Kinematic validation of an IMU-based 2-segment foot model using optical motion capture and the oxford foot model

Abstract In recent years, Inertial Measurement Units (IMUs) have emerged as a promising alternative to Optical Motion Capture (OMC) systems. However, many applications simplify biomechanical models, particularly for the foot and ankle, by representing them as a single rigid segment. To address this limitation, a 2-segment Foot Model was developed and validated against the Oxford Foot Model using OMC. Twelve participants were equipped with both systems, and their kinematics were measured during overground walking. The data were compared using statistical parametric mapping (SPM), Pearson correlation, and range of motion (ROM) analysis. The results revealed significant differences in some aspects of the curves according to SPM, but the overall shape demonstrated very high correlation values. Additionally, ROM was not significantly different in six out of nine cases. These findings indicate that, while absolute values were not identical, the IMU-based system provides a valid representation of foot and ankle kinematics when analyzed as two distinct segments.