Towards a footwear design tool: Influence of shoe midsole properties and ground stiffness on the impact force during running

Abstract

Several spring-damper-mass models of the human body have been developed in order to reproduce the measured ground vertical reaction forces during human running (McMahon and Cheng, 1990; Ferris et al., 1999; Liu and Nigg, 2000). In particular, Liu and Nigg introduced at the lower level of their model, i.e. at the interface between the human body and the ground, a nonlinear element representing simultaneously the shoe midsoles and the ground flexibility. The ground reaction force is modelled as the force supported by this nonlinear element, whose parameters are identified from several sets of experimental data. This approach proved to be robust and quite accurate. However, it does not explicitly take into account the shoe and the ground properties. It turns out to be impossible to study the influence of shoe materials on the impact force, for instance for footwear design purposes. In this paper, a modification of the Liu and Nigg's model is suggested, where the original nonlinear element is replaced with a bi-layered spring-damper-mass model: the first layer represents the shoe midsole and the second layer is associated with the ground. Ground is modelled as an infinite elastic half-space. We have assumed a viscoelastic behaviour of the shoe material, so the damping of shoe material is taken into account. A methodology for the shoe-soles characterization is proposed and used together with the proposed model. A parametric study is then conducted and the influence of the shoe properties on the impact force is quantified. Moreover, it is shown that impact forces are strongly affected by the ground stiffness, which should therefore be considered as an essential parameter in the footwear design.

Joint loading decreased by inexpensive and minimalist footwear in elderly women with knee osteoarthritis during stair descent

“…The increased rigidity of the soles of the heeled shoes (36) and not the heel elevation could be responsible for the higher KAM observed while descending steps compared to the Moleca and barefoot conditions. This sole rigidity, primarily during the weight acceptance and propulsion phases, may increase the ground reaction force magnitude, and consequently the KAM peaks.…”

A general relationship links gait mechanics and running ground reaction forces

“…The multi-mass models, in contrast, were formulated to evaluate the potential influence of numerous factors on the waveform rising edge. Many of the features incorporated into the multi-mass models provide reasonable theoretical representations of the numerous, potentially influential musculoskeletal complexities present (Liu and Nigg, 2000;Ly et al, 2010;Nigg and Liu, 1999;Nikooyan and Zadpoor, 2011;Zadpoor and Nikooyan, 2010). These include mass components that vary in stiffness, that are both rigid and wobbling in nature, and that are connected with both serial and parallel elements (Fig.…”

“…Most current versions include 14 or more input variables derived via forward dynamics simulations (Chi and Schmitt, 2005;Liu and Nigg, 2000;Ly et al, 2010;Nigg and Liu, 1999;Nikooyan and Zadpoor, 2011;Zadpoor and Nikooyan, 2010). Per their intended purpose, these models are able to provide close, post facto fits to the rising edge of the force-time waveforms that result from rear-foot strike mechanics at jogging speeds under a variety of surface, footwear and other conditions (Ly et al, 2010;Zadpoor and Nikooyan, 2010). However, these models do not attempt to predict the falling edge of the waveform, they do not explain the differently shaped waveforms that typically result from fore-foot strike mechanics, and their ability to fit waveforms from intermediate and fast running speeds is completely unknown.…”

Foot speed, foot-strike and footwear:linking gait mechanics and running ground reaction forces

“…At present, several factors are known to introduce the shape variation that occurs predominantly in the initial portion of these force-time waveforms. These include: running speed (Bobbert et al, 1991;Kuitunen et al, 2002;Munro et al, 1987;Weyand et al, 2009;Weyand et al, 2010), the portion of the foot that initially contacts the running surface (Cavanagh, 1987;Chi and Schmitt, 2005;Dickinson et al, 1985;Ker et al, 1989;Lieberman et al, 2010;Nigg et al, 1987) and footwear (Liu and Nigg, 2000;Ly et al, 2010;Nigg et al, 1987;Nigg and Liu, 1999;Zadpoor and Nikooyan, 2010). Current understanding rests heavily on the two types of models most frequently used to interpret these waveforms: the spring-mass model and multi-mass models.…”