Diploma thesis – the Biological feedback in therapy deals with electromyography (EMG), investigative techniques based on electromyography, myofeedback applications and intention controlled myofeedback (IMF therapy). Electromyography is described on principal and there are used electrodes presented. In investigative methods are mentioned their basic progress at investigation by the help of elektromyography. Next are present artifacts, which in the elektromyography signal values. For myofeedback I worked up basic study. Myofeedback is based principle in IMF therapy. The effect of IMF therapy was verified with synchronized signal electroencephalograph (EEG) and EMG. In concrete I worked with movement-related cortical potentials (MRCP) components and Bereitschaftspotential (BP). BP presents highlight component from MRCP and alone BP precluding fulfillment movement. It was tested on metering, that BP occur before executed movement. Idea IMF therapy is correct.