Question: I have a medical condition that keeps me out of sports. I have done other extracurricular activities--including lots of community service. Will the lack of athletics on my record hurt my admission chances at the most competitive colleges?
The fact that you don't play sports in unimportant. Athletic participation is a plus in the admission process for that small percentage of students who are good enough to continue their sports on the college level. For all others (and that's the vast majority), athletics on the high school record are no different--or better--than any other extracurricular activity. That is, they show admission officials that the candidate has interests outside of the classroom. However, admission committees see so many athletic listings on applications that it's often a refreshing change of pace to see something besides sports. In other words, there's more space on college campuses for someone who cooks a great souffle or plays a mean bassoon than there is room on the soccer and basketball benches.
It's probably a good idea to explain your medical condition--and its effect on your athletic career--on your applications. This explanation should also include--if appropriate--reassurances that your health condition will not inhibit your ability to be successful in college, even if you won't be the starting quarterback.