Disclosed herein is modeling system and method of a muscle activation that is both biophysically-plausible and practically-robust over a wide range of physiological input conditions such as excitation frequency and muscle length. The modeling system comprises: a first module transforming electrical signals from motoneurons to concentration of Ca2+ in the sarcoplasm; a second module receiving the concentration of Ca2+ from the first module and transforming the concentration of Ca2+ to and activation dynamics of muscle; and a third module receiving the activation dynamics of muscle from the second module and transforming the activation dynamics of muscle to muscle force. The first module and the second module compensate a length dependency of the concentration of Ca2+ and the activation dynamics.