This is a cue that I’ve been seeing a lot lately, and rather than be frustrated I thought I’d be proactive and do some teaching over here.
A muscle that’s constantly contracted is not a strong one, just a tight one - so let your belly go. Stop holding it in! This is so important for optimal core function - when you hold your belly in you’re preventing the diaphragm and pelvic floor from working together in harmony.
While I understand that this cue is incredibly common and isn’t necessarily incorrect, it’s not useful because it’s simply just not clear, and for people who don’t know any better they might think they are supposed to be “engaging” and “sucking in” the abdominals with movement.
However, bringing your belly button to your spine using your abdominal muscles isn’t making the muscles stronger - it’s just creating pressure up and down through the core canister - up to your diaphragm and down to your pelvic floor.
Some intra abdominal pressure is necessary to support the spine, but too much creates unsafe pressure on the pelvic floor which puts postpartum mamas at risk for prolapse and other pelvic floor dysfunction issues.
Instead of bringing belly button to spine using your abdominal muscles, practice doing this with the breath. Inhale through your ribcage, and then as you exhale imagine breathing out through your belly and the deep abdominal muscles called the transversus abdominis, or TVA. Picture your hip bones moving closer together on the exhale. The TVA and pelvic floor work together - as you exhale you can work to imagine your belly button lifting *up* toward your sternum rather than in toward your spine, and picture yourself growing taller. At the same time as the TVA exhale breath, focus on a small pelvic floor lift. THIS is a proper kegel, and how to protect your core canister postpartum *and* how to work to increase tension in the linea alba, the connective tissues in the abdominal wall where diastasis recti occurs. Strengthening the tissues is actually more important than closing the gap all the way. FIT MAMA goes through this in tons of detail with all of the exercises that you can do to create a stronger body and more functional core in a super safe way.