Understanding How Powered Componentry Impacts K2-Level Transfemoral Amputee Gait

Inclusion Criteria: * Ages 18-95 * A unilateral transfemoral amputation * At least 6 months since definitive prosthesis fitting * Able to walk 50 meters (55 yards) with a prosthesis without the assistance of another person. * Medically cleared by physician to participate in study * English speaking Exclusion Criteria: * Weight greater than 250 pounds * Significant new injury that would prevent use of a prosthesis: The ability to consistently wear a prosthesis and perform activities of daily living and specific performance tasks is necessary to evaluate the relative benefits of the interventions. * Cognitive impairment sufficient to adversely affect understanding of or compliance with study requirements, ability to communicate experiences, or ability to give informed consent: The ability to understand and comply with requirements of the study is essential in order for the study to generate useable, reliable data. The ability to obtain relevant user feedback through questionnaires and informal discussion adds significant value to this study. * Significant other comorbidity: Any other medical issues or injuries that would preclude completion of the study, use of the prostheses, or that would otherwise prevent acquisition of useable data by researchers.