Muscle activity in professional classical singing: a study on muscles in the shoulder, neck and trunk.

This study aimed to examine whether changes in the activity of shoulder and neck muscles have consequences for the activation of primary breathing muscles. It further aimed to compare muscle loading levels of professional and student singers. Four professional opera singers participated in the study. Previous unpublished recordings of 4 to 16 student singers and one opera singer were included to allow comparison of EMG loading levels between student and professional singers. Electromyographic (EMG) recordings of trapezius (TR), sternocleidomastoideus (STM), intercostals (INT), rectus abdominis (RC) and the lateral abdominal muscles (OBL) were performed. EMG biofeedback (BF) was performed on TR and STM to lower the activity in these two muscles and the potential change in EMG activity of INT, RC and OBL were examined. Three singing tasks were performed: aria, sustained tones and extreme tones. Each task was performed three times with variation in volume or pitch. Following the first performance of the singing tasks, the BF session was carried out and muscle activity recorded in a repeat performance of the same tasks. The EMG activity levels of all muscles were compared before and after BF. We found no significant effect of reduced TR/STM activity on the activation of INT, RC and OBL. Professional opera singers activated the TR, INT, RC and OBL muscles to higher levels than the student singers did. Another finding was large inter-subject variation in muscle usage, showing an idiosyncratic composition of the muscle contribution to subglottal pressure.