Injuries to the lower extremities are among the most serious, non life threatening injuries occuring nowadays. In order to investigate and predict the occurrence of injuries, biofidelic research tools, like mathematical human body models are needed. The model of the lower extremity, presented here, includes active musculature, simulating bracing and fracture at certain injury thresholds found in literature. The model was validated with toe and heel impact tests on human specimens and volunteers and generally good agreement was found between experimental results and simulations. Using the model in a footwell intrusion simulation illustrates the prediction of fracture due to the contribution of active musculature in tibia loading.