Age-related slip avoidance strategy while walking over a known slippery floor surface.

When confronted with impending slip/fall situations, gait parameters are adjusted accordingly to avoid slipping. This study was conducted to assess age-related slip avoidance strategy by measuring gait parameters and muscle activity characteristics of the lower extremities (hamstrings, calves, and quadriceps) of both young and older participants while ambulating successfully over a known slippery floor surface. Fourteen younger and 14 older adults participated in this study. First, a baseline measure was collected to study normal gait prior to any exposure to slipping. A second measure was collected following a slip from a contaminated floor surface, but before the initiation of a second slip, where the participants were able to view the contaminated surface before traversing it. The results indicated that there were significant gait parameter differences between normal-dry walking conditions and contaminated-slippery walking conditions. In general, participants (young and old) reduced step length, friction utilization, and heel contact velocity from normal gait to adjusted gait conditions. Furthermore, results also indicated that there were differences in gait parameters and muscle activity characteristics between the two age groups for both a normal gait condition and a gait condition requiring adjustment. Findings suggested that older individuals required an additional step to properly adjust gait for a contaminated walking surface.

Effects of planar and non-planar driver-side mirrors on age-related discomfort-glare responses.

In this study, we evaluated subjective nighttime discomfort-glare responses on three different types of planar and non-planar driver-side mirrors on two age groups. Fifty-six individuals (28 young [18-35 years] and 28 old [65 years and over]) participated in this experiment. Subjective discomfort-glare rating scores on three different types of driver-side mirrors were assessed utilizing De Boer's rating scale in a controlled nighttime driving environment (laboratory ambient illuminant level-l lux with headlight turned off). Three driver-side mirrors included planar "flat mirror": radius of curvature 242650.92 mm, reflectivity 0.60114, and surface reflectance 0.60568; "curved mirror": radius of curvature 1433.3 mm, reflectivity 0.21652, and surface reflectance 0.58092; "blue mirror": radius of curvature 1957.1 mm, reflectivity 0.25356, and surface reflectance 0.54585. The results indicated that with the same glare level (as measured by angle of incidence and illuminance in front of the eyes), older adults reported worse feelings of glare than their younger counterparts. Furthermore, the results indicated that both young and older adults reported worse feelings of glare for planar driver-side mirror than non-planar driver-side mirrors. These results suggest that older adults' criterion of discomfort-glare is more sensitive than their younger counterparts, and importantly, the non-planar driver-side mirrors can be beneficial in terms of reducing nighttime discomfort-glare for both the young and the elderly.