Comparison of 3-Dimensional Thorax and Upper-Extremity Joint Kinematics During Manual Wheelchair Propulsion Using Marker-Based and Markerless-Based Biomechanical Models

Marker-based motion analysis is the standard for evaluating human movement, yet it is time-intensive and requires extensive technical knowledge. Markerless-based motion analysis can simplify and expedite clinical biomechanics research, but its utility with unique populations, like manual wheelchair users, remains understudied. The purpose of this study was to compare 3-dimensional thorax and bilateral upper-extremity joint kinematics during manual wheelchair propulsion between criterion-standard marker-based and novel markerless-based biomechanical models. Fifteen young adult, manual wheelchair users propelled on a stationary roller while synchronized optical motion analysis cameras recorded 3-dimensional marker trajectory and 2-dimensional video data simultaneously. Statistical parametric mapping was used to evaluate kinematic differences between models. Pearson correlation and average root mean square were also used to explore the relationships and the magnitudes of observed differences between models. Significant differences in thorax and upper-extremity joint kinematics were observed between the models (P < .05). Joint angle differences varied in magnitude from 3.6° to 36.6° and joint center differences varied in magnitude from 0.4 to 2.4 cm. Differences were dependent upon the joint and anatomical plane/axis. Despite some observed limitations, markerless-based motion analysis may be a useful clinical research tool to evaluate thorax and upper-extremity kinematics during wheelchair mobility.