Effects of visual deprivation on stability among young and older adults during treadmill walking

The purposes of this study were 1) to investigate the effect of visual deprivation on stability during treadmill walking in older and young adults, and 2) to examine if such an effect differs between age groups. Under the protection of a safety harness, 10 young (23.20 ± 2.44 years) and six older adults (67.83 ± 2.48 years) participants performed two 90-s walking trials (one with eyes open or EO and the other with eyes closed or EC) at their self-selected treadmill walking speeds determined during EO walking. The step length, step width, foot landing angle, the duration of stance phase, and cadence were calculated from the foot kinematics collected for each participant. The variability (i.e., the standard deviation) of step length, step width, foot landing angle, and the duration of stance phase was also calculated to quantify the stability during walking. Our results revealed that both young and older adults took a cautious gait pattern during EC walking, as evidenced by the shorter step length, smaller foot landing angle and shortened stance phase compared to EO walking. Under both visual conditions, older adults exhibited shorter step length and smaller foot landing angle than their young counterparts. No age-related differences were observed for the measurements of variability (i.e., the quantification of stability) while the variability measurement of all four variables was higher during EC walking than during EO walking for both age groups. Findings from this study could provide insights into the mechanisms of how visual information affects stability during gait.