Deep breathing is diaphragmatic

Deep breathing is slow breathing as compared to the rate of normal breathing. It also uses higher amounts of air per breath and is therefore forced diaphragmatically. The diaphragm is the most muscle to use make the lungs breathe large amounts of air per breath. The figure and the video below show the mechanical action of the diaphragm muscle in expansion and contraction of the lungs in the chest cavity to pull in and push out large quantities of air in breathing.

Beginners may use the abdominal muscles initially to help in the pumping action of the diaphragm. The goal however is to use the diaphragm alone as it gains strength to act like efficient bellows without the use of the abdominal muscles.