Virtual Reality-Induced Changes in Lower-Limb Kinematics During Obstacle Crossing

Obstacle crossing is a fundamental, yet complex, motor task commonly observed in daily life and occupational settings. Nevertheless, accurately replicating real-world crossing strategies in a virtual reality environment (VRE) remains challenging, potentially limiting the broader application of virtual reality (VR) in these domains. In this context, this study compared individuals’ gait and lower-limb kinematics during their performance of obstacle crossing in a real environment (RE) and a VRE to determine whether the latter alters their crossing behavior. Participants completed obstacle-crossing tasks over three obstacles (low: 100 mm, middle: 200 mm, and high: 300 mm) in both environments. Our results indicated that the participants’ overall crossing speed was reduced in the VRE (low obstacle: −9.0 cm/s; middle obstacle: −6.0 cm/s; high obstacle: −2.0 cm/s). Specifically, we observed that in the VRE, the leading leg exhibited greater lower-limb flexion (low obstacle: +13.8°; middle obstacle: +11.1°; high obstacle: +8.2°), which resulted in a higher toe clearance (low obstacle: +76.4 mm; middle obstacle: +40.0 mm; high obstacle: +23.5 mm). In addition, the horizontal distance from the peak vertical position was extended (low obstacle: +93.1 mm; middle obstacle: +79.0 mm; high obstacle: +73.8 mm). For the trailing leg, a trend similar to that of the crossing leg was observed under the VRE low-obstacle condition; however, with increasing obstacle height, the VRE showed smaller lower-limb flexion (high obstacle: −12.7°) and toe clearance than the RE (middle obstacle: −68.2 mm; high obstacle: −115.2 mm). These findings provide insight into gait adaptation in virtual contexts and support the design of more effective VR-based interventions for rehabilitation and fall prevention.