My chiropractor showed me how to work the back muscles standing still, kind of like a reverse sit up. Take a stiff brush or little nail you may have to experiment but what you do is go from their between their front legs and run the item along their belly and the goal is to get them to pick their arch their back, and hold it for a second, then do it again. Start out with three to five reps and add a little every day. My horse knows to pick himself up with the touch of my thumb up under his barrel. I do it before I ride, and if I don't ride I do it about ten times while I am grooming, before I turn him out.