Standing on a horse during hippotherapy is just one example of using a dynamic surface to promote body awareness, postural control and strength. Start out providing lots of physical assistance while horse is standing in place (yet, is not stationary), then add performing while horse walks. Some of my clients were able to turn a full 360 degrees in place and as you see in the following posts- perform fine motor activities that further challenged their physical skills.
If you do not have a horse available- try offering other dynamic surfaces such as standing on an air mattress, whoopee cushion, rocker board, trampoline, platform swing, etc.