A lot of singers struggle to take and hold a long extended breath.
There are two reason to make the issue as follows.
People can control breaths precisely. Only when the diaphragm, internal and the external intercostal muscles and the costovertebral joint work very well.
So many people have problems with moving the costovertebral joint. If the costovertebral joint does not move widely, it cannot move the diaphragm, This is because of an increase to the space in the pleural cavity.
The posterior region of the thorax: The costovertebral joint connects the ribs to the thoracic vertebra.
(2) The hardness of vocal cords
The hard vocal cord muscles cannot follow the cricothyroid muscle when it is moving quickly, because the cricothyroid articulation cannot extend correctly.
If a person stops vibrating the vocal cord, precisely making only the vocal folds vibrate, the sound produced becomes a falsetto.
Only taking in and releasing short breaths will also cease or lessen controlling the pitch of the brief sounds being made, because it is impossible for mucosa tissue to move by itself.
It is not true that people sometimes say, “If you let out your voice all the time, your vocal cords will subconsciously move by thenselvese automatically.”
For anyone who truly wishes to make their vocal cord muscles flexible to a superior degree, I would like to recommend you look into and take ultrasonic therapy for the thyroid cartilage and stretch the cricothyroid articulation.
People who can extend the vocal cord, and possess superior flexibly, when vocalizing with a high-pitched voice can take in and release a very long breath in both high and low pitch sounds.