Zone of Apposition

Improving the zone of apposition helps the diaphragm support breathing and pressure regulation with less reliance on accessory breathing muscles. The zone of apposition is the amount of diaphragm tissue that lies directly against the inner rib cage. The zone of apposition is always present to some degree, but its extent changes. Rib flare reduces the zone of apposition by lowering the diaphragm relative to the rib cage. Pulling the ribs down, back, and inward increases the zone of apposition. A full exhalation with the rib cage dropped creates a maximal zone of apposition. Full exhalation can increase diaphragm tissue contact by closing and anchoring the lower rib cage. Controlled exhalation helps create the rib and diaphragm position targeted by the 90-90 hip lift. A lifted or flared rib cage tends to reduce diaphragm apposition against the rib cage. Maintaining a maximized zone of apposition all the time is unnecessary and can be counterproductive.