This is a model of a person with a unilateral transtibial amputation, and is adapted from the Gait2354.osim. The ankle, subtalar, and mtp joints were removed on the left side and replaced by a 1-DOF pin joint representing the prosthetic foot PF/DF. The left side tibia and fibula were replaced by a truncated tibia and fibula to represent the residual limb. An additional 6-DOF joint has been added between the residual limb and prosthesis socket segments. All muscles that cross the left ankle were removed except for the medial gastrocnemius, which was truncated and reattached at the middle of the residual limb.