How the core works - the piston

The piston analogy originally comes from Julie Wiebe. It is a great analogy to help patients understand how their core relates to their breath. As you exhale, your diaphragm and pelvic floor are naturally shortening - the piston is moving up. Performing a pelvic floor and core contraction on the exhale makes it much easier to engage the muscles, because you are joining in with the natural movement of the core. When you inhale, your diaphragm and pelvic floor move down to help make space for the lungs tor fill with air - the piston is moving down. Trying to contract the pelvic floor on inhale is much more difficult, because it goes against the natural direction that the muscles are moving in. For this reason core exercises are performed on the exhale.