The marathon is the archetypal struggle of the self to accomplish something beyond the limits of the human body. Many times, we dream that we are competitive, which is a sign of competence. However, other times we lack the ability to be competitive, because in our dreams, our waking limitations often accompany us. This may be particularly true if your colleagues and associates run in the marathon also, but more effectively than you.
Why are you in the marathon? Are you able to run it competitively?
Are your competitors familiar to you, or strangers?