2.4. Instruments

During the testing process, a total of 38 optical markers with a diameter of 14 mm were used. These markers were attached to the anatomical locations of the participants based on the Gait2392 muscle-skeletal model, and the same operator consistently placed the markers. The movement trajectories of the markers were recorded using an eight-camera Vicon motion capture system (Vicon Metrics Ltd., Oxford, UK) at a sampling frequency of 1000 frames per second [35,36]. Ground reaction forces and COP measurements were obtained using an embedded Kistler force platform (Kistler Force Platform System 92-81B, Winterthur, Switzerland) fixed in the center of the floor, with a sampling frequency of 200 Hz [37]. Before each experiment, the cameras and laboratory setup were calibrated to ensure stable marker trajectories and minimize noise interference. All participants were instructed to wear standardized tight shorts and were barefoot during the testing process.