Structural functionalism holds that every aspect of our society has a certain function. All parts of our society help to keep our society stable and cohesive. By contrast, social conflict theory holds that social institutions like sports are used by the dominant groups in our society to hold the lower groups down.
A functionalist might say, for example, that sports teaches important lessons that people in our society need. It teaches perseverance and teamwork and discipline. By contrast, a conflict theorist might say that sports are used by the dominant class as an "opiate." Sports are used to provide an outlet for the aggressions and frustrations of the masses so they do not rise up against those who unfairly dominate them.