A Comparative Biomechanical Analysis the Vertical Jump between Flatfoot and Normal Foot

Abstract

Flatfoot has been one of the most common foot deformity, which gives rise to several malfunctions or disoders to the foot and lower extremity. Difference between flatfoot and normal foot mainly present in the middle foot, while few is known about the biomechanical difference under barefoot vertical jump. The objective of this study is to investigate the difference of flatfoot and normal foot while vertical jumping under barefoot condition. Twenty males (ten with flatfoot and ten with normal foot) volunteered to participate in this study. Foot morphology was measured with Easy-Foot-Scan. Foot kinetics and joint kinematics were obtained from EMED force platform and Vicon motion analysis system. Results showed that flatfoot group had a significantly larger peak pressure in the region of hallux and larger contact area of center forefoot than that of normal foot group, and larger contact area in medial midfoot. The flatfoot group presented larger plantarflexion and smaller external rotation to the ankle, and larger flexion and abduction and smaller external rotation to the knee than normal foot group during vertical jump. It can be concluded that people with flat-arched feet may have a poorer ability of self-regulation when facing a movement with rapid impact force like vertical jump, which will increase the risk of injuries. This information will be valuable for future work in structure, function and potential treatment of low arched feet.