Foot clearance during stair descent: effects of age and illumination

It is likely that many stair accidents result from a trip during stair negotiation, yet few studies have examined the exact nature of balance loss during falls on stairs. The purpose of this stud), was to investigate potential age-related differences in the minimum clearance of the foot during stair descent, and to explore whether the minimum foot clearance was affected by the available ambient lighting. Twelve young at:105 (24 +/- 3.3 years) and 10 older adults (73.7 +/- 1.9 years) participated in the study. The older adults had significantly geater within subject coefficients of variation compared to the young adults, and had a significantly larger number of minimum foot clearances which fell bellow 5 mm. While the young subjects increased their minimum clearance by 3.6 mm on average in response to a decrease in ambient lighting the older adults maintained the same clearance over all stairs except one. These results suggest that the variability of minimum foot clearance. and lack of precautionary increases in foot clearance under reduced lighting may contribute to falls on stairs by the elderly. (C) 2004 Elsevier B.V. All rights reserved.