People need to understand the power of Executive Orders, and what he can and can't do with them. He can order federal departments and administration staff to do stuff. He can't order private citizens to do anything. Nor can he order corporations or non-government organizations to do anything.
So this EO is clearly outside of his jurisdiction. It is the kind of thing that people ought to resist. It should be challenged in court. I am sure there are sports organizations who will be happy to comply voluntarily, but any that don't feel like complying should just go ahead and do what they want to do, because it will be overturned.
Don't hand the guy any more power than he is legally entitled to.