The sprained ankle - stress fracture is possible. And with kids, they often lie about being fine because they want to play, when really they arnt 100%.
The raised court is an interesting theory. I'm naturally clumsy. Ive fallen a millions of times. Yoga has helped. But slight slope can throw my balance off if its unexpected.
I'm gonna YouTube Joe Thiesmman's injury as I was in 7th grade and probably didnt know about it.