A-24 Development of Foot Musculoskeletal Model for Shoe Designing

Abstract

In a designing process of functional footwear, it is necessary to well-understand biomechanics of the foot/ankle complex. The purpose of this study is to develop 3-dimensional foot/shank musculoskeletal simulation model which can predict foot deformation and foot-shank interaction behavior under various loading conditions. Foot/shank model include knee joint was developed by using SIMM (Software for Interactive Musculoskeletal Modeling, ver. 7.0, MusculoGraphics Inc.). In the model, lower extremity was defined as 15 segments and 14 joints based on multi-body dynamics. Talocrural joint, Subtalar joint, Transverse-tarsal joint, Tarsometatarsal joints, and Metatarsophalangeal joints were considered anatomical rotation axes, and they were constrained by 15 ligament models represented as non-linear elastic ligament element. As a result, it is confirmed that the developed model provided good agreement with foot joints behaviors in the previous studies, and foot-shank interaction behavior via Subtalar joint (e.g. tibial internal-rotation caused by subtalar-pronation) could be simulated. Furthermore, the model clarified influences of foot ligaments on rigidity of medial longitudinal arch. It is expected that the developed model provide useful insights to design footwear considered foot-shank joint mechanics.