No matter who you are, no matter where you are in your training, you will come to the point where you think you have hit the wall of your limitations. It doesn't really matter if it's running a mile in four minutes, or finishing a 10k in under an hour. At some point, you have to make the decision to do more than you ever thought you could. No matter what the voices in your head are telling you, when you keep going, something magical happens.