Stepping responses made by elderly and young female adults to approach and accommodate known surface height changes

Falls on stairs, kerbs and footpaths are a major cause of morbidity in older female adults. This investigation examined the stepping responses made by 48 elderly (mean age 67 years, S.D. 5.4 years) and 48 young (mean age 20 years, S.D. 2.4 years) healthy, community-dwelling adult females to approach and accommodate known surface height changes. The surface was designed to simulate an object like a kerb or step in the walking path. For ascent, the surface was 9 m long (height, 15 cm) with a 13 m ground-level approach. For descent, it was 15m long (height, 15 cm) with a 7 m ground-level departure. These tasks (particularly descent) perturbed the gait of the elderly more than the young. The elderly exerted more control or were more cautious. They made earlier and larger step adjustments (p<.05), primarily employed a short step crossing strategy (elderly, 60%; young, 19%), exhibited less footfall variability (p<.05), moved slower across the step (p<.001) and spent more time in double foot support while crossing the step. In descent, the elderly preferred to land on the forefoot (p<.001). In both conditions, the elderly placed the feet closer to the step and cleared it by a lesser margin. Step descent appears to be particularly hazardous for older females since foot clearances were small and foot placement was closer to the step.