I had L3-4-5 replaced a year ago. Even with the constant pain gone (thank God) i still cannot walk more than 1/2 block before my back starts hurting at the waist and pain continues down my legs and I can't move on. I need some excercises for my core that does not include walking. I am very flexable forward but not bending backward. Suggestions? Oh, I have Lupus that is affecting connective tissue and nervous system.