Thoughts on expanding one’s lung capacity –
I believe Terry is thinking of vital capacity, or the volume of air released by a forced exhalation (expiration) after a maximal inspiration [am I right?]
Increasing vital capacity for playing a wind instrument can be achieved by two means: increasing the volume of inspired air, and improving (controlling) expiration. For better inspiration, it is possible to increase the volume of the chest cavity, since the ribs do move – they’re pivoted in the back at the vertebrae and at the front by the sternum and the costal cartilages. Getting them to move more can be helped by exercising the muscles of inspiration, both the diaphragm and the accessory muscles in the chest and neck. Greater diaphragm contraction force will probably do the major part of this, and, yes, it does push the abdominal contents down and compress them to a certain degree.
Squeezing out more air during expiration, the second method of improvement, involves (1) more effective use of the primary muscles of expiration – the abdominal group (rectus abdominis, internal and external obliques, and transversus for those who want anatomical names); (2) greater use of the accessory muscles – the intercostals, scalenes, and other neck muscles.
If the volume of the chest cavity is increased, the lungs will automatically expand to fill it – thus increasing their capacity. The muscles of expiration then take over to control both speed and minute volume of air outflow.
Hope this makes sense, without too much medical jargon.
Dr. Bill Dawson, bassoonist and teacher
IDRS medical consultant
Past President, Performing Arts Medicine Assoc.
Author of "Fit as a Fiddle: The Musician's Guide to Playing Healthy"