Effects of Cervical Motion Restriction on Wheelchair Propulsion Velocity and Upper-Limb Kinematics in Healthy Individuals.

Forward head flexion during wheelchair propulsion has been suggested to compensate for reduced trunk muscle strength in individuals with spinal cord injury, but the influence of restricting head-neck movement on propulsion remains unclear. This study examined wheelchair propulsion under cervical fixation and non-fixation conditions. Fourteen healthy young men (20.7 ± 0.5 years) performed 5 m wheelchair propulsion under both conditions. Propulsion was recorded with a smartphone camera, and coordinates of the left ear, shoulder, elbow, and wrist were extracted using You Only Look Once version 7 (YOLO v7) to calculate upper-arm segment and elbow angles and angular accelerations. Analysis focused on the first three propulsion cycles after movement onset. Propulsion velocity showed a significant main effect of measurement point, but neither the main effect of cervical fixation nor the condition-by-point interaction was significant. Velocity increment differed significantly among measurement intervals, whereas the condition effect and interaction were not significant. Cervical fixation was associated with a smaller minimum upper-arm segment angle and greater upper-arm segment excursion, maximum elbow angle, and elbow range of motion. A significant condition-by-cycle interaction was found for minimum elbow angle, with a smaller angle under fixation during the first cycle. Minimum upper-arm segment angular acceleration in the flexion direction also differed among cycles. Thus, cervical fixation was associated with changes in upper-limb kinematics, but a statistically significant change in propulsion velocity was not demonstrated. These preliminary findings provide a basis for future studies in wheelchair users and athletes.