Date of Award


Document Type

Scholarly Project

Degree Name

Master of Physical Therapy (MPT)


Physical Therapy

First Advisor

Susan H.N. Jeno


Abdominal Muscles -- physiology; Lung Volume Measurements; Voice


The purpose of this study was to determine if a relationship existed between electromyographical (EMG) activity in the abdominal muscles and the intensity of sound production. Currently, no consensus existsin the music profession regarding the appropriate use of the abdominal muscles during singing, even though it is known that the abdominal muscles playa significant role in sound production. As musicians strive to improve performance and therapists work to rehabilitate musicians and others who suffer from vocal deficits, understanding the basic muscular requirements of this activity/profession is essential to affect positive outcomes.

Eleven subjects with choral experience were recruited from the community. For each subject, pairs of carbon surface EMG electrodes were placed on the left side of the abdomen over the motor points of the rectus abdominis, internal oblique, and external oblique muscles and a ground electrode was placed over the iliac crest. The EMG signal was then compaired to a maximal voluntary contraction of the rectus abdominis, internal oblique, and external oblique muscles for normalization. Data collection consisted of two vocalization trials of six seconds each performed at each of three different intensities pianisimo, mezzo forte, and fortissimo. All singing trials were performed with the tone of G4, which was given using a chromatic pitch pipe. The subjects performed the tests while standing to ensure that stabilization of the thorax and abdomen was equal between trials.

The results of the study indicated that there was a significant increase in abdominal EMG activity during a six second singing trial between a pianissimo and forte intensity in the rectus abdominis, internal oblique, and external oblique muscles. Furthermore, when the data was analyzed, it was found that the external oblique contributed to a greater degree than the internal oblique muscle during a single vocal trial.

By using the information found in this study, physical therapists and other medical professionals dealing with patients who have vocal deficits should be better able to treat this group of patients. Therapists would be able to examine the recruitment of the abdominal muscles of these patients during vocalization. This may indicate a problem in the utilization of these muscles. Thus, it may be extrapolated that biofeedback training to teach proper recruitment or utilization of the abdominals should increase the patient's vocalization ability. A greater emphasis on abdominal control, training and increasing biomechanical balance may be indicated in vocalists and people with vocal deficits to help limit and prevent disability. However, there needs to be further studies to evaluate the effectiveness of these possible treatment strategies.