Avoiding trip- and slip-hazards in suburban footpaths by older adults: An immersive virtual reality experiment

Background Older people often fall due to trips and slips in daily life. This study aimed to elucidate the mechanisms of trip- and slip-hazard avoidance while walking through an immersive virtual reality suburban footpath. Methods Forty-six participants (71.8 ± 4.7 [65-84] years) wore an immersive head-mounted display (Oculus Rift S) and safety harness while walking on a split-belt treadmill (M-Gait). Participants walked on a virtual footpath while avoiding hazards including raised concrete slabs (trips) and puddles (slips) and as a secondary task collected apples. Foot-hazard contacts resulted in treadmill belt accelerations/decelerations to evoke balance loss. Hazard contact rates and gait kinematics were measured using Vicon motion capture. Results Participants contacted more trip-hazards (63.1%) than slip-hazards (22.2%) (p < 0.001). Trip-hazards were more frequently collided with by the trailing foot (56.9%) compared to the leading foot (16.7%) (p < 0.001). Trailing foot contacts for both trip- and slip-hazards caused greater balance disturbances compared leading foot contacts as measured by significantly changed extrapolated Centre of Mass (XCoM) and Margin of Stability (MoS). For trailing foot contacts, participants compensated better for trips by immediately increasing MoS compared to slips that decreased MoS indicating increased likelihood of balance loss. Conclusion On a suburban footpath, older adults often collided with trip-hazards with their trailing foot, which is typically beyond their visual field, while slip-hazards more commonly involved the leading foot. These insights can inform the development of fall prevention programs that better replicate everyday walking challenges.