It is common for voice instructors to describe the source of vocal sound—the larynx—as a delicate organ, and easily injured by misuse or overuse. But, the laryngeal musculature, like that of the pharynx and oral cavity, is naturally durable and resistant to fatigue. It makes little sense then to concentrate on how to avoid vocal overuse; instead, our focus should be on how to maximize the considerable power and performance potential that is inherent in our voice muscles. This, of course, takes us into the realm of exercise.
All exercise programs devoted to increasing muscular strength utilize the target-based, overloading strategy. Exercise programs are usually designed in accordance with a person’s individual needs. If you want to increase the strength of your chest musculature—the pectoralis major—for instance, this goal is best achieved by tailoring a muscle overloading exercise program that is specific to that muscle group, like bench-pressing. It is important to connect the right kind of exercise to the type of muscles that are being exercised and overloaded.
A remarkable quality of the vocal musculature is that various muscles and muscle groups work antagonistically with respect to one another during voice production. For example, although pitch change is a very easy task to achieve, it presupposes a muscular tug-of-war between the muscles that elongate the vocal folds—the crico-thyroid muscles—and those that shorten them—the thyro-arytenoid/vocalis muscles (which are located in the vocal folds themselves). The final balance that is established in this muscular struggle is the pitch that you sing.
The musculature of the larynx, pharynx, oral cavity, and soft palate, like those of the eyes, is mostly rapidly-adjusting (fast-twitch) endurance muscles. Their capacity for high levels of precise movements, over long periods of time, is also astonishing. Even an average singer is able to modulate, with precision and reflex-like action, his vocal musculature to increase or decrease vocal power, alter pitch, and create a good variety of vocal sounds—and to do so with remarkable endurance.