Turning Strategies While Walking on an Omnidirectional Treadmill With Virtual Reality

Omnidirectional treadmills with virtual reality (ODTVR) offer a promising alternative for training complex locomotor tasks that require changes in direction, but their effects on locomotion remain unclear. This study examined the impact of a motorized self-paced ODTVR setup on axial body segment coordination and spatiotemporal gait parameters during a turning while walking task. Kinematic data of twenty healthy young adults were collected as they walked and turned in different directions and under three conditions (ODTVR, as well as omnidirectional treadmill (ODT) without VR, and overground (OVG) without VR). Results revealed a similar sequence of segment reorientation across conditions, which was initiated with the head, followed by the thorax, pelvis and heading. However, earlier onsets (242-250 ms), and marginally smaller segment reorientation amplitudes (2-3 $^{\circ }\text {)}$ , were observed in the ODTVR vs. other conditions. Slower walking speeds and shorter step lengths were generally observed in the ODT vs. OVG condition, with further decreases in the ODTVR condition. Standardized questionnaires revealed that ODTVR walking was perceived as non-anxiogenic and easy to use, but that it induced a moderate sense of presence and elevated simulator sickness. Findings indicate that alterations in body segment coordination during ODTVR walking, while subtle, are primarily caused by VR, but walking speed and step length were affected by both the ODT and VR. While the differences induced by ODTVR walking should be taken into consideration, the present findings support its use for clinical and experimental purposes. They also highlight the importance of accounting for habituation and user experience in future applications.