Determination of the longitudinal arch moment of the human foot complex during gait: (Inverse dynamics model analysis)

"Arch moment" of human foot complex is determined by model analysis using Newton Euler inverse dynamics argorism. Human foot is arch shaped structure that is highly complex, composed of 28 bones, any ligaments and intrinsic/extrinsic musculotendons support. The arch displacement occurs during a gait cycle. This motion has an instant center, which is placed on the navicular bone, as we have decided using X-ray analysis. The foot model is constructed by two rigid bodies connected with one hinge joint. The arch moment determination materials are (1) kinetic and kinematic data, (2) body segment parameters. Each floor reaction force to forefoot and hindfoot are measured by two force plates. Three adult subjects were studied during normal gait. The anthropometric data are acquired by 12-camera VICON system. The body segment parameters are estimation data using piaster model. We discuss that the arch moment is equal to the arch support moment composed of ligaments and muscles, and the ligaments constraint the foot arch like a rope.