For a horse to be textbook correct when spinning, he should plant his inside hind foot. Horses that tend to plant their outside hind foot do so because they’re sucking back too much. While it’s generally a good thing to have a horse thinking “get back,” in this case, you want to get forward on his mind. To correct this problem, first make sure you’re not causing the horse to suck back by pulling back on the reins and causing the horse to back up or putting him in so much of a bind that he can’t move. You just want enough pressure on the reins to stop the horse from walking forward.
A great way to remind the horse to step forward is by trotting him out into a small circle after he takes a few correct steps and then spiraling him back down into the spin. Ask him to move his front around his rear, and as soon as he takes one correct step, trot him out in a circle. Then spiral him down into the spin again. Asking him to actually move out will help him think “forward” in the spin rather than stepping back.
