You are saying he is very out of shape, it is possible that he just doesn't have the muscle strength to canter properly just yet. Work on lots and lots of transitions, trot until he has a nice balanced trot then ask for the canter. Canter only a few strides and then back down to the trot until he is nice and relaxed/balanced again then repeat. Keep practicing your transitions until they are nice and smooth and he is able to do them without getting strung out either way then start to slowly add more canter strides in.
5Likes
