I. Introduction
The aim of the study project is the design of a smart electrostimulator, in the isometric case (without displacement of the muscle), for muscle rehabilitation or reinforcement based, in particular, on modern sensors and fast computations using embedded electronics. The idea is to design training programs to track a force of reference [4] or to maximize the muscular force. Each training program can be converted into an optimization problem. The mathematical equations presented below are the tools to the design of this smart electrostimulator.