Virtual tools allow us to simulate surface electromyography signals (EMGs) in a pandemic period. In this study we propose the simulation of EMG signals and the design of a system for the acquisition, conditioning and visualization of muscle signals that can be used in muscle rehabilitation sessions. We perform an extraction of characteristics of an EMG signal, in the domain of time and frequency in relaxation events and voluntary contraction of a muscle. The relaxation and contraction signals were simulated using 21 harmonics (11 for the contraction state and 10 for the relaxation state). Then the signal was conditioned with operational amplifiers to be presented through a graphical interface by the Labview program, where the user will be able to see three (3) important components, amplitude and frequency parameter settings, EMGs graph and relaxation light indicators, a non-powerful contraction and muscle contraction.