Non-invasive clinical measurement of the viscoelastic properties of tendon using acoustic wave transmission

Wearing, Scott C., Hooper, Sue L., Locke, Simon, & Smeathers, James E. (2013) Non-invasive clinical measurement of the viscoelastic properties of tendon using acoustic wave transmission. In Steinacker, Jürgen M. & Schleip, Robert (Eds.) Deutsche Zeitschrift für Sportmedizin, Sueddeutscher Verlag GmbH, Ulm, Germany, p. 148.

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Abstract

Background. In isotropic materials, the speed of acoustic wave propagation is governed by the bulk modulus and density. For tendon, which is a structural composite of fluid and collagen, however, there is some anisotropy requiring an adjustment for Poisson's ratio. This paper explores these relationships using data collected, in vivo, on human Achilles tendon and then compares estimates of elastic modulus and hysteresis against published values from in vitro mechanical tests. Methods. Measurements using conventional B-model ultrasound imaging, inverse dynamics and acoustic transmission techniques were used to determine dimensions, loading conditions and longitudinal speed of sound in the Achilles tendon during a series of isometric plantar flexion exercises against body weight. Upper and lower bounds for speed of sound versus tensile stress in the tendon were then modelled and estimates of the elastic modulus and hysteresis of the Achilles tendon derived. Results. Axial speed of sound varied between 1850 and 2090 ms-1 with a non-linear, asymptotic dependency on the level of tensile stress (5-35 MPa) in the tendon. Estimates derived for the elastic modulus of the Achilles tendon ranged between 1-2 GPa. Hysteresis derived from models of the stress-strain relationship, ranged from 3-11%. Discussion. Estimates of elastic modulus agree closely with those previously reported from direct measurements obtained via mechanical tensile tests on major weight bearing tendons in vitro [1,2]. Hysteresis derived from models of the stress-strain relationship is consistent with direct measures from various mamalian tendon (7-10%) but is lower than previous estimates in human tendon (17-26%) [3]. This non-invasive method would appear suitable for monitoring changes in tendon properties during dynamic sporting activities.

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ID Code: 65425
Item Type: Conference Paper
Refereed: Yes
Additional Information: Bindegewebe in der Sportmedizin - 1. Ulmer Symposium CONNECT 2013
Additional URLs:
ISSN: 0344-5925
Divisions: Current > Schools > School of Clinical Sciences
Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Current > Schools > School of Exercise & Nutrition Sciences
Copyright Owner: Copyright 2013 Please consult the authors
Deposited On: 03 Jan 2014 04:03
Last Modified: 14 Jan 2014 04:39

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