Soft tissues (skin, cornea, tendon...) play an important role in the architecture of the human body. In particular, they provide a support function linked to their mechanical properties. These can change depending on the environment, but also with age or pathologies. Soft tissues are essentially made up of a network of collagen fibers (and sometimes elastin), surrounded by a matrix of proteins rich in water. In the end, there are only a few cells. Still, it is these cells which induce the mechanical modifications of the tissue, by reorganizing the network of fibers which surrounds them in reaction to the mechanical movements of this same network. Thus, it seems important to be able to predict how macroscopic mechanical loadings are transmitted at the microscopic scale, and vice versa.

Using a new experimental approach to observe microstructure during mechanical loadings, we were able to show that classical models do not correctly predict the fiber network movements, which led us to construct a new interpretation of the physical origin of fiber motions.