In this article, we present the design of a smart electrostimulator for muscle rehabilitation or reinforcement, using fast computations, in order to control the muscular force. The Ding and al. model allows to predict and to optimize the muscular force response to functional electrical stimulation. [1]. We analyze the estimation of the Ding and al. parameters using an approximation of the force response [6] which depends upon the 6 parameters of the Ding's model and we derive optimization scheme which bypass the time computational expensive integration of the dynamics of the Ding and al. equations.