title: Muscle shear modulus measured with ultrasound shear-wave elastography across a wide range of contraction intensity.
abstract: BACKGROUND
  In this study we examine the repeatability of measuring muscle shear modulus using ultrasound shear-wave elastography between trials and between days, and the association between shear modulus and contraction intensity over a wide range of intensities.
  
  
  METHODS
  Shear modulus of the biceps brachii was determined using ultrasound shear-wave elastography during static elbow flexion (up to 60% of maximal contraction) in healthy young adults.
  
  
  RESULTS
  The correspondence of shear modulus was confirmed in phantoms between the manufacturer-calibrated values and the shear-wave elastography values. The intraclass correlation coefficient of muscle shear modulus was high: 0.978 between trials and 0.948 between days. Shear modulus increased linearly with elbow flexion torque across contraction intensity, and its slope was associated negatively with muscle strength.
  
  
  CONCLUSIONS
  Muscle shear modulus measured with ultrasound shear-wave elastography may be useful for inferring muscle stiffness across a wide range of contraction intensity. In addition, it has high repeatability between trials and between days.
authors.affiliation: Department of Sports and Life Sciences, National Institute of Fitness and Sports in Kanoya, Kanoya, Kagoshima, Japan.
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Yoshitake
authors.forename: Yohei
authors.initials: Y
authors.lastname: Takai
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kanehisa
authors.forename: Minoru
authors.initials: M
authors.lastname: Shinohara
mesh_terms: D002138:Calibration; D054459:Elasticity Imaging Techniques / Q000379:methods*; D004550:Elbow / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging* / Q000502:physiology*; D019047:Phantoms, Imaging; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D033081:Shear Strength; D055815:Young Adult
keywords: biceps brachii; elastography; electromyography; muscle stiffness; muscle tone