My son's team has a kid who got a concussion playing on defense during a game. He and another kid on the team collided going for a flag. He missed a week of school and two or three weeks of games. The week after this kid got his concussion, my son has a collision with a kid on another team - my son's mouth smashed the other kid's head. You should have seen the fat lip my son got. It was probably the biggest I've ever seen, including major swelling of his lip and gums. I would be surprised if the other kid didn't get at least a minor concussion.