Peripheral visual cues affect minimum-foot-clearance during overground locomotion.
The importance of peripheral visual cues in the control of minimum-foot-clearance during overground locomotion on a clear path was investigated. Eleven subjects walked at their natural speed whilst wearing goggles providing four different visual conditions: upper occlusion, lower occlusion, circumferential-peripheral occlusion and full vision. Results showed that under circumferential-peripheral occlusion, subjects were more cautious and increased minimum-foot-clearance and decreased walking speed and step length. The minimum-foot-clearance increase can be interpreted as a motor control strategy aiming to safely clear the ground when online visual exproprioceptive cues from the body are not available. The lack of minimum-foot-clearance increase in lower occlusion suggests that the view of a clear pathway from beyond two steps combined with visual exproprioception and optic flow in the upper field were adequate to guide gait. A suggested accompanying safety strategy of reducing the amount of variability of minimum-foot-clearance under circumferential-peripheral occlusion conditions was not found, likely due to the lack of online visual exproprioceptive cues provided by the peripheral visual field for fine-tuning foot trajectory.
Graci
Valentina
V
Vision and Mobility Laboratory, Bradford School of Optometry and Vision Science, University of Bradford, Bradford, UK. v.graci@bradford.ac.uk
Elliott
David B
DB
Buckley
John G
JG
D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D003463:Cues; D004777:Environment; D005135:Eye Protective Devices; D005260:Female; D005528:Foot; D006801:Humans; D008124:Locomotion / Q000502:physiology*; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology; D014794:Visual Fields / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*; D016138:Walking / Q000502:physiology*