Mechanical properties of the shoe sole material affect the loading of the musculo-skeletal system during locomotion. The visco-elastic characteristics of the shoe sole material influence the shock attenuation properties of footwear during the heel strike during running and walking. To investigate the effect of impact loading during the heel strike, the sole of the shoe can be modelled as a mechanical system represented by a nonlinear spring and damper.
The purpose of the mathematical modelling of the heelless shoe is to relate the visco-elastic behaviour of the sole material determined by the stiffness and damping characteristics to the biomechanical parameters like the ground reaction force applied to the body during a heel strike. The parameters for the mathematical model corresponding to a heelless shoe can then be compared with a conventional running shoe with a view of investigating to what extend the heelless design can attenuate the shock during a heel strike. Also it provides a standard way of changing the material properties with a view of decreasing the ground reaction force during the heel strike.
To standardise the ground reaction force and deformation measurements of the shoe the first study will focus on testing the different marker placement set ups and ground reaction force and pressure measurements. This includes synched measurement of force and the sole deformation using a synchronised and simultaneous motion capture, force and pressure measurement. Furthermore the kinematic data gathered from the Vicon system is going to be translated to the deformation of the different regions of the sole. It takes into account the thickness of the sole and the three dimensional rotation of the shoe during contact period with the ground.
Using this information the force–deformation graph during the loading and unloading will be reconstructed and evaluated for the different running velocities. This is then compared with the force-deformation graphs gathered from testing the shoe in a mechanical testing machine, to relate the biomechanical characteristics of the shoe, to the mechanical and material properties of the sole material. Also a protocol will be developed to find the regional ground reaction force based on the pressure profile. Additionally the anterio-posterior force may also be used to model the propulsive characteristics of the shoe.
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