Hello fellow instructors!
If a client comes to you 2 years post pregnancy with a 2 finger wide Diastasis, how do you help them rebuild their abdominals and close the separation. Is it even possible to close more at this point? I know what exercises to avoid but what exercises should we focus on? Also would you suggest using a waist trainer at this point or is it too late. I would love any on all suggestions for modifications and information on Diastasis Recti.

I see you posted a while ago, but for what it's worth...

The first thing a client must work on when hoping to close a diastasis is learning to breath in a way that allows their ribs to move tortionally (expand) to the back and sides (rather than breathing into the belly or up into the shoulders and neck or down into the pelvic floor) - this will help to decrease the intra-abdominal pressure contributing to the diastasis. Next, aligning the bottom anterior true ribs over their ASIS will help to properly distribute load to their abdominals and again decrease intra-abdominal pressure. Regaining yield in their obliques and QL will help, as well. I would also recommend adding collagen to her diet to help repair her connective tissue.

Using waist trainers to help a diastasis is controversial - it can hinder the body's efforts to stabilize and strengthen on its own, and with a 2-finger gap I would'nt bother unless she feels very unstable without it. At a 2-finger gap, I would be more concerned with the depth of the diastasis and the integrity of the connective tissue over the width... can your fingers sink more than 1cm down? Does she also have digestive issues?
I highly recommend the book "Diastasis Recti - The Whole-Body Solution to Abdominal Weakness and Separation" by Biomechanist Katy Bowman for a helpful understanding on why diastasis happens and how to heal it. Good luck!