Biomechanical Response and Physical Properties of the Leg, Foot, and Ankle

The anatomical dimensions, inertial properties, and mechanical responses of cadaver leg, foot, and ankle specimens were evaluated relative to those of human volunteers and current anthropometric test devices. Dummy designs tested included the Hybrid III, Hybrid III with soft joint stops, ALEX I, and the GM/FTSS lower limbs. Static and dynamic tests of the leg, foot, and ankle were conducted at the laboratories of the Renault Biomedical Research Department and the University of Virginia. The inertial and geometric properties of the dummy lower limbs were measured and compared with cadaver properties and published volunteer values. Compression tests of the leg were performed using static and dynamic loading to determine compliance of the foot and ankle. Quasi-static rotational properties for dorsiflexion and inversion/eversion motion were obtained for the dummy, cadaver, and volunteer joints of the hindfoot. Dynamic and impact tests were conducted with dummy and cadaver limbs to determine dynamic moment-angle response curves for the hindfoot joints. The testing indicates that passive and active musculature of the leg strongly influences response of the leg, foot, and ankle and suggests that future dummy designs should incorporate these effects. Synthesis of the volunteer and cadaver test results provides physical properties and response corridors of the foot, leg, and ankle for use in mathematical and mechanical models.