I have a client who birthed twins 21 months ago. Since having her twins, she cannot "feel" the left side of her abdominals. She can't do 100s, and exercises like plank or plank to pikes cause her to feel like her abs are going to "fall out." While she did have diastasis recti, she is managing it well and it doesn't protrude anymore. The problem is she can't feel her abdominals engage. Any tips?