Muffin Man:
The academic proram here is pretty demanding. None of the sponsored preps here (USAFA, USNA, USMA, or USMMA) are asked to play a varsity sport. On the other hand, IF you can balance a tough class schedule AND participate in sports (what it's like at a service academy) - more power to you.
As to the type of sport (my opinion only) playing a team sport is better than an individual sport (active-duty military fights as a "team"), being a leader of a team sport is better than just participation.
The only self prep athlete we had appointed this year was a baseball player to West Point. I'm talking about the college program - not high school.
Does this help?