Exploration of the center of mass kinematics correlation with established gait measures in post-spinal cord injury.

Introduction: Walking mobility is important for health and quality-of-life after spinal cord injury (SCI). Outcome metrics monitoring rehabilitation progress typically focus on gait speed, assistive technologies, and muscle strength, but do not address all gait determinants in a single metric which limits understanding of gait deviations and compensatory strategies. Center of mass (CoM) is a global parameter reflecting whole-body movement and motor control. We hypothesized CoM kinematics might quantitatively differentiate between clinically accepted ambulatory categories and correlate with clinical gait performance metrics. Methods: We collected CoM and six established clinical gait assessments from five ambulatory individuals with incomplete SCI over four sessions. Single-sine coefficients of a Fourier Series model were optimized via a non-linear gradient-based optimizer to compute CoM symmetry indices in the mediolateral, anteroposterior, and inferiosuperior directions. We computed correlations between the indices and clinical assessments with a Spearman Correlation Analysis ( Results: CoM differentiated across impairment levels and uniquely captured deviations from neurotypical gait. Symmetry indices strongly or moderately correlated with 10-Meter Walking Test, 2-min Walking Test, Lower Extremity Motor Score and SCI-Functional Ambulation Inventory depending on the CoM direction Conclusions: CoM appears to reflect the multidimensionality of gait and clarify some of the deficiencies of clinically accepted measures. These findings suggest CoM analysis is clinically relevant, and supports further exploration of symmetry indices as figures of merit for gait performance and informing rehabilitation interventions post-SCI.