Age-related changes in gait when negotiating a raised surface

This research focuses on lower limb motion while negotiating a raised surface during gait and identifies the differences between young and elderly individuals. The gait of six healthy young females and six healthy elderly individuals were analysed using a motion analysis system under three conditions; unobstructed, stepping-on and stepping-off a raised surface. During stepping-on the clearance over the step edge was approximately 10 cm. The elderly showed significantly lower lead and trail foot clearance. Foot clearance over the step edge during stepping-off, however, was very low compared to the stepping-on condition (2.4 cm for the lead foot and 1.5 cm for the trail foot). The elderly cleared the step by a significantly higher margin suggesting a safety mechanism adopted by the elderly during obstacle negotiation. In negotiating a raised surface elderly individuals appear to employ a "non-optimal" foot placement strategy in which compared to young subjects the trail foot is placed a long way from the edge of the step. The elderly subjects allowed very little correction time and little latitude in foot placement beyond the edge of the step suggesting that the approach to the obstacle may be a critical determinant of safety.