I am going to assume you are going to do AFROTC as a freshmen. If that is the case, I wouldn't worry about sports, instead MAX the PFT, get involved in your unit. Inform them immediately that you have the intention of reapplying. Many kids think that will do harm, but it doesn't. A strong CoC will get behind you 1000% because they have the same goal as USAFA...great officers. It is not USAFA vs ROTC. It is USAFA and ROTC for the good of the AF!
Also keep your mind open to AFROTC, in other words don't get tunnel vision. Many, and impo, probably the bulk of kids that get a TWE do not reapply a year later. It comes down to the person, and the unit knows that.
Work out all summer in all types of weather. Study the AFOQT. Get your nomination packages done early (MOCs like reapplicants). This way when you show up in August you can pay more attention to your academics, and pull strong grades that 1st semester.
OBTW, 1 more reason to tell the CoC asap is that you will want that ROTC nom. No quicker way to tick off the unit is to keep it secret and drop the bomb 2 weeks before the due date that you want them to support you for the nom. They have to sign their name to that rec., and not a lot get charged to ROTC. Stronger the rec., the better off you are from an appointment aspect before hitting the pool.