PASSIVE ELASTIC CHARACTERISTICS AND MUSCULOSKELETAL KINEMATICS OF HUMAN FOOT FOR BIOMECHANICAL ANALYSIS

In this study we investigated the relationship between kinematic and kinetic characteristics of foot joints resisting ground reaction force (GRF). Passive elastic characteristics of joint were obtained from the experiment using three cameras and one force plate. With the mathematical models that relates joint angle and plantar pressure, we could get the kinematic data of the joints which are not available from conventional motion analysis. During the calculation process we used approximate equations and partial plantar pressures. The maximum angular displacements of each tarsometatarsal joint ranged from 4 to 7 and the maximum moments were from 200N⋅cm to 1500N⋅cm. Foot kinematic data calculated from the approximated equations, which were represented by the correlation between moment and angular displacement, and the data from motion analysis were very similar. We found that the movements of foot joints were decided by the passive characteristics of the joints when ground reaction force acts.