Mathematical modeling and simulation of the postural control loop--Part II.

The engineering analysis and modeling of the neuromuscular system is an exciting and challenging area of research where we may learn something about the principles of controlling large, complex systems. This review is limited to the most peripheral subsystem: the postural control loop. In the first part, we reviewed the input-output properties of the motoneuron pool, modeling of the motor unit action potential and analysis of the interference electromyographic activity. Also included were the engineering techniques to quantitatively study electromyographic activity and its relationship to muscle force. The second part of this review focuses on the biomechanical models of the muscle based on Hill's work as well as the modern sliding filament theory. This section will also include models of the proprioceptive receptors: the muscle spindle organ and the Golgi tendon organ. In the final paper we will discuss various models and simulations of the peripheral loop and their applications to study physiological system behavior such as tremor.