Heel--shoe interactions and the durability of EVA foam running-shoe midsoles

Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT, UK.
Journal of Biomechanics (Impact Factor: 2.5). 10/2004; 37(9):1379-86. DOI: 10.1016/j.jbiomech.2003.12.022
Source: PubMed

ABSTRACT A finite element analysis (FEA) was made of the stress distribution in the heelpad and a running shoe midsole, using heelpad properties deduced from published force-deflection data, and measured foam properties. The heelpad has a lower initial shear modulus than the foam (100 vs. 1050 kPa), but a higher bulk modulus. The heelpad is more non-linear, with a higher Ogden strain energy function exponent than the foam (30 vs. 4). Measurements of plantar pressure distribution in running shoes confirmed the FEA. The peak plantar pressure increased on average by 100% after 500 km run. Scanning electron microscopy shows that structural damage (wrinkling of faces and some holes) occurred in the foam after 750 km run. Fatigue of the foam reduces heelstrike cushioning, and is a possible cause of running injuries.

Download full-text


Available from: Raquel Verdejo, Jun 23, 2015
1 Follower
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The rapid spread of various sports games has changed the role of shoes from the simple protection of human feet to more advanced ones like competency improvement. Accordingly, intensive research efforts are being focused on the development of high-competency sports shoes by taking kinesiology and biomechanics into consideration. However, the success of this goal depends definitely on the reliable evaluation of the main functions required for sports shoes. As the first part of our study on the landing impact analysis of court sports shoes, this paper introduces a coupled foot-shoe finite element model in order to fully reflect the mutual interaction between the foot and the shoe, not relying on traditional independent field experiments any more. Through illustrative numerical experiments, we assess the reliability of the proposed coupled FEM model by comparing with the experimental results and investigating the fundamental landing impact characteristics of sports shoes.
    Journal of Mechanical Science and Technology 12/2014; 23(10):2583-2591. DOI:10.1007/s12206-009-0801-x · 0.70 Impact Factor
  • Source
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Although running is associated with many health benefits, it also exposes the body to greater risk of injury. Foot orthoses are an effective strategy to prevent such injuries. Comfort is an essential element in orthosis design since any discomfort alters the runner's biomechanics, compromising performance and increasing the risk of injury. The present study analyses the perceived comfort of three types of orthoses: custom-made, prefabricated and original running shoe insoles. Nine comfort variables for each insole were assessed in a sample of 40 runners. Custom-made and prefabricated insoles were both perceived as significantly more comfortable than the original insoles. The differences were clinically relevant and were potentially causes of modifications in running gait. Although the prefabricated insoles were rated slightly higher than the custom-made insoles, the differences were not statistically significant. This study shows that prefabricated insoles constitute a reasonable alternative to custom-made insoles in terms of comfort.
    Ergonomics 07/2014; 57(10):1-7. DOI:10.1080/00140139.2014.938129 · 1.61 Impact Factor