Recruitment Visco-elasticity of the Tendon
The biomechanical properties of the tendon as well as other soft tissues are characterized by non-linear viscoelasticity (VE), and irreversible adaptation to loading (preconditioning). Our study focuses on the tendon non-linear viscoelasticity. To date, no viscoelastic model for tendons was found to be valid under general loading protocol. A new theory of the tendon Recruitment Viscoelasticity (RVE) will be presented: it is a stochastic model based on the observed gradual recruitment with stretch of the originally crimped collagen fibers, and assumes that each of the fibers bears load only when straight and stretched, and then it exhibits a linear viscoelastic response.
The new RVE theory was experimentally tested against measured response of the tendon under stress relaxation, creep and quick release protocols. The results exhibit good fit, thus supporting the validity of the new micro-structural based RVE model.