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EMG Measurement as a Function of Electrode Placement and Level of EMG

1980; Wiley; Volume: 17; Issue: 3 Linguagem: Inglês

10.1111/j.1469-8986.1980.tb00150.x

1469-8986

Donald A. Williamson, Leonard H. Epstein, Thomas W. Lombardo,

Motor Control and Adaptation

ABSTRACT Frontal EMG was concurrently measured using two different electrode placements for each of 12 subjects. One electrode placement was the standard placement of one electrode above each eyebrow (referred to as the horizontal placement). For the other placement, electrodes were positioned vertically above only the left eyebrow (referred to as the vertical placement). Comparisons between the measures of EMG using the two placements were assessed for three different levels of biofeedback‐influenced EMG activity. The horizontal and vertical EMG measures were found to be positively correlated both for the entire group and for individual subjects. Also, the two measures of EMG were positively correlated at three different levels of EMG, i.e., high, medium, and low. Comparisons of horizontal and vertical EMG indicated that horizontal EMG was consistently higher than vertical EMG at all levels of EMG. These findings suggest that placement of EMG electrodes is a very important variable in accurately measuring the magnitude of muscular electrical activity. However, if repeated measures of EMG are used to evaluate changes in muscle tension, and electrode placement is consistent across conditions, electrode placement is of only marginal importance.