Center of Foot Pressure and Free Moment Changes During Gait in Adolescents With Right and Left Scoliosis

Background and Aims Adolescent idiopathic scoliosis (AIS) is a multifactorial spinal deformity with high prevalence, affecting spinal alignment, postural control, and gait mechanics. This study aims to examine the effect of scoliosis curvature direction on center of pressure (COP) kinematics and free moment (FM) parameters during gait. Methods In this study, participants included 14 adolescents with AIS categorized into right scoliosis (n=7) and left scoliosis (n=7), and 16 healthy peers as controls. Data related to the COP and FM parameters were collected using two Kistler force plates during the stance phase of gait. Statistical analysis was done using MANOVA for discrete variables and statistical parametric mapping (SPM) for time-series data. Results The AIS group had significantly higher body height (P=0.021) and trunk length (P=0.052) than the control group. No significant differences were found in the COP and FM parameters for the right leg between the groups. However, the left scoliosis subgroup showed a significantly larger range of anteroposterior COP displacement in the left leg (convex side) compared to the control group (P=0.027), as well as a larger FM mean and impulse compared to the right scoliosis subgroup (P=0.019). Conclusion Adolescents with right and left scoliosis demonstrate different gait adaptations, particularly in COP and FM dynamics, highlighting the need for curvature direction-specific rehabilitation protocols to enhance gait stability and neuromuscular control in AIS. Future studies should analyze scoliosis directions separately to characterize their biomechanical profiles.