Article

Although gaze during adaptive gait involving obstacle crossing is typically
directed two or more steps ahead, visual information of the swinging lower-limb
and its relative position in the environment (termed visual exproprioception) is
available in the lower visual field (lvf). This study determined exactly when lvf
exproprioceptive information is utilised to control/update lead-limb swing
trajectory during obstacle negotiation. 12 young participants negotiated an
obstacle wearing smart-glass goggles which unpredictably occluded the lvf for
certain periods during obstacle approach and crossing. Trials were also completed
with lvf occluded for the entirety of the trial. When lvf was occluded
throughout, foot-placement distance and toe-clearance became significantly
increased; which is consistent with previous work that likewise used continuous
lvf occlusion. Both variables were similarly affected by lvf occlusion from
instant of penultimate-step contact, but both were unaffected when lvf was
occluded from instant of final-step contact. These findings suggest that lvf
(exproprioceptive) input is typically used in an online manner to control/update
final foot-placement, and that without such control, uncertainty regarding foot
placement causes toe-clearance to be increased. Also that lvf input is not
normally exploited in an online manner to update toe-clearance during crossing:
which is contrary to what previous research has suggested.
CI - Copyright (c) 2012 Elsevier B.V. All rights reserved.

Langue : ANGLAIS