title: Muscle shear elastic modulus is linearly related to muscle torque over the entire range of isometric contraction intensity.
abstract: Muscle shear elastic modulus is linearly related to muscle torque during low-level contractions (<60% of Maximal Voluntary Contraction, MVC). This measurement can therefore be used to estimate changes in individual muscle force. However, it is not known if this relationship remains valid for higher intensities. The aim of this study was to determine: (i) the relationship between muscle shear elastic modulus and muscle torque over the entire range of isometric contraction and (ii) the influence of the size of the region of interest (ROI) used to average the shear modulus value. Ten healthy males performed two incremental isometric little finger abductions. The joint torque produced by Abductor Digiti Minimi was considered as an index of muscle torque and elastic modulus. A high coefficient of determination (R(2)) (range: 0.86-0.98) indicated that the relationship between elastic modulus and torque can be accurately modeled by a linear regression over the entire range (0% to 100% of MVC). The changes in shear elastic modulus as a function of torque were highly repeatable. Lower R(2) values (0.89±0.13 for 1/16 of ROI) and significantly increased absolute errors were observed when the shear elastic modulus was averaged over smaller ROI, half, 1/4 and 1/16 of the full ROI) than the full ROI (mean size: 1.18±0.24cm(2)). It suggests that the ROI should be as large as possible for accurate measurement of muscle shear modulus.
authors.affiliation: EA 4334 "Motricité, Interactions, Performance", UFR STAPS, University of Nantes, Nantes, France. Electronic address: filiz.ates@boun.edu.tr.
authors.forename: Filiz
authors.initials: F
authors.lastname: Ateş
authors.affiliation: EA 4334 "Motricité, Interactions, Performance", UFR STAPS, University of Nantes, Nantes, France; The University of Queensland, NHMRC Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, Brisbane, Australia.
authors.forename: François
authors.initials: F
authors.lastname: Hug
authors.affiliation: EA 4334 "Motricité, Interactions, Performance", UFR STAPS, University of Nantes, Nantes, France.
authors.forename: Killian
authors.initials: K
authors.lastname: Bouillard
authors.affiliation: EA 4334 "Motricité, Interactions, Performance", UFR STAPS, University of Nantes, Nantes, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Jubeau
authors.affiliation: Supersonic Imagine, Aix en Provence, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Frappart
authors.affiliation: Supersonic Imagine, Aix en Provence, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Couade
authors.affiliation: Supersonic Imagine, Aix en Provence, France.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Bercoff
authors.affiliation: EA 4334 "Motricité, Interactions, Performance", UFR STAPS, University of Nantes, Nantes, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Nordez
mesh_terms: D000328:Adult; D055119:Elastic Modulus / Q000502:physiology*; D054459:Elasticity Imaging Techniques / Q000379:methods; D016552:Ergometry / Q000379:methods; D005385:Fingers / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D019415:Torque
keywords: Abductor Digiti Minimi; Force; Shear wave; Supersonic shear imaging; Ultrasound elastography