Psychosomatic Medicine 5:132-138 (1943)
© 1943 American Psychosomatic Society

The Relation Between Electromyographic Measurements and Subjective Reports of Muscular Relaxation

¹ Department of Diseases of the Nervous System of the Harvard Medical School, and the Psychiatric Department of the Massachusetts General Hospital, Boston, Massachusetts

Electromyogram tracings of the flexor and extensor muscles were made on a series of 37 patients with psychiatric and neurological diseases and on 10 normal control subjects while closing and opening the fist at the rate of one fist, every one, two and three seconds.

The greatest relaxation values were obtained by measurement of the tracing when the time interval between the discrete movements was three seconds.

One-half of the subjects reported that they felt relaxed in their arms and fingers in response to a questionnaire. All of the control subjects were in this group.

A correlation (biserial) of .69 was found between the average relaxation values of flexors and extensors of the forearm and answers to the questions dealing with muscular relaxation in the arms and fingers.

Biserial correlations of .58 and .54 and .64 were found between the relaxation values of the extensors, the flexors, the lowest relaxation values for either flexors or extensors and the answers to the same questions.

Distribution curves of the results showed that the selectivity of the test was greater for subjects reporting muscular relaxation than for those reporting muscular tension.