Normally adjectives in English are usually singular: -You say "bean soup" even if there are many beans or many kinds of beans in the soup. -"a science education" even if there are many scientific disciplines being studied. "Sports", however, is an exception. We usually make it plural: "A sports bar" , "a sports team" , "Sports medicine" etc.There are a couple of other nouns like this, such as "media" (plural), versus "medium" (singular). I can't find a good list at the moment though.

We generally use the plural 'Sports' as there would normally be more than one sport being studied. So, 'sports school' singular and 'sports schools' plural