ABSTRACT

EA values result as an amplitude measure from many uncontrollable influences (varying distances between the two active electrodes, the kind of electrode gel and the time needed for it to take effect, the impedance of the amplifier, the thickness of the subcutaneous skin layer over a muscle, etc.). The amplitude measures of the electromyographic data are therefore not directly interpretable. They vary greatly in repeat measurements under identical conditions even with the same test subject and even more when the measurements result from different tests after the electrodes have been reapplied even under the same operating conditions. Intermuscular comparisons are also not possible using electromyographic activity. Therefore a standardization of the EA values is necessary.