The effect of sustained and rhythmic contractions on the electromyogram (EMG).

Abstract

AbstractLarsson. L. E., H. Lidnderholm, and T. Kingqvist. The effect of sustained and rhythmic contractions on the electromyogram (EMG). Acta physiol. scand. 1965. 65. 310–318.—The effect on the EMG of various types of muscular work was studied in 20 healthy volunteers. The work consisted of 1) cycling of rnasirnal intensity on a bicycle ergometer. 2) exhausting sustained contractions of the elbow flexors. 3) internlittent rhythmic contractions of the same muscles as in 2 of a duration. the sum of which was equal to the duration of the sustained contractions. Particularly after the sustained muscular contractions, and to a less degree after rhythmic contractions or cycling, there appeared in the active muscles after exercise an increased number of polyphasic action potentials. The change was reversible. The duration of all action potentials decreased after exercise. There was no significant change in amplitude. The genesis of the EMG changm arc discussed particularly with regard to the circulatory conditions and metabolism of the muscle in the various types of muscle contractions.