1.2.2 Breathing muscles
The work of antagonist muscle groups called inhalators and exhalators.
The main importance among all the inhalator muscles belongs to the diaphragm. It is the muscle unique in its shape, its muscle fibres, the method of fixation, the nature of its movements and its function.
Diaphragm is horizontal and makes the phrenic partition wall. In the relaxed state the diaphragm has a cupola like shape. When it contracts, its centre descends and the entire cupola flattens. This downward movement of the diaphragm reminds of the movement of a piston that draws air in during inhalation. In this case, the wall of the stomach protrudes forward; the chest expands and lifts up.
The phase of inhalation is marked by a small expansion of the nostrils, lowering of the trachea and larynx, and by opening of the glottis.
The abdominal muscles take the most important part in the process of inhalation. This is an outer pair oblique muscle, internal pair oblique muscle, the rectus muscle and the transverse abdominal muscle.
Quiet life breath in normal conditions (without doing physical exercises) is a passive act in its whole, and at exhalation phonation is an active phase.
Breathing cycle consists of three phases: inhale, exhale, and pause. The duration of inhalation and exhalation is about the same during quiet breathing. During exhalation, phase of phonation takes significantly longer than the inspiratory phase and can be arbitrarily detained.
Breath when phonation occurs faster when singing and a little slower when talking. Phonation breath can be done due to active contractions of the abdominal muscles, combined with a certain tone of the muscles of the pelvis and perineum.
Possibilities of voluntary regulation of amplitude, power, speed and rhythm of contractions of these muscles provide the foundation for developing the singing breath in trems with the requirements of vocal phrases and content of the musical text.