I'm not an expert on how to configure the sport, but I can observe and say that accidents seem to be a part of it. The athletes are incredible, with the courage that they accept the risk of death, paralysis, and brain injury. These are really life-changing, life-threatening injuries, and the risk is extremely high.
There is no such thing as luck. It's a fancy name for being always at our duty, and so sure to be ready when good time comes.