I had a student one year, dirt biker, so he was used to putting a foot out in the corners, we were able to break that habit, and this kid rode great all day, knew what he was doing and easy to teach, he was doing the slalom course in the afternoon, and the back of the bike happened to skip out slightly on him and he reactively dropped a foot, it took less than a second for him to compound fracture his ankle, a few plates and screws and he came back the next season and took the course again and killed it.