Inhalation is passive (relaxed "use" of the diaphragm). The more relaxed this muscle and the more we use intercostal chest muscle to expand vital capacity, the more we are able to prepare the body to receive that MOST important first step of inhalation. What we do with that air and how we can use it IS determined by how the rest of the body is set up for action. If the body is not adequately prepared, then suck we will. So there is important coordination between relaxation of the upper airway while the lower airway is being cocked and loaded for discharge. How much discharge force is needed can be amazingly reduced by how we can relax all the is distal to this force.