Analysis of Pelvis and Lower Limb Coordination in Stroke Patients Using Smartphone-based Motion Capture.

Understanding the coordination between the pelvis and lower limbs in individuals with hemiplegic gait is crucial for deciphering their walking patterns. While studies have focused on lower limb kinematics in stroke patients, research on pelvis-lower limb coordination remains limited. This study aims to assess pelvis-lower limb coordination and kinematics in stroke patients using statistical parametric mapping (SPM) and smartphonebased markerless motion capture. Seventeen stroke patients and twenty healthy individuals were recruited to collect locomotion data using dual smartphone videos. For comparison, the time-series coordination of the pelvis-thigh, thigh-shank, and shank-foot among the control, paretic, and nonparetic limbs were analyzed using SPM and continuous relative phase (CRP). The results showed that there were significant differences (p < 0.05) in the CRP curves of the pelvis-thigh in the sagittal plane (50 - 62% of the gait cycle), pelvis-thigh in the coronal plane (0 - 100% of the gait cycle), thigh-shank (65 - 92% of the gait cycle), and shank-foot (13 - 29% and 57 - 68% of the gait cycle) across the different segments. Assessing the coordination and kinematics of the pelvis and lower limbs using a feasible and portable motion capture technique could assist clinicians in identifying potential muscle dysfunction while uncovering the compensatory strategies that individuals with hemiplegic gait may use to maintain balance, stability, and propulsion during walking. These results could guide clinicians in targeting interventions to reduce spasticity and strengthen muscles, ultimately enhancing coordination, optimizing gait mechanics, and improving functional outcomes.