Force-deformation properties of the human heel pad during barefoot walking

Wearing, Scott C., Hooper, Sue L., Dubois, Philip, Smeathers, James E., & Dietze, Albrecht (2014) Force-deformation properties of the human heel pad during barefoot walking. Medicine and Science in Sports and Exercise, 46(8), pp. 1588-1594.

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Abstract

Introduction: The plantar heel pad is a specialized fibroadipose tissue that attenuates and, in part, dissipates the impact energy associated with heel strike. Although near maximal deformation of the heel pad has been shown during running, in vivo measurement of the deformation and structural properties of the heel pad during walking remains largely unexplored. This study employed a fluoroscope, synchronized with a pressure platform, to obtain force–deformation data for the heel pad during walking.

Methods: Dynamic lateral foot radiographs were acquired from 6 male and 10 female adults (age, 45 ± 10 yrs; height, 1.66 ± 0.10 m; and weight, 80.7 ± 10.8 kg), while walking barefoot at preferred speeds. The inferior aspect of the calcaneus was digitized and the sagittal thickness and deformation of the heel pad relative to the support surface calculated. Simultaneous measurement of the peak force beneath the heel was used to estimate the principal structural properties of the heel pad.

Results: Transient loading profiles associated with walking induced rapidly changing deformation rates in the heel pad and resulted in irregular load–deformation curves. The initial stiffness (32 ± 11 N.mm-1) of the heel pad was an order of magnitude lower than its final stiffness (212 ± 125 N.mm-1) and on average, only 1.0 J of energy was dissipated by the heel pad with each step during walking. Peak deformation (10.3 mm) approached that predicted for the limit of pain tolerance (10.7 mm).

Conclusion: These findings suggest the heel pad operates close to its pain threshold even at speeds encountered during barefoot walking and provides insight as to why barefoot runners may adopt ‘forefoot’ strike patterns that minimize heel loading.

Impact and interest:

2 citations in Scopus
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2 citations in Web of Science®

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ID Code: 78117
Item Type: Journal Article
Refereed: Yes
Keywords: Biomechanics, Adipose Tissue, Elasticity, Foot
DOI: 10.1249/MSS.0000000000000281
ISSN: 0195-9131
Subjects: Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000)
Divisions: Current > Schools > School of Clinical Sciences
Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Copyright Owner: Copyright 2014 American College of Sports Medicine
Copyright Statement: This is a non-final version of an article published in final form in Medicine & Science in Sports & Exercise:
August 2014 - Volume 46 - Issue 8 - p 1588–1594
doi: 10.1249/MSS.0000000000000281
Deposited On: 05 Nov 2014 22:59
Last Modified: 09 Sep 2015 04:15

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