**10. Conclusion**

Computational Intelligence in Electromyography Analysis – 404 A Perspective on Current Applications and Future Challenges

lower the value of this filter, the smoother the curve will be [27, 28].

**Figure 9.** A) original signal interference. B) rectified original signal [3].

The signals collected in real time in the original format are stored in files. After this phase certain mathematical processes are applied. The purpose of this processing is to make correction, i.e., to transform negative signals into positive signals. This is necessary to allow averaging of the analyzed signal, since if such correction is not performed, the average of the signals will be near zero. This is because the negative and positive are symmetrical. In the post-rectification, a 5 Hz low-pass filter can be run in order to have a signal wrap. The

*9.1.7. Filtering of the rectified signal* 

For dynamic sampling, active electrodes (with preamps) are less susceptible to artifacts or ambient noise, which can be observed when comparing them with signals collected during isometric contractions in volunteers with dysfunctions.

EMG signals are affected by the anatomical and physiological properties of muscles, the peripheral nervous system and the instrumentation used to collect the signal. Thus it is important to understand basic muscle functions to correctly record EMG signals [12].

It can be said that signal processing begins, indirectly, as soon as the electrodes are placed. Electrode placement involves several factors that are decisive for the level and purity of the EMG signal to be collected, including: cleaning the skin, the amount and temperature of the conductive gel, the position of the electrodes and the signal-to-noise ratio, which expresses the balance between the energy of the signal generated during muscle contraction and the energy of noise from various undesirable sources [27].

Therefore, sEMG can be recommended as a tool for analyzing and interpreting electrical signals emanated during muscular contractions in both normal and pathological situations and can be applied in the study of motor function and functional rehabilitation [4].
