Ivanova, Z. D.; Ivanov, T. B.; Raikova, R. T.

In the present work, we propose a new integrated mathematical model for the neuromuscular activation of a motor unit, describing the four consecutive processes, leading to muscle contraction--neural impulse propagation, acetylcholine transport in the neuromuscular junction, calcium release in the muscle cell, and force generation. We connect in an appropriate way models of the respective processes, known from the literature, and validate the resulting model by showing that it can reproduce with high accuracy experimental data for two motor unit twitches on a rat medial gastrocnemius muscle and can numerically restore the sequence of events that result in force generation. Sensitivity analysis for some of the model parameters is further performed to study their effect on the model solutions and to show that they can be related to known malfunctions or treatments of the neuromuscular system.