Article

Adapting to a predictable moving surface such as an escalator is a crucial part
of daily locomotor tasks in modern cities. However, the associated biomechanics
have remained unexplored. In a gait laboratory, fifteen young adults walked from
the ground onto a moving or a static surface while their kinematic and kinetic
data were obtained for calculating foot and pelvis motions, as well as the angles
and moments of the lower limb joints. Between-surface-condition comparisons were
performed using a paired t-test (alpha = 0.05). The results showed that
anticipatory locomotor adjustments occurred at least a stride before successfully
walking onto the moving surface, including increasing step length and speed in
the trailing step (p < 0.05), but the opposite in the leading step (p < 0.05).
These modifications reduced the plantarflexor moment of the trailing ankle needed
for stabilizing the body, while placing increased demand on the knee extensors of
the trailing stance limb. For a smooth landing and to reduce the risk of
instability, the subjects adopted a flat foot contact pattern with reduced
leading toe-clearance (p < 0.05) at an instantaneous speed matching that of the
moving surface (p > 0.05), mainly through reduced extension of the trailing hip
but increased pelvic anterior tilt and leading swing ankle plantarflexion (p <
0.05). The current results provide baseline data for future studies on other
populations, which will contribute to the design and development of strategies to
address falls while transferring onto moving surfaces such as escalators.
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Langue : ANGLAIS