Investigation of the Biofidelity of the MIL-Lx Foot

Foot/ankle injuries from frontal automobile collisions are frequent and debilitating. While postmortem human subject testing is advantageous as it provides realistic injury responses, it is expensive, highly variable and does not collect internal loading data. Anthropomorphic Test Devices, however, collect load data and are easily used in industry. A biofidelic foot is essential for correctly transmitting load to the tibia where lower leg injury risk is assessed. This study combined Post-Mortem Human Subject feet with an Anthropomorphic Test Device tibia to examine the response of feet while collecting industry-relevant metrics. The Military Lower Extremity, six post-mortem human subject lower legs, and six adapted specimens containing the Military Lower Extremity “tibia” shaft and Post-Mortem Human Subject feet were equipped with an instrumented boot and axially impacted at 5 m/s, representing a frontal automotive collision. No significant differences were found on the plantar surface among all specimens, suggesting this may be a feasible method of evaluating foot response. Significant differences were found in the proximal tibia load cells when comparing the adapted specimens with the Military Lower Extremity, suggesting its foot is overly stiff. These data can be used for redesigning the Anthropomorphic Test Device foot, thus improving lower limb safety assessments.