The purpose of this study is to perform a biomechanical study of a prototype prosthetic foot and evaluate if it provides a physiological generation of power at the ankle in transtibial amputees. The prosthetic foot is a prototype system that generates power via actuators (i.e. robotic system).

Subjects will be studied during level-ground walking. A camera-based motion capture system will be used to study the biomechanics of motion and evaluate if the pattern of ankle power generation by the prosthetic foot is physiological. In addition, the metabolic cost of ambulation will be monitored during walking at constant speed over a period of several minutes. The data will allow us to assess if the prosthetic foot leads to a decreased metabolic cost of ambulation compared to passive prosthetic feet.

Inclusion Criteria:

• weigh more than 200 lbs
• are high level ambulators corresponding to levels E to F of the Special Interest Group of Amputee Medicine (SIGAM) mobility grade
• have the ability to follow multi-step commands.

Exclusion Criteria:

• score level D on the SIGAM mobility grade
• have experienced 1 or more falls in the last month before the study
• have a residual limb length which does not allow for seven inches clearance of bracket attachment for the PowerFoot
• the residual limb must be stable in volume (no change in socket or socket padding in last 6 months) and without pain that limits function
• the sound-side (contralateral) lower extremity must be free of impediments that affect gait, range of motion, or limb muscle activity
• Any diagnosed cardiovascular, pulmonary, neurological, and/ or orthopedic conditions that would interfere with subject participation

Adults with history of traumatic unilateral transtibial amputation