PURPOSE This study analyzed the relationship between the center of pressure (CoP) trajectory area and ankle inversion/eversion movement across different walking speeds and established a new assessment method for predicting ankle instability. METHODS Twenty-seven healthy young adult males (20 yrs) performed treadmill walking trials at three speeds (slow, normal, and fast). Their cumulative CoP trajectory area and ankle inversion/eversion angles were analyzed, with particular focus on the third quadrant area (3QA). RESULTS During slow walking, mediolateral CoP range (p < .05) and 3QA (p < .05) increased significantly compared to normal and fast walking. Concurrently, ankle inversion/eversion angle (p < .05) and range of motion (p < .05) also increased. Furthermore, 3QA exhibited significant negative correlations with maximum ankle eversion angle (p = .001) and eversion angular velocity (p = .005). CONCLUSIONS This study provides findings that the CoP trajectory’s cumulative area, specifically 3QA, serves as a critical predictor of ankle joint eversion kinematics. These findings have potential implications for ankle instability assessment, prevention, footwear design, and rehabilitation protocols.
