Comparison of the Loading Rate and Lower Limb Angles on Drop-landing between a Normal Foot and Flatfoot

[Purpose] The purpose of this study was to analyze lower limb angles and the loading rate during the drop-landing motion of a normal foot and flatfoot and ultimately to offer basic data for flatfoot exercise therapy. [Subjects] For this study, 18 adults from Cheonan with no musculoskeletal lesions were collected as a sample. The sample was divided into normal foot (n=9) and flatfoot (n=9) groups. Each group performed a drop-landing motion on a force plate with markers attached to the anterior superior iliac spine, the greater trochanter of the hip, the lateral epicondyle of the knee, the lateral malleolus, and the fifth metatarsal head. The motion was measured in 3D. The data for the angle of the hip joint, knee joint, and ankle joint during the drop-landing motion and the loading rate and maximum vertical reaction force at the force plate were measured. [Results] There were significant differences in the maximum vertical reaction force and loading rate during the drop-landing motion between the normal foot and flatfoot. There was a significant difference in the right ankle joint in terms of the variation in the lower limb angles. [Conclusion] It was difficult for the flatfoot to disperse the loading rate during the drop-landing motion, and it showed an increase in the lower limb bending angle. It was considered that proper pose control for the absorption of loads and strengthening of the lower limb were definitely needed for a flatfoot.