Connie Hi Connie! In classical yes, we learned the 1st exercise in a posterior tilt of the pelvis, but I find it very challenging for my students to do the second exercise flat back when the pelvis has been locked in a posterior tilt. Also, I never want the lower back to collapse. Neutralizing the pelvis, you can lengthen the lower back, get deeper into the powerhouse, and create the “C” in the thoracic, which is better for the spine.