抄録
A mathematical model is formulated for activated muscles under stretching. "Yielding", which is characterized as the decrease in the rate of muscle force during stretching, is reported in the literature for activated cat soleus muscles. We hypothesize that such "yielding" mainly results from the change of an active state that is determined by step functions of activation stimulus which reflects the properties of muscle conditions. The activation stimulus increases when the muscle begins to be stretched, and it decreases after a short duration at the start of stretching and when the stretching is stopped. The effect of velocity and stimulation rate is expressed by determining the change of activation stimulus systematically. The simulation results show that the "yielding" is described by a simple frame of the model. The model might be applied to simulate the behavior of activated muscles during stretching such as walking and sports.
