Abstract
Static stretching is widely used to provide muscle hypotonicity, which is caused by change in muscle tissue structure, intended to prevent musculoskeletal disabilities. However, quantitative evaluation of hypotonicity during stretching was very difficult because traditional measurements confuse mechanical stress relaxation. To resolve this problem, we propose a new evaluation method for hypotonicity based on muscle viscoelastic properties using fractional calculus model that is known to be effective for biomaterials. In this study, we investigated viscoelasticity indexes given by continuous muscle reaction force during static stretching. From the indentation test for stretching of rectus femoris muscle, we confirm that those indexes decreased significantly between early phase and final phase of the stretching. The results suggest that our method is useful for quantitative evaluation of muscle hypotonicity during stretching.
