We used a high-definition camera (EOS 200D II, Canon) to record the joint trajectory. In the experiment, we placed the camera on the left side of the subjects and collected the video at a rate of 60 fps/s. In order to obtain plantar pressure, we used a flexible film pressure sensor (MD30-60, Leanstar, Suzhou, China) with a range of 10kg, thickness < 0.6mm, response point < 200g, response time < 1ms, and measurement diameter of 23mm. Flexible film pressure sensor is a kind of resistance sensor. The output resistance decreases with the increase of the pressure applied to the surface of the sensor. The pressure can be measured by a specific pressure-resistance relationship. In order to ensure the accuracy of the data, pressure sensors were set on the soles and heels of the subjects.