Abstract
EMG activities of sternocreidomastoid and trapezius muscles during the isometric maximum voluntary exercises of the head, neck, shoulder, back and mandible were studied in 10 healthy examinees.
These results obtained were as follows:
1. In the sternocreidomastoid muscle, the mean of integrated EMG values showed its maximum on the exercise of the head in which one rotated his mentum contralaterally-rostally forward; in the nuchal and shoulder regions of the trapezius muscle, on the exercise in which one raised his shoulder rostally; and in its back region, on the exercise in which one pulled his shoulder backward.
2. In average, the rates of integrated EMG value on the mandibular exercises to the maximal value on the head, neck, shoulder and back exercises were 9.2 and 19.6% in the superior and inferior regions of the sternocreidomastoid muscle, and 15.4, 1.1 and 8.4% in the nuchal, shoulder and back regions of the trapezius muscle, respectively.
3. These results were discussed in relation to unpleasant sensations on the neck, shoulder and back regions in occlusal diseases.
