An alpha motoneuron pool model to analyse EMG measured reflex output

The intrinsic properties of the human soleus alpha motoneuron pool and the surface EMG are modelled. The model consists of an alpha motoneuron pool model generating the firing patterns of motor units in a human soleus muscle and a muscle model simulating the soleus surface EMG. The model is able to give a quantitative prediction of the motoneuron pool activity and the reflex EMG output at different excitation levels. The simulated data are consistent with experimentally obtained results. The simulations show that the reflex strength is highly dependent on the intrinsic threshold properties of the alpha motoneuron pool during static isometric muscle contractions.