Sports are certainly a big part of daily life at prep school. Coaches and teammates are likely the people athletes will surround themselves with, and spend the most time with, while at school.
Especially these days, sports are a common reason to investigate prep school. They can also be a big factor in getting admitted to prep school and in paying for prep school.
Sports can be broken into two groups. One, high profile sports. These are football, basketball, and ice hockey. Two, lower profile sports. These consist of all other sports.
Generally speaking, high profile sports get higher priority in the admissions process. Knowing this will help you understand how your application is being perceived.