The inability of non-invasive techniques to estimate muscle damage limits our understanding of injury occurrence.
Shear wave elastography (SWE) technique provides a reliable (Lacourpaille et al. 2012) and accurate (Eby et al. 2013) quantification of individual muscle shear modulus (i.e., stiffness). This method is relevant for clinical settings as the measurement can be performed at rest, and the acquisition and data processing are fast. Our French partners showed that muscle shear modulus increases in the early instants after damaging exercise (Lacourpaille et al. 2014b; Guilhem, […], Lacourpaille, et al. 2016). They hypothesized that this finding could originate from the perturbation of calcium homeostasis (Whitehead et al. 2001). In that case, the increase in passive muscle shear modulus after a damaging exercise would be closely related to the number of myofibrillar disruptions and membrane damage resulting in intracellular calcium overload.
Accurate quantification of muscle damage requires histological examination of muscle biopsy samples by determining the number of myofibrillar disruptions. This invasive procedure is unlikely to be routinely used in sport settings and clinical practice. Our group has a long-lasting experience with the study of musculoskeletal function and adaptation, both at the macroscopic and cellular levels. In relation to damage, Raastad and colleagues (2010) showed a strong relationship between strength loss after exercise and the number of fibers with myofibrillar disruptions. Strength is in this respect a good indicator of muscle damage but it is too unspecific to validate the suitability of SWE as a non-invasive tool to detect muscle damage, or to address the mechanistic hypotheses above.
This project is aimed at investigating the links between measurements of changes in muscle shear elastic modulus and at the sub-cellular level. Here we seek funding for mobility exchanges between partners, to implement the SWE methodology.