Motorized Prostheses for Lower-limb Amputees

The investigators will assess biomechanical and functional mobility outcomes in individuals with unilateral, above-knee amputations using different knee/ankle configurations of a lightweight powered prosthesis and different volitional controllers in individuals with unilateral, above-knee amputations.

Our inclusion criteria will be * Above-knee amputation * K2/K3/K4 ambulators * At least 18 years old * At least one year since amputation * At least six months since the definitive prosthesis fitting * Currently prescribed and using a mechanically passive or microprocessor-controlled prosthesis Our exclusion criteria will be * Over 350 lbs. body weight, the weight limit for our safety suspension systems * Cognitive deficits or visual impairment that could impair their ability to give informed consent or to follow simple instructions during the experiments * Pregnant women due to elevated safety concerns for this population * Co-morbidity that limits their ability to participate in the study protocol (e.g., stroke, pacemaker placement that would interfere with the powered prosthesis, severe ischemia, cardiac disease, etc.) * Adults who are unable to consent * Individuals who are not yet adults (infants, children, teenagers) * Individuals who use a wheelchair for mobility both outdoors and indoors because they may not be able to perform the necessary activities with their passive prosthesis or the powered prosthesis * Prisoners, due to concerns with informed consent