An athletic diaphragm allows for proper lung ventilation and prevents compensatory use of abdominal muscles during breathing, which can wear out the body and compromise the spine.

“so you've improved the cylinder so the diaphragm pumps up and down inside the cylinder to allow you to lung ventilate if you don't have that athletic diaphragm you're entraining your abdominal muscles the oblique muscles to the breathing effort while you're running it wears you out it also compromises your spine so you need those muscles to form a girdle and hold it all together”