Influence of inter-electrode distance on EMG

This paper reports experimental research undertaken to study the effect of variation of inter-electrode distance on the electromyogram (EMG). The experiments were conducted on ten healthy subjects and they performed isometric contraction of their biceps of the right arm at 20, 50 and 80% of their maximal voluntary contraction (MVC). EMG was recorded using surface electrodes with the distance between the two active electrodes being 18 and 36mm. It has been observed that at low levels of muscle contraction there was no significant variation due to the change in the distance between the electrodes while at 50 and 80% of MVC there was a significant change in the amplitude of the EMG. Using time-frequency analysis of EMG, the study demonstrates a variation of the spectral content of the EMG with change in the IED. The study also has shown that there is a variation of the EMG with muscle contraction but that the comparison should be done if the distance between the electrodes has been kept constant.