Transient change in standing posture after linear treadmill locomotion.

Postural sway was measured in 24 healthy subjects after running or walking with eyes open on a standard treadmill exerciser. The speeds of running and walking were set at 10 and 7 km/h, respectively, and locomotion was maintained for 7 min. The postural sway response was characterized by systematic forward displacement followed by gradual decay to baseline and was accompanied by self-motion perception. Mean fore-back postural after sway was significantly greater after treadmill running than after normal running. The aftereffects of treadmill walking were significantly less than those of treadmill running. The 6 subjects showing distinct forward postural sway after treadmill walking were instructed to walk on the treadmill with their eyes closed. After this, none of the 6 subjects felt self-motion perception and had no evidence of postural aftersway. These results clearly demonstrate that vision during treadmill locomotion plays an important role in evoking postural sway after treadmill locomotion. It can be inferred that somatosensory/motor signals may be stored during visual-somatosensory/motor conflict and that this stored information may evoke postural change and self-motion perception.