Started exercise you risk for health diseases will go down and you will not go into depression you there is a lot of good thing that come out of changing you lifestyle. I hope this helps
1. Make sure the sport they are playing, that the item can't cause a real injury
2. Make sure the surrounding area is acceptable so like no slippery floor, or marble floor
3. Make sure every kid is doing the steps correctly or game, if not, then teach them and separate from kids doing good.
( I don't know if you meant ruled steps, so I made some, this is just what I think, hope it's what you want. )
The answer is Both 1 and 3
Because emergency responders cannot enter areas that are still dangerous and because it it important to check for danger to victims and responders and assessing the situation is the first step taught in first aid course and the first step is actually to call the emergency assistance.