Kinematics of Ewing Amputees

The agonist-antagonist myoneural interface (AMI) construct, known as the Ewing amputation at the trans-tibial level, has been shown to create a bi-directional neural communication platform as a means of controlling and interpreting proprioceptive feedback from a prosthetic joint. In AMI constructs, agonist-antagonist muscles are mechanically coupled within the residual limb, and volitional contraction of an agonist passively stretches that muscle's antagonist. The natural neural responses from muscle spindles within both muscles are then interpreted by the central nervous system as sensations of joint position and speed, associated with movement of the prosthesis. The aim of this research protocol is to evaluate the electromyographic and kinematic patterns of participants who have undergone unilateral lower extremity Ewing Amputation in order to determine how similar their residual limb data is when compared to their intact limb data. A secondary aim of this research may include comparison of the Ewing participant cohort's biomechanical patterns to a similar cohort of participants who have undergone standard amputation. The investigators hypothesize that the affected limb of patients with the Ewing procedure will demonstrate a pattern of electromyographic activation of their AMI constructs and kinematic data that recapitulates the pattern seen in their intact limb. The investigators secondarily hypothesize that the kinematic assessment of Ewing Amputation patients will demonstrate patterns that are significantly more physiologic than those witnessed in similar assessments of standard amputees.

Inclusion Criteria: * Unilateral lower extremity amputees * Greater than 12 months post-amputation procedure * Possession and use of a working prosthesis as determined by subject's ability to wear it for 8 hours daily * A stable, well-fitting socket as indicated by no prosthetic modifications within the prior 14 days and no plans to modify it within the following 30 days * Follow-up visit with their prosthetist within the past 3 months * The ability to walk independently without an assistive device * The ability to follow directions and communicate pain or discomfort Exclusion Criteria: * Patients beyond the stated age restrictions will be excluded * Patients who have any underlying neurologic, orthopedic, or cardiopulmonary impairment that affects their gait as assessed by the study clinician. * Patients with any medical or functional limitations preventing them from ambulating safely and independently without an assistive device. * Patients will be excluded who do not have a prosthesis