This article will first focus on those general features of the physiology and anatomy of the respiratory system that help in understanding how to breathe well, and then goes on to explain how the Alexander Technique deals with the issue of breathing.
First of all it's necessary to point out that breathing happens purely by using the respiratory muscles to change the volume of lungs, as many people seem to think that they can force air in and out by constricting the nasal passageway...
Inhalation is the more active phase of breathing. The main muscle used is the diaphragm. Tensing the diaphragm causes it to flatten, and this expands both lungs vertically. The external intercostal muscles also play a significant role in inhalation: they lift the ribs, thus expanding the lungs horizontally. When the need for oxygen increases, certain other muscles join in to further increase the expansion of lungs. Their role is to lift the sternum and upper ribs.
Exhalation doesn't normally require any effort. As the muscles used in inhalation relax, elasticity of the chest and lungs and surface tension inside lungs cause lung volume to decrease. When more forceful exhalation is needed, abdominal muscles and internal intercostals contract. Abdominal muscles force the diaphragm upwards and lower ribs downwards and internal intercostals pull the ribs downwards.
Lungs don't normally fill or empty completely as we breathe. The average total lung capacity is about six litres, whereas a typical inhalation at rest is only about half a litre. Even if we try to breathe as forcefully as we can, the volume of inhalation and exhalation will probably remain less than five litres, as there is no way to empty the lungs completely.
The Alexander Tecnique approach to breathing is indirect; Alexander Technigue does not advocate direct muscle control or systems like rib reserve breathing. Breathing changes when good primary control is established. By touching some areas of the upper back Alexander teachers often try to get their client to pay attention to the movement of posterior part of ribs. In particular this helps people who try to breathe by lifting and collapsing their sternum or even shoulders. The most obvious movement is the lateral rise and expansion of ribs, and simply being aware of this movement can stop people 'holding' their ribcage, i.e. the habitual muscle tension in the thoracic region lowers, and ribs can move more freely. Alexander tools like inhibition and directions, and in many cases also a little bit of subtle manipulation by the teacher, can be used to increase the mobility of the ribcage. A few deep inhalations and long exhalations tend to follow whenever progress is made.
Alexander teachers also try to encourage free movement of the diaphragm. Here problems tend to be of a more psychological nature; for many people vanity alone is a good enough reason to maintain a high degree of habitual muscle tone in the abdominal area. Also, it seems that voluntary control of the diaphragm is somehow linked to control of emotions or control of expression of emotions. Alexander Technique directions and becoming more aware of the role and movement of the diaphragm usually result in some release in this body region.
The 'Whispered Ah' is a useful tool when working with breathing, as it makes exhalation audible. Ideally a more smooth and continuous exhalation can be observed as a result of Alexander work. That exhalation may also have become longer: it is possible that Alexander Technique at least temporarily increases the length of the breathing cycle from the average five seconds (2 s. in, 3 s. out), although currently there is no research to back this up.