By definition, a person can only apply to one place Early Decision, and if you are admitted, you are committed to going there. You sign a statement that says that if admitted, you will pull any other applications. So, that's why coaches as recruits to commits to applying ED, and in return the coach helps your application through admissions.
Some schools have Early Action (EA) instead, which is early but non-binding - that is, they tell you early if you got in, but you are not required to attend. You have to read the admissions material carefully to figure out which it is.