Hardworker92 - YES! Sports definitely helps with your application to West Point.
About 90% of all cadets were varisty athletes in high school and nearly 90% were letter winners. Over half were team captains - so you will be in good company!
I see you are a cross country runner and swimmer - that is terrific. If you are interested in pursuing either on a D-1 level you may contact the coach(s). On the club level West Point has water polo, triathalon and marathon teams.
West Point looks for a student who embodies the scholar/leader/athlete model. It sounds like you are well on your way, from your other post.
Most kids are not exceptional at all three of those - that's ok. They like to build a class of those who are athletes, leaders and scholars and even form their companies from a mix of cadets.
Go here:
http://admissions.usma.edu/startyoung.cfm
sign up for the mailing list and West Point will send you lots of good information!
Also you can soon apply for a spot at the Summer Leaders Seminar. This is a great way to see West Point up close and personal and get a start on your application!
http://admissions.usma.edu/MoreInfo/summer.cfm
The application will be up on Dec 15th.