Foot/ankle roll-over characteristics for different joint alignments of the ankle-foot orthosis(AFO) during level walking

This study investigated foot/ankle roll-over characteristics for different joint alignments of the ankle-foot orthosis(AFO). Seven volunteers without any musculoskeletal or foot problems participated in motion analyses. To obtain roll-over shape of the ankle-foot complex, we used trajectories of ankle and knee joints and the center of pressure(COP) between initial contact(IC) and opposite initial contact(OIC). After the roll-over shape was determined for each data, it was represented by a circular arc using the least-square method. Results showed that for the more dorsiflexed AFOs, the more distally the roll-over trajectory moved at initial contact. Also, we found that the radius of curvature significantly increased and the center of roll-over shape moved posteriorly and superiorly in dorsiflexed AFOs. Present results might provide a better understanding for the proper alignment of the orthotics as well as a single roll-over shape during walking.