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).
In recent years,
this technique has become very popular for the study of muscle mechanics in vivo and...
Methods and materials
Sixteen young and active subjects,
ten males,
(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 performed through a ROM between 90°...
Results
The results demonstrated an acute increase of around 10% in VL’s shear modulus as a result of performing maximal isometric,
concentric,
and eccentric contractions.
The shear modulus of the VL also increased when the knee moved from 10º to 50º and then to 90º flexion.
Finally,
a linear relationship between the shear modulus and the level of isometric muscle contraction was observed.
Conclusion
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.
These results emphasise the value of an objective and quantifiable muscle US...
References
1- Salh,
A.
(2015).
Characterization of Shoulder Joint Morphology by Ultrasound.
National Ribat University.
2- Gennisson,
J.,
Deffieux,
T.,
Macé,
E.,
Montaldo,
G.,
Fink,
M.,
& Tanter,
M.
(2010).
Viscoelastic and anisotropic mechanical properties of in vivo muscle tissue assessed by supersonic shear imaging.
Ultrasound in Medicine and Biology,
36(5),
789–801.
3- Koo,
T.,
Guo,
J.,
Cohen,
J.,
& Parker,
K.
(2014).
Quantifying the passive stretching response of human tibialis anterior muscle using shear wave elastography.
Clinical Biomechanics (Bristol,
Avon),
29(1),
33–9.
4- Pedersen,
M.,...