Aims and objectives
Ultrasound (US) has an important role in musculoskeletal (MSK) evaluation,
allowing the study of muscle morphology and function (1). US elastography can also offer semi-quantitative and/or quantitative assessment of tissue stiffness providing relevant information about adaptations of muscle mechanical properties (1,2). Supersonic Shear Image (SSI) is an US elastography method that offers a direct quantitative measure of tissue stiffness based on the velocity of shear waves (2).
Methods and materials
Sixteen young and active subjects,
(mean ± SD; height: 1.69 ± 0.07 m,
weight: 66.7 ± 8.1 kg,
age: 20.06 ± 2.02 years) participated in this study.
Data were collected in a single session.
All contractions were performed on an isokinetic dynamometer (Biodex System 3,
Biodex Medical Systems). After a warm-up,
participants performed a series of maximal contractions with the knee extensors,
followed by 2 sets of maximal Conc and Ecc contractions at diferent angular velocities and...
The results demonstrated an acute increase of around 10% in VL’s shear modulus as a result of performing maximal isometric,
and eccentric contractions.
The shear modulus of the VL also increased when the knee moved from 10º to 50º and then to 90º flexion.
a linear relationship between the shear modulus and the level of isometric muscle contraction was observed.
By employing SSI,
this study demonstrated that passive stiffness of the VL increases non-linearly with knee flexion as well as after maximal isometric and Ecc contractions,
with the acute effect of Conc contractions on VL’s passive stiffness being less clear.
A rather accurate relationship between the amount of isometric torque and VL’s stiffness was also demonstrated. SSI proved to be a good method to investigate muscle mechanical properties changes associated with muscle function.
(2015). Characterization of Shoulder Joint Morphology by Ultrasound .
National Ribat University. 2- Gennisson,
Viscoelastic and anisotropic mechanical properties of in vivo muscle tissue assessed by supersonic shear imaging.
Ultrasound in Medicine and Biology,
789–801. 3- Koo,
Quantifying the passive stretching response of human tibialis anterior muscle...