It is very tempting to think that this is the point where your performance limit has been reached. While there is the possibility of having reached your potential, more than likely, you will still have a long way to go. However, if at each point of stagnation you believe you have reached your physical limit then you probably won't strive to get better. It's in these times of stagnation and lack of progress where belief is of critical importance. Your belief can carry you through the tough times, such as injury or sickness, while those who don't believe may give up.
Psychological barriers are far more common in running than physical barriers.
Yes, we all have our physical limits, but few ever reach them because of the psychological limits, which we place on ourselves. This spring make it a goal not to limit yourself by the way you think. Believe in your physical ability and believe in your mental ability. You must have physical ability or you wouldn't even be involved in the sport of running. Just think of how many people in our country don't run and never will run.