What an Admin can do?

Hello, first of all, this is my first post, sorry for my bad english.
I'm developing a little App to management a G.Y.M/Sport center, this application has roles, i don't know what an Admin can do, i mean, he can has a list of employees, the admin can add class or create a new schedule, but that's it?
If somebody can tell me what an admin can do, because i dont have any idea.
Thanks.