I think that participating college athletics is a big bonus, but like others have said, make sure your GPA/MCAT scores are as good as possible. Having poor numbers is a big deterrent from getting interviews. Being an NCAA distance runner did not make up for my mediocre numbers during this cycle. Fortunately I was accepted to a good school that I will be happy at. Will being an athlete help you get it? Yes, but it won't be the reason you get in.
Good luck for your application cycle!