Why training the core, achieving a flatter tummy and/or healing Diastasis Recti is not as straight forward as the Internet sometimes makes out....
Two of the muscles of your abdominal wall (your transversus abdominus and internal obliques) are the deepest muscles and function to STABILISE your trunk. Whereas another two (the rectus abdominus aka the 6 pack, and the external obliques) lay nearer the skin surface and function to MOVE your trunk. Very different roles but all of which attached to the midline (the linea alba).
Take a moment to visualise the layout of these muscles.....
If these stabiliser and movement muscles are imbalanced the body can experience pain, dysfunction and tightness and you will struggle to achieve a flatter tummy.
If when you sit up you experience abdominal doming this could possibly be Diastasis Recti (left pic) or an overactive Rectus Abdominus/RA (right pic).
In the right pic, the deeper core muscles haven't stabilised before movement. This is a sign the RA is dominant and your deep core isn't kicking in like it should to flatten your tummy as you sit up. This doesn't necessarily mean you have a Diastasis Recti (which is a bulge BETWEEN the RA as in the picture on left).
Many women who have dominant RA, continue to do more and more ab exercises which continue to make this imbalance worse causing back/pelvis/hip pain and also pelvic floor issues. In this case the goal is to release tension in the RA and re-connect with the deep core.
On the other hand, the external obliques could dominate over the RA and deep core muscles. In this case, it could increase the risk of prolapse due to amount of pressure bearing down on pelvic floor because of EO's squeezing in from the sides (a sign of this is a pinched in waist angle and a narrow and stiff ribcage (narrow infra-sternal angle). Goal = release the ribcage, reconnect with deep core THEN strengthen RA.
In another situation, the internal obliques could dominate over the RA and external obliques which could cause the ribs to flare wide (wide infra-sternal angle), compromise breathing (and thus the pelvic floor) and cause a wider Diastasis due to tugging on the midline. The goal here is to not only reconnect with the pelvic floor and transversus abdominus, but also release the internal oblique and THEN carefully strengthen the RA and external obliques.
IF your issue is Diastasis Recti then this is more complex to heal (but not impossible!), and VERY individual from woman to woman, but it starts with fixing breathing technique, identifying posture issues (such as pelvic tilt, limited upper back mobility, flared ribs, weak glutes, pelvic floor tension).
Commitment and consistency is key and patience to explore and learn more about your body is essential.
It's not a quick fix situation and there is no magic exercises to heal a Diastasis and/or achieve a flatter tummy, but it is possible to resolve with regular monitoring (oh I can't wait to open my treatment room again!). But in the meantime, please get in touch if you need support and guidance remotely in the meantime!