Stability analysis of nonlinear muscle dynamics using contraction theory

Biological motor control systems have a distributed, rather than centralized, architecture. Instabilities in movement, such as tremor, can in part arise from the interactions between different physiological feedback mechanisms. Contraction theory provides tools for analyzing the stability of nonlinear distributed control systems. Here we use contraction theory to investigate the stability provided by the mechanical feedback of muscle dynamics, finding that these dynamics are exponentially stable. This theoretical result complements previous computational and experimental findings regarding the efficacy of viscoelastic properties of muscle in compensating for disturbances