A strong cylinder for core stability requires a large top (diaphragm), a large bottom (pelvic floor), and symmetric side compartments (abdominal wall musculature).

“so if the diaphragm formulates the top of that cylinder what makes up the bottom of that cylinder so the bottom of the cylinder we're looking at the pelvic floor which is an area of musculature basically where we the babies come out and that musculature will coordinate the regulation or management of intra-abdominal pressure that is created with the descending of the diaphragm so the diaphragm three three main functions respiration but there's also obviously this a huge postural function where it descends even more and creates an intranal pressure so that uh when that pressure is created that diet the pelvic floor will eccentrically load meaning it's active but musculature is active but stretches you can think of it like wind blowing into a sail where the wind blows into the sail it opens and activates and then it holds and maintains the pressure but then at the same time we have the entire abdominal wall which consists of the the rectus muscles our six-pack muscles our oblique musculature which is musculature that uh crosses the body comes up and has attachments onto the thoracic cage of the rib cage and then a big one called transverse abdominis which wraps around from the the back the thoracolumbar fascia around to the front so as that diaphragm descends to to facilitate a stabilizing function that”