Measures of Risk of Tripping and Minimum Foot Clearance When Crossing an Obstacle

A gait experiment was designed to examine the risk of tripping by analyzing subjective and objective data. The experimental considered both lighting conditions and obstacle conditions. Obstacle conditions were subdivided by obstacle height, type and color contrast. Lighting conditions included normal and dimmed conditions. Six male subjects were recruited. They walked on a walkway and crossed an obstacle. They gave a rating of perceived risk of tripping (PRT) on a five-point scale from 1 no risk to 5 extremely high risk, both before and after the walk. A rating of gait disturbance (RGD), also on a five-point scale, was recorded by a researcher after the subject had overcome the obstacle on the walkway. The minimum foot clearance (MFC) of both the leading and the trailing foot when crossing the obstacle were calculated. The results indicated that obstacle height (p<0.0001) had a significant effect on the PRT both before and after the walk. The effect of obstacle height on the RGD was also significant (p<0.0001). The obstacle type was significant (p<0.0001) on the MFC of both the leading and the trailing foot. PRTbefore was significantly correlated with MFC of lead foot (p<0.01). PRTafter was significantly correlated with MFC of lead foot (p<0.0001), and MFC of trailing foot (p<0.0001). The results of this study provide information for studying the gait and subjective perception when crossing an obstacle, and provide a certain reference for countermeasures to reduce the risk of tripping when crossing an obstacle.