The Diaphragm
“The nuisance value in playing there would be two. One is the diaphragm, and the other is the tongue. I hardly ever even considered the embouchure. The embouchure is easily worked with and easily controlled. But the tongue and the diaphragm, these two become problems. And it does take a little special work.”
Jacobs is the pioneer of modern-day knowledge of respiration in relation to wind instruments. His research was conducted through thousands of hours of independent research studying the normals and abnormals of respiration. Several doctors, most notable Dr. Bruce Douglass and Dr. Benjamin Burrows, worked with Jacobs. Many have said that Jacobs knows more about the mechanics of respiration than many physicians, although he is primarily self-taught. There is truth in this because physicians are more concerned with diseases and not as concerned with the physiology of respiration as is Jacobs. Jacobs realizes his limitations, and if he senses a medical problem with a student, he always recommends that a physician be consulted immediately.
From Arnold Jacobs: Song and Wind*
The diaphragm is a muscular partition between the thoracic and the abdominal cavities. Its location, in the front, is at the base of the sternum [breastbone] and in the back on the spine and at the base of the rib cage. During contraction, the diaphragm descends, the chest cavity is enlarged and air pressure is lowered. This is responsible for 75 percent of the normal volume increase of the lungs. It is a physical impossibility to use the diaphragm to raise intrathoracic pressure. For deeper breathing the ribs are elevated and expanded outwards, further expanding the chest by the external intercostal muscles. Small increments in volume can be obtained by further elevation of the ribs by muscles of the neck and back.
Because the diaphragm can only move up and down, Jacobs commonly makes the analogy of the diaphragm to an old-fashioned insect sprayer. “With the bug sprayer, if you pull the handle out, the pressure decreases. If you push it in, the pressure increases—the diaphragm is like a piston.” There are no nerves in the diaphragm to tell the brain what position it is in. The diaphragm has only pain sensing nerves.
Many teachers use the phrase, “blow from the diaphragm,” and use the term “diaphragmatic support.” “The term ‘support’ raises questions in itself. Many people make the mistake of assuming that muscle contraction is what provides support. The blowing of the breath should be the support, not tension in the muscles of the body, but the movement of air that is required by the embouchure or reed.
“Support is always a reduction phenomenon. Wherever the player is going to build pressure, according to Boyle’s Law, he is going to have a reduced chamber. The chamber can be reduced anywhere it is previously enlarged. It gets bigger when you take air in. It gets smaller when you move air out. When you blow, the brain will deactivate the diaphragm, normally. If you are using air to create pelvic pressures, the diaphragm will not deactivate—it will remain stimulated. Abdominal muscles that would normally be expiratory will start contracting, and there will be a closure at the throat or the tongue or the lips, which causes the air pressure to bear down on a downward-contracting diaphragm to increase the pelvic pressure for expulsion of fecal matter. Of course, to bypass this we have to have a blowing phenomenon that is different,” Jacobs says.
The ability of the diaphragm to move is directly related to the position of the body. The respiratory system should not be thought of as a single bellows, but as a series of segmented bellows. “If I lean to the right, the use of the right lung is diminished. By leaning to the left, the use of the left lung is diminished. By leaning backwards, the upper lung motion is diminished. By leaning forwards, the diaphragmatic activity is diminished [as less air can be taken in]. “Exhalation begins with the relaxation of the inspiratory muscles. During normal breathing, exhalation is passive. In forced exhalation, such as playing a wind instrument, the relaxed diaphragm is lifted by contraction of the abdominal muscles [neural inhibition] and the chest is drawn downwards and in by the internal intercostal muscles. Breathing out can be inhibited by either contraction of the diaphragm [the paradox or perversity of “diaphragmatic support”], or by obstruction of an outflow at the larynx. Both these “brakes” are used during normal respiration and especially during straining maneuvers.
Emptying the lungs in a normal person may take only four seconds. Eighty percent of the air should be dischargeable within one second and the remainder in the next two or three seconds. By pulling in the lower abdomen, the diaphragm is forced up and a bit is forced out—something Jacobs does not recommend. The best advice is to take in a full breath. Jacobs says, “There is no reason not to take a full breath—it’s free, it costs nothing.”
*Arnold Jacobs: Song and Wind, Copyright 1996 Windsong Press, Ltd., All rights reserved.