It is muscular action that regulates the velocity, and quantity of breath. By muscular power the vocal ligaments are brought together; the larynx is raised or depressed; the pharynx expands or contracts ; the soft palate and uvula rise and fall; the mouth enlarges or diminishes; the lips assume their various positions; and the tongue performs its numberless, and most delicate movements. Seeing, then, that voice culture is based on muscular action, and that the muscles which govern the vocal organs do not, in any way, differ from those situated in other parts of the body; it is of paramount importance, that the laws of nature, on which muscular education is superstructed, should be thoroughly understood; for to ignorance, or neglect of these, do most of the ills, that singers and orators suffer, owe their existence.
It is a law in nature, —
(1) That the muscular system becomes feeble if seldom excited to action.
(2) That within certain limits, muscles increase in size, strength, and aptitude, in proportion to the use made of them.
(3) That the rapidity, and easy succession of movements is promoted by their judicious repetition; for the more frequently the fibres are thrown into action, the easier does their action become.
(4) That excess of muscular activity is always followed by exhaustion, and the movement of the same muscle, when too frequently repeated, becomes difficult, and, if persevered in, the organ at last becomes incapable of action.
(5) That exertion, and rest, are equally necessary for the increase, and maintenance of muscular power.
Barraclough, Arthur. “Observations on the physical education of the vocal organs.” (1876).