Microstructural mechanism of skeletal muscle injury and a new constitutive model of skeletal muscle

This paper concerns with the prediction of mechanical behavior and damage of skeletal muscle. To clarify the mechanism of muscle injury, we conducted biomechanical and pathological evaluations for muscle contusion and strain injury. The results showed correlations between severity of pathological damage and functional disability on contraction. The results also suggested that microscopic damage of muscle fibers, peripheral circulation or motor units has significant effects on the change of macroscopic function. Thus we also performed tensile tests for the microstructure of skeletal muscle and found mechanical properties of muscle fascicle were independent of strain-rate and muscle activation. Based on these experimental evaluations, we developed a new constitutive model of skeletal muscle taking into account viscoelasticity, anisotropy of deformation and damage evolution.