Article

This study compared head kinematic responses and step latency following an
anteriorly directed postural perturbation between two groups (Young, mean age
27.39; Elderly, mean age 71.9). We further attempted to demonstrate, for the
first time, a positive linear relationship between sagittal plane head angular
velocities and stepping responses in both groups. It was hypothesized that the
Elderly would demonstrate higher head angular velocities and greater step
latencies than the Young. We also hypothesized that a positive linear
relationship would show that, following a perturbation, trials where head angular
velocity was low yielded quicker step responses. Each participant experienced
three perturbations under five different visual conditions designed to alter
visual input and head/trunk coordination. Repeated-measures ANOVA was used, with
alpha set at 0.05. For each test condition, the Elderly consistently demonstrated
longer step latencies while exhibiting higher head angular velocities. For each
group, a positive linear relationship was shown between the two dependent
variables (Young: r=0.86; Elderly, r=0.84). During a postural perturbation, as
head angular velocity increased, stepping responses were delayed.

Langue : ANGLAIS