I had a TB mare that I got from a place that had her kept in a stall all the time. She had a sway back and was sore a lot. When I got her, I gave her a special time every day that I would take her into the sand arena on a lunge line and she would roll. At first she could only roll on one side, but after a few weeks she started rolling over to the other side and now her back is much healthier and less sore. I'm able to ride her again :)