Would ancient Greece have ever trained her manhood to the most perfect state of physical culture, if Nature’s laws had been so little understood, and master and pupil had worked contrary to each other? The perfection they reached in cultivating the entire muscular system, should be emulated by the singer, in training those groups of muscles which govern the vocal organs; for the muscles of the chest and throat are in no wise different to those occupying other parts of the body: they are all subject to the same laws. And as the Greeks reduced all their knowledge of physical culture to a perfect system, so must the singer do. They thoroughly understood that the least transgression of Nature’s laws invariably brought its own punishment with it; and they also knew, that the thorough observance of them permitted the muscles to be exercised in such a manner, as to produce the most harmonious development of all parts concerned, and enabled them to perform with the greatest facility, and carry out in the best form possible, all movements required.

Barraclough, Arthur. Observations on the physical education of the vocal organs. Vol. 2. 1876.