six rigid bodies and five kinematic pairs to produce an articulated system of four segments (toes, mid-forefoot, rearfoot and leg) with thirteen independent degrees-of-freedom. The model is described using a multibody dynamics formulation with natural coordinates and estimated anthropometric parameters. A massless link is used to model the anatomical offset between the talocrural and talocalcaneal joints, avoiding the inclusion of a specific rigid body to model the talus bone. The reliability of the model was tested through its application to the study of the kinematic and dynamic patterns of the human gait. A male subject was analyzed and his data compared with literature, enabling to attest the consistency and realism of the proposed model.