Virtual Reality-Guided Reaching During Treadmill Walking Alters Dynamic Stability in People with Stroke

This study was designed to determine how goal-directed reaching during virtual reality (VR)-based treadmill walking affects dynamic balance in stroke survivors. Frontal-plane whole-body angular momentum (H) was used to quantify dynamic balance during gait.

Twenty individuals with stroke were enrolled in this study, and 16 were included in the analysis. Participants completed three blocks of a VR-based reaching task while walking on a treadmill after familiarization with both the VR system and treadmill walking. Kinematic data were collected using a markerless motion capture system (Theia3D, Theia Markerless Inc., Kingston, ON, Canada). Stride-level frontal-plane range of angular momentum (H_R) was computed, and segmental contributions to H were analyzed.

Frontal-plane H_R significantly increased during the preparatory, reaching, and post-reaching strides compared with non-reaching strides at three walking speeds. H_R was also greater for contralateral than ipsilateral targets. Segmental analysis revealed that the trunk and reaching arm contributed most strongly to changes in H. Reaching was also accompanied by changes in stride time, length, and width.

Reaching during walking imposes greater frontal-plane balance demands on stroke survivors, primarily through trunk and reaching-arm contributions. These findings support further investigation of task-specific, internally generated challenges as a component of VR-based gait rehabilitation.