Thank you for getting back in touch with me. I teach Pilates which is primarily all core (back, spinal muscles, & ab) exercises. My back muscles are very strong, if they were not I would be in even more trouble. I have spoke to several Physiotherapists and have researched all the exercises they do & the exercises we do in Pilates is identical. Examples: Prone swimming, bridges, ab series, planks, push-ups, etc.