The longer you are stuck in a rut, the more you are inclined to think that you've hit the edge of your abilities. You've touched the genetic third rail and so there's no further progress possible, right? Hogwash. Every runner, at some point, experiences doubt. Change your attitude. Believe in yourself. Go back to your progress as a runner and focus on the positives. Your breakthrough may be one race away; it could be years away. The time frame doesn't matter. What does matter is that you recognize it's out there. Go find it.