As with any college application essay, I think that there might be some specific elements that you must address. Paying attention to these and to the insight of those who will be editing your essay will be of vital importance. These insights probably trump anything generated here. However, I think that before writing the essay, you engage in some thought about what your football experience gave to you. What did you gain from your football experience? I think that reflection in this realm might be essential. Thinking about the sacrifice both in physical and emotional terms might be important here. Reflecting on what it was like to be a part of a team and thinking about the idea of sacrificing some of your own personal sense of self for something communal and larger could be important to bring out in your essay. I think that the college essay here is seeking to understand how your time in football enhanced your own sense of identity and what lessons you learned from your time in football. Bringing out the personal growth that happened as a result of football will be part of your essay. In bringing this out, your essay should take form around this aspect of your own characterization.