Electrode Size

'Electrode size' is defined as the size of the conductive area of a SEMG electrode. According to literature the size of SEMG electrodes used in (clinical) practice varies from 1mm2 to a few cm2. The size of SEMG electrodes influences the recorded SEMG.
Upon an increase of the size perpendicular to the muscle fibres (bar electrodes perpendicular to the muscle fibres), it is expected that the view of the electrodes increases. No quantitative data on the extend of this effect on the SEMG characteristics is available at the moment.

Upon an increase of the size in the direction of the muscle fibres, it can be shown that this has an integrative effect on the SEMG signal, increasing the detected amplitude and decreasing the high frequency contents.
The European inventory showed that the circular electrodes with a diameter of 10 mm are preferred most. For bipolar sensors, in general, the size of electrodes should be large enough to be able to record a reasonable pool of motor units, but small enough to avoid crosstalk from other muscles. For daily use it will be practical to have only one type of electrode of the same size for all SEMG recordings.

SENIAM recommendations for electrode size

The SENIAM recommendations for sensors restrict to bipolar sensors only. 'Electrode size' is defined as the size of the surface of the conductive area of a SEMG electrode.

SENIAM recommends that the size of the electrodes in the direction of the muscle fibers is max. 10mm.