Dynamic Foot Model for Impact Investigation - Computational Biomechanics of the Musculoskeletal System - page 61

5 Dynamic Foot Model for

Impact Investigation

Jia Yu, Duo Wai-Chi Wong, and Ming Zhang

ContentS
Summary .......................................................................................................................................... 61
5.1 Introduction ............................................................................................................................ 61
5.1.1 Experimental Approach .............................................................................................. 62
5.1.1.1 Pendulum Impact Experiments .................................................................... 62
5.1.1.2 Accelerometer Measurement ....................................................................... 62
5.1.1.3 Material Test ................................................................................................ 62
5.1.2 Computational Approach ............................................................................................ 63
5.2 Implicit Dynamic Method ......................................................................................................64
5.2.1 Solution Procedures ....................................................................................................64
5.3 Dynamic Finite Element Model for Plantar Heel Pain during Heel Strike ............................. 65
5.3.1 Finite Element Model Development ........................................................................... 65
5.3.2 Experimental Validation ............................................................................................. 66
5.3.3 Results ......................................................................................................................... 67
Acknowledgments ............................................................................................................................ 69
References ........................................................................................................................................ 69

Summary
The foot acts as a shock absorber upon contact with the ground. Repetitive impact on the foot is
considered one of the main etiological agents in foot pain and problems. Footwear or foot support
designed for shock absorption has been identified as one of the important strategies for prevention
of foot/ankle injuries. Simulations of foot impact are necessary for a better understanding of foot
support design. This chapter reviews experimental and computational methods of existing investi-
gations on foot impact and introduces implicit dynamic finite element (FE) methods. As an example
of potential applications of such an implicit dynamic model for prevention of heel pain, results of
the dynamic FE foot model during heel strike are presented.

5.1 IntroduCtIon
The foot is a shock absorber for the entire body during locomotion. Many methods are employed to
assess the dynamic characteristics of the foot and ankle, such as clinical assessment, gait analysis,
cadaveric examination, and dynamic computational analysis.
Repetitive impact forces during walking, running, and jumping impose substantial loading on
the foot. The ground reaction force may reach up to three times the body weight during walking
(Nigg, Cole, and Bruggemann 1995; Whittle 1999; Chi and Schmitt 2005) and about ten times dur-
ing jumping (Cavanagh and Lafortune 1980; McClay et al. 1994). This repetitive impact force is
considered one of the main etiological agents in degenerative joint diseases and acute injuries of the
musculoskeletal system (Collins and Whittle 1989; Jorgensen 1985).

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