Lie on your back with your knees bent. Place your middle three fingers in your tummy button. Your fingers should be pointing in the direction of your toes.
Relax your abdominal muscles and lift your head. If you are holding your abdominal muscles in as you check it will give you a false reading as this will make the diastasis appear smaller. The muscles will get closer together the higher you lift your head. To get a more accurate reading, it is important to check yourself when you first start feeling the muscles coming together. You might have to come up and down a few times so you can feel how the muscles work.
If you don’t feel the two ridges of the muscles with 3 fingers you may have to put more fingers in. If you see the football- like ridge you should start by using 4 to 5 fingers.
You may even have to use 2 hands if your diastasis is very large.
https://www.youtube.com/watch?v=c6jqyxyonGA