The potential influence of the heel counter on internal stress during static standing: A combined finite element and positional MRI investigation

Hdl Handle:
http://hdl.handle.net/10149/58276
Title:
The potential influence of the heel counter on internal stress during static standing: A combined finite element and positional MRI investigation
Authors:
Spears, I. R. (Iain); Miller-Young, J. E. (Janice); Sharma, J. (Jagannath); Ker, R. F. (Robert); Smith, F. W. (Francis)
Affiliation:
University of Teesside. Sport and Exercise Subject Group; Mount Royal College. Department of Math, Physics and Engineering. Canada; Infantry Training Centre (ITC). Catterick Garrison; The University of Leeds. Institute of Integrative and Comparative Biology; University of Aberdeen. Department of Radiology.
Citation:
Spears, I. R. et al. (2007) 'The potential influence of the heel counter on internal stress during static standing: A combined finite element and positional MRI investigation', Journal of Biomechanics, 40 (12), pp.2774-2780.
Publisher:
Elsevier
Journal:
Journal of Biomechanics
Issue Date:
2007
URI:
http://hdl.handle.net/10149/58276
DOI:
10.1016/j.jbiomech.2007.01.004
Abstract:
Confinement of the heel due to the counter of the shoe is believed to influence heel pad biomechanics. Using a two-dimensional finite element model of the heel pad and shoe during a simulation of static standing, the aim of this study was to quantify the potential effect of confinement on internal heel pad stress. Non-weightbearing MRI and weightbearing MRI with plantar pressure and ground reaction force data were recorded for a single subject. The non-weightbearing MRI was used to create two FE models of the heel pad, using either homogeneous or composite material properties. The composite model included a distinction in material properties between fat pad and skin. Vertical and medial-lateral forces, as measured on the subject's heel, were applied to the models and vertical compressive strains for both models were comparable with those observed by weightbearing MRI. However, only for the composite model was the predicted plantar pressure distribution comparable with measured data. The composite model was therefore used in further analyses. In this composite model, the internal stresses were located mainly in the skin and were predominantly tensile in nature, whereas the stress state in the fat pad approached hydrostatic conditions. A representation of a running shoe, including an insole, midsole and heel counter was then added to the composite heel pad to form the shod model. In order to investigate the counter effect, the load was applied to the shod model with and without the heel counter. The effect of the counter on peak stress was to elevate compression (0-50%), reduce tension (22-34%) and reduce shear (22-28%) in the skin. In addition, the counter reduced both compressive (20-40%) and shear (58-80%) stress in the fat pad and tension in the fat pad remained negligible. Taken together the results indicate that a well-fitted counter works in sympathy with the internal structure of the heel pad and could be an effective reducer of heel pad stress. However, further research needs to be undertaken to assess the long-term effects on the soft-tissues, practicalities of achieving good fit and behavior under dynamic events.
Type:
Article
Keywords:
barefoot; footwear; plantar pressure; shod; soft tissues; heel; stress; MRI; static standing; confinement
ISSN:
0021-9290
Rights:
Author can archive post-print (ie final draft post-refereeing). For full details see http://www.sherpa.ac.uk/romeo/ [Accessed 14/01/2010]
Citation Count:
0 [Web of Science and Scopus, 14/01/2010]

Full metadata record

DC FieldValue Language
dc.contributor.authorSpears, I. R. (Iain)-
dc.contributor.authorMiller-Young, J. E. (Janice)-
dc.contributor.authorSharma, J. (Jagannath)-
dc.contributor.authorKer, R. F. (Robert)-
dc.contributor.authorSmith, F. W. (Francis)-
dc.date.accessioned2009-04-01T10:47:47Z-
dc.date.available2009-04-01T10:47:47Z-
dc.date.issued2007-
dc.identifier.citationJournal of Biomechanics; 40 (12): 2774-2780-
dc.identifier.issn0021-9290-
dc.identifier.doi10.1016/j.jbiomech.2007.01.004-
dc.identifier.urihttp://hdl.handle.net/10149/58276-
dc.description.abstractConfinement of the heel due to the counter of the shoe is believed to influence heel pad biomechanics. Using a two-dimensional finite element model of the heel pad and shoe during a simulation of static standing, the aim of this study was to quantify the potential effect of confinement on internal heel pad stress. Non-weightbearing MRI and weightbearing MRI with plantar pressure and ground reaction force data were recorded for a single subject. The non-weightbearing MRI was used to create two FE models of the heel pad, using either homogeneous or composite material properties. The composite model included a distinction in material properties between fat pad and skin. Vertical and medial-lateral forces, as measured on the subject's heel, were applied to the models and vertical compressive strains for both models were comparable with those observed by weightbearing MRI. However, only for the composite model was the predicted plantar pressure distribution comparable with measured data. The composite model was therefore used in further analyses. In this composite model, the internal stresses were located mainly in the skin and were predominantly tensile in nature, whereas the stress state in the fat pad approached hydrostatic conditions. A representation of a running shoe, including an insole, midsole and heel counter was then added to the composite heel pad to form the shod model. In order to investigate the counter effect, the load was applied to the shod model with and without the heel counter. The effect of the counter on peak stress was to elevate compression (0-50%), reduce tension (22-34%) and reduce shear (22-28%) in the skin. In addition, the counter reduced both compressive (20-40%) and shear (58-80%) stress in the fat pad and tension in the fat pad remained negligible. Taken together the results indicate that a well-fitted counter works in sympathy with the internal structure of the heel pad and could be an effective reducer of heel pad stress. However, further research needs to be undertaken to assess the long-term effects on the soft-tissues, practicalities of achieving good fit and behavior under dynamic events.-
dc.publisherElsevier-
dc.rightsAuthor can archive post-print (ie final draft post-refereeing). For full details see http://www.sherpa.ac.uk/romeo/ [Accessed 14/01/2010]-
dc.subjectbarefoot-
dc.subjectfootwear-
dc.subjectplantar pressure-
dc.subjectshod-
dc.subjectsoft tissues-
dc.subjectheel-
dc.subjectstress-
dc.subjectMRI-
dc.subjectstatic standing-
dc.subjectconfinement-
dc.titleThe potential influence of the heel counter on internal stress during static standing: A combined finite element and positional MRI investigation-
dc.typeArticle-
dc.contributor.departmentUniversity of Teesside. Sport and Exercise Subject Group; Mount Royal College. Department of Math, Physics and Engineering. Canada; Infantry Training Centre (ITC). Catterick Garrison; The University of Leeds. Institute of Integrative and Comparative Biology; University of Aberdeen. Department of Radiology.-
dc.identifier.journalJournal of Biomechanics-
ref.assessmentRAE 2008-
ref.citationcount0 [Web of Science and Scopus, 14/01/2010]-
or.citation.harvardSpears, I. R. et al. (2007) 'The potential influence of the heel counter on internal stress during static standing: A combined finite element and positional MRI investigation', Journal of Biomechanics, 40 (12), pp.2774-2780.-
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