Comparing Running-Specific and Traditional Prostheses During Running: Assessing Performance and Risk

A. BACKGROUIND

Current knowledge and understanding of individuals with lower extremity amputations (ILEA) when running are limited with respect to biomechanical performance and injury risks. ILEA are able to run with both running-specific prostheses (RSPs) and traditional prostheses; however, direct comparisons of subjects running with each of these prosthetic designs do not exist. The reported literature examining one design or the other often do not have participants running at the same velocities. Additionally, when running velocities are similar between studies, the same variables are rarely investigated. This makes comparisons between RSPs and traditional prostheses exceedingly difficult, and drawing conclusions on both performance and injury risk is virtually impossible. Furthermore, no ILEA running studies to date have investigated muscle activities, nor have running simulations of musculoskeletal models been generated. These major gaps in research substantially limit the understanding of both performance and injury risk of ILEA running with different prosthetic designs. Gaining this knowledge will directly inform clinicians and administrators within the Department of Defense and Veterans Administration systems on prosthesis prescription for running at a range of speeds as well as for return to duty scenarios. Therefore, the proposed study will utilize motion capture, muscle activity, and musculoskeletal modeling techniques to directly compare performance and injury risks of ILEA running with both RSPs and traditional prostheses across a range of speeds. The investigators will also capture an able-bodied control group for normative comparisons. In doing so, this project directly attends to the OPORA's goals and needs at multiple levels.

B. RESEARCH STRATEGY:

Subjects Twelve subjects with unilateral transtibial amputations will be recruited from the military, veteran, and civilian populations. Twelve able-bodied sex, age, height, and weight-matched subjects will serve as a control group to provide normative data for comparison. All subjects must provide their informed consent prior to beginning any portion of the study and will have the option to discontinue the study at any time without penalty. All subjects must complete the Physical Activity Readiness Questionnaire (PAR-Q) prior to beginning the experiment. If subjects fail this questionnaire (by responding "yes" to any of the 7 questions), they will not be allowed to participate in the study until they provide documentation from a physician clearing them to participate.

Experimental Procedures A randomization computer program will determine the order of prosthetic foot conditions (RSP or traditional) for the ILEA subjects. All subjects (Controls and ILEA) will undergo 3D running analysis on an instrumented treadmill. A motion capture system will collect kinematic data (i.e. limb positions; joint angles, velocities, accelerations) at 200 Hz from reflective markers placed on specific body landmarks. On the amputated limb, the shank cluster will be placed laterally on the socket and a marker will be placed at the distal tip of the socket to define the long axis of the residual shank segment. For the RSP conditions, eight additional markers will be placed on the prosthesis keel. The marker on the most acute point of the prosthesis will define the prosthetic limb "ankle" joint. For the traditional prosthesis conditions, markers will be placed similarly to the intact foot.