I guess my back hurt the most. And my neck. Like holding your head up doing 100s. I can do the abs part, but can't hold my head up without pain. The fact that no matter how long I kept trying, my back still lifted off the floor, out of "imprint" when doing some of that stuff.
The yoga classes I take are fairly easy, I guess. Yet, I have seen improvement since I started. I am very flexible, so that's not it. I'm just weak, lopsided, due to untreated scoliosis, and all my other assorted sports injuries. Heck, PT only helped me temporarily and I was religious about my "homework." I still do all of that, 4 days a week.
Maybe I would feel better if I stopped all of this exercise stuff .