The main basis of the production of the singing voice is the Breath. If it is not adequate it compromises the rest of the vocal technique and in some extreme cases may lead to vocal pathology. Understanding where the speech therapist can intervene requires understanding the physiology of breathing.

In the singing voice it is important to breath in the most adequate and controlled way possible, because the exhalation air’s flow is the voice’s main source of energy.

The inhalation

In singing the main inhalation muscles are the diaphragm and external intercostals, which may have other muscles as accessory. Accessory inspiratory muscles will be recruited in addition to the major ones if there is a greater need of air volume.

In inhalation, due essentially to the involvement of the diaphragm and external intercostal muscles, the thorax moves around 3 levels: horizontal, frontal and sagittal. The horizontal level implies an external rotation movement of the ribs during inhalation and an internal rotation movement on exhalation. In the frontal level, there is a narrowing of the lower ribs on exhalation and spacing on inhalation. In the sagittal level there is an extension of the chest on inhalation and a flexion on exhalation. These movements in these three directions should occur more or less evidently because the increase of the chest volume during inhalation should follow the increase of the lung volume and vice versa. In inhalation, simultaneously with thorax movements, the diaphragm constricts leading to a downward movement of this muscle and consequently, the abdominal region expands anteriorly and laterally.

The exhalation

When the inhalation ends, the exhalation begins. The main muscles that participate in exhalation are the abdominal muscles as well as the external oblique, internal oblique and transversus abdominis, and the internal intercostal muscles. Other accessory muscles of the exhalation may participate. The rectus abdominis is also an expiratory muscle, but it participates only in the pressing or warning voice and, consequently, in the vocal effort.

At the beginning of exhalation, the external intercostal inspiratory muscles participate in this phase and contract to neutralize the retractable relaxation forces while maintaining the pulmonary pressure and expiratory flow required to initiate vocal fold vibration. Thus, the external intercostals help keep the position of the ribs apart (equal to the position of the end of inhalation) and delay the diaphragm’s retreat to its resting position, allowing the exhalation to be extended. In general this position lasts a short time and at this stage the expiratory muscles do not participate. There should be no tension to maintain the chest position at the end of inhalation, once it can be dangerous to the voice; usually a proper posture is required, but with a flexible torso.

As exhalation occurs, there is a progressive decrease in lung volume, inspiratory muscles gradually relax, and expiratory muscles begin to participate in it. In association with retractable strengths, abdominal muscles begin to be recruited to help decrease lung’s volume while maintaining expiratory flow constant. Briefly, they help controlling the speed of exhalation in phonation. At this stage a progressive and slow abdomen’s retraction is felt, with the participation of the external oblique, internal oblique and transversus abdominis muscles, while the progressive diaphragm’s retraction and a slow and progressive descent of the thorax occur. When the air is running out, the management of lung’s volume strengths also run out and the abdominal muscles contract, specifically the rectus abdominis, so as to maintain expiratory flow until the end of the singing vocalization reaching the vocal effort phase. Use this phase as little as possible. Exhalation ends and a new cycle begins.

Demystifying the myth “supporting with diaphragm”

In my work with singers I realize that there is generally this misconception that it is necessary to force air out of the lungs with contraction of the abdominal muscles, specifically the rectus abdominis, due to the idea of ​​“supporting with the diaphragm”. When the rectus abdominis comes into operation, what happens is a glottal constriction, that is, the joining of the vocal folds with tension, which usually occurs with a great effort, such as grabbing or pushing a heavy object, or while screaming, or during childbirth, which is not suitable for singing. When we contract the rectus abdominis muscle during singing we are compromising our vocal technique and damaging the vocal folds, being dangerous to vocal’s health. Therefore, it is important to note that the diaphragm only participates in inhalation, as described above. It is not possible to directly control this involuntary muscle to sing from it. It is the external oblique, internal oblique, and transversus abdominis muscles that control the speed of air’s exhalation, along with the internal intercostal muscles, during singing.

The speech therapist and the work with the singer

The speech therapist voice expert can help you optimize singing voice on many levels, one of them the process of breathing, because his/her academic education includes voice’s anatomy and physiology subjects as well as some vocal pedagogy subjects. Working with a speech therapist can be a complement to singing lessons, thus contributing to the singer’s health and vocal longevity.


Le Huche e Allali (data). La voix: anatomie et physiologie des organes de la voix et de la parole. 3ª édition. Paris (2001).

Michael, D. (2010). Dispelling Vocal Myths. Part 1: “Sing From Your Diaphragm!”. Journal of Singing, 66(5): 547-551.

Mendes, A., Ibrahim, S., Vaz, I. e Valente, T. (2018). EAVOCZ: Escala de Apreciação da Voz Cantada. Fundação Calouste Gulbenkian.

Guimarães, I. (2007). A Ciência e a Arte da Voz Humana Alcabideche: Escola Superior de Saúde do Alcoitão.

by Inês Silvestre

Instagram: @vocologista_inesilvestre
Speech therapist graduated at Escola Superior de Saúde do Alcoitão. Masters in Speech and Hearing Sciences at Escola Superior de Saúde da Universidade de Aveiro. Certification in Thérapie Manuelle Appliquée à l’Ortophonie – La Thérapie Manuelle au Service de la Mobilité, by Ósteovox. Certification in Estill Voice Training System – Level I & II. Professional experience in the field of voice since 2005, dedicated to the rehabilitation and optimization of the singing and spoken voice. Currently team member of the voice department at Sociedade Portuguesa de Terapia da Fala. Living and working in Coimbra at public hospital and private clinic.