In vitro Demonstration of Shear Strain Distribution of the Human Gastrocnemius-Soleus Aponeurosis during Submaximal Isometric Contraction using Velocity-encoded Phase Contrast MRI
Shin D, Ahn S, Sinha S, Lee H, Hodgson J, Edgerton R, Finni T
University of California
It has been postulated in muscle physiology literature that aponeurosis structures are made up of thin adjacent layers. We have developed phase contrast MRI based techniques to monitor tissue displacements with sufficiently high resolution. We use it to demonstrate in vivo in the human lower leg, that during isometric contraction, (i) the gastrocnemius (GM) moves to a different extent than the soleus on the other side of the aponeurosis, (ii) along the length of the SOL-GM aponeurosis, the displacements of these muscle groups are spatially heterogenous, and (iii) across the aponeurosis, a spatial shear strain distribution is generated.