There is so much confusion out there in the voice world on what should be a very simple topic. The breathing needed for singing is not terribly difficult to explain physiologically, but it is crucial for singers to understand. Not only so that they can employ it correctly, but also so they guard themselves against misinformation that would have them doing it incorrectly. Proper breathing is vitally important to overcome the Valsalva maneuver which I have written about in a previous blog.
There are basically two sets of muscles used in proper breathing; the inspiratory muscles (that bring the air into the lungs) and the expiratory muscles (which help to expel the air from the lungs).
The inspiratory muscles are:
* The diaphragm
* External intercostals
The expiratory muscles are mainly the abdominals:
* external obliques,
* internal obliques,
* transversus abdominis and
* rectus abdominis
Basically, what should happen in proper breathing is the chest and the abdominal muscles should be relaxed. The singer should then take in a full breath without lifting the chest, but rather expanding the stomach, abdomen and ribcage. The singer must then keep this expansion going as they start to expire to sing the note or phrase, paying special attention so as not to hold their breath at all between inhalation and exhalation. If the breath is held at all the throat closes. Instead the throat should be held open at the initiation of the tone.
Upon inspiration it is crucial that neither the chest raise or the abdominal muscles contract. The lifting of the chest tends to bring in the setup for the Valvalva maneuver (constriction) while also canceling out some of the abdominal expansion. Additionally, the abdominal muscles are only muscles of expiration;i.e., they do not work upon inhalation. Therefore, any teacher or technique that claims a singer must tense the abdominal muscles for inhalation is teaching improper function. Any contraction of the abdominal muscles will cause the chest to have to raise and also blocks the diaphragm from being able to fully distend. The singer cannot take a full breath when this happens.
"During active expiration, the most important muscles are those of the abdominal wall (including the rectus abdominus, internal and external obliques, and transversus abdominus), which drive intra-abdominal pressure up when they contract, and thus push up the diaphragm, raising pleural pressure, which raises alveolar pressure, which in turn drives air out."
-John Hopkins School of Medicine
As you see from the quote above, the abdominal muscles compress the rib cage and push against the diaphragm to expel the air out. This is dangerous in singing for two reasons:
1) If the air is expelled out too aggressively, the vocal folds cannot resist it and are blown apart. This causes an aspirated, unclear sound which can cause damage to the vocal folds.
2) In order to stop the above from happening the singer is forced to resist the excessive expelling of air by locking the throat and constricting - which is the Valsalva Maneuver.
Therefore, ideally the inspiratory muscles should keep expanding so as to resist the expiratory muscles from taking over and expelling the air too quickly.
Another very important point that cannot be stressed enough is that the diaphragm has virtually no nerve endings. So it cannot really be felt enough to be controlled and it is active in every breath we take automatically. Put another way, if the proper breath is taken as explained above, the diaphragm will act automatically. Most singers and teachers mistakenly use the term "diaphragm" when they are really talking about the stretching of the abdominal muscles (not contraction) upon inhalation.
As you can see in the above video from the Stough Institute, upon inhalation the intercostals expand the rib cage - keep the chest relaxed without raising it - while the diaphragm drops down and flattens out. This causes the abdomen and sides to have to expand in order to make room. The abdominal muscles stay relaxed and stretch and expand. This expansion *must* continue throughout phonation.
"Always push out with the stomach and abdomen during the phrase, not in."
Additionally, I see many singers who have a bad tendency to use the sternomastoid muscles when breathing in. This happens especially in non-classical singing. You will notice many singers who have big, bulging muscles on the sides of their neck.
These muscles should absolutely not come into tension during inhalation. When the do come into tension they cause constriction. Many singers try to get the vocal folds to close by employing the sternomastoids and that can lead to constriction nodules. Instead, the sternomastoids should remain relaxed while the proper muscles of approximation close the vocal folds.