Foot Model for Investigating Foot Biomechanics and Footwear Design - Computational Biomechanics of the Musculoskeletal System - page 3

1 Foot Model for Investigating

Foot Biomechanics
and Footwear Design

Ming Zhang, Jia Yu, Yan Cong, Yan Wang,
and Jason Tak-Man Cheung

ContentS
Summary ............................................................................................................................................ 3
1.1 Introduction .............................................................................................................................. 4
1.2 Development of a Comprehensive Foot Model......................................................................... 7
1.2.1 Geometric Model of Human Foot and Support ............................................................ 7
1.2.2 Material Properties ....................................................................................................... 9
1.2.3 Loading and Boundary Conditions ............................................................................ 11
1.2.4 Model Validation ........................................................................................................ 12
1.3 Applications of the Finite Element Model .............................................................................. 13
1.3.1 Effect of Soft Tissue Stiffening .................................................................................. 13
1.3.2 Effect of Insole Design ............................................................................................... 14
Acknowledgments ............................................................................................................................ 16
References ........................................................................................................................................ 16

Summary
Information on load transfer of foot internal structures as well as the foot-support interface
during various activities is useful in enhancing biomechanical knowledge for foot support design.
Modeling of the human foot and ankle is challenging because of the very complex structures.
Computational models can be used to understand joint biomechanics and design proper foot
supports. Three-dimensional geometrically accurate finite element (FE) models of the human foot-
ankle structures were developed from reconstructed magnetic resonance (MR) images. The foot FE
model consists of 28 separate bones, 72 ligaments, and the plantar fascia, embedded in a volume
of encapsulated soft tissue. The main bone interactions were simulated as contacting deformable
bodies. The analyses took into consideration the nonlinearities of material properties, large
deformations, and interfacial slip/friction conditions. A series of experiments on human subjects
and cadavers were conducted to validate the model measurements. These experiments recorded
plantar pressure distribution, foot arch and joint motion, and plantar fascia strain under different
simulated weight-bearing and orthotic conditions of the foot. The validated models can be used for
parametric studies to investigate the biomechanical effects of tissue stiffness, and orthotic perfor-
mances on the foot-ankle complex.

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