The Effects of AFO Heel Height and Stiffness on Gait

The proposed study evaluates the effect of ankle foot orthosis (AFO) heel height and stiffness on the forces and motion of the lower limb during over-ground walking in individuals who use an AFO for daily walking. Previous studies suggest that heel height and stiffness effect limb loading, but these data and the analysis techniques applied are limited. In this study, heel cushions with different height and stiffness's (4 conditions) will be placed in participants shoes and they will walk at controlled and self-selected speeds. Participants will also walk with their AFO as configured prior to enrollment, and with no AFO if possible. The proposed study will provide evidence that can be used by clinicians and researchers to align braces that most effectively improve function during every-day walking.

In this study the investigators to evaluate the effect of ankle foot orthosis (AFO) heel height and stiffness on the forces and motion of the lower limb during over-ground walking in individuals who use an AFO for daily walking. Previous studies suggest that heel height and stiffness effect limb loading, but these data and the analysis techniques applied are limited. Two groups of subjects with impairments below the knee, that result in functional deficits and require daily AFO use, will be recruited for this study. The first group will have unilateral deficits associated with musculoskeletal injury or disease (Group 1), and the second group will have bilateral or unilateral deficits associated with peripheral nervous system disease (Group 2). Lower limb forces and body motion will be assessed using computerized motion capture and force plates in the floor, as individuals walk over-ground. Small reflective markers placed on the participant's skin and force measuring plates in the floor will be used. Participants will walk with their clinically provided AFO, with added heel cushions of two different heights and stiffness's (4 conditions) at a controlled velocity and self-selected velocity. If able, they will walk without their AFO at a self-selected pace. Participants will be asked to provide information regarding their health condition and opinions of the conditions tested.