Article

Stair edges provide important visual cues for appropriate foot placement on the
stair and balance control during stair descent. Previous studies explored
age-related changes in stepping performance and balance control during stair
descent and included fit older adults. The present study investigates both age-
and frailty-related changes to stepping parameters and Centre of Mass (COM)
control during stair descent and how these measures are affected by visual
factors. Older adults were split into two groups containing participants with the
lowest (LROA, n=7) and highest (HROA, n=8) combined scores on tests of balance
and confidence to negotiate stairs. Data were also collected from younger adult
participants (YA, n=8). Kinematic data were collected from participants while
they descended stairs under combinations of ambient light (bright and dimmed) and
stair edge contrast conditions (high and low). A three (group) x two
(illumination)xtwo (contrast) ANCOVA was performed with average stair walking
speed as covariate. HROA cleared the stair edge vertically (p=0.001) and
horizontally (p<0.001) with less distance than LROA. Dimmed ambient light
resulted in decreased step length in HROA (p=0.006) compared to bright lighting.
High stair edge contrast led to reduced vertical COM acceleration variability in
HROA (p=0.009) and increased distance between COM and anterior base of support
(p=0.017) in LROA. YA increased horizontal foot clearance (p=0.011) when stair
edge contrast was high. We conclude that the aforementioned differences in
stepping behaviour shown by HROA may contribute towards an increased risk of
tripping and that high stair edge contrast has a beneficial effect on balance control in older adults.
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