Normally a participant in a sport – even a child – assumes the risks inherent in the sport and therefore can’t sue to recover for injuries. There are some exceptions to the rule. For example, You don’t “assume the risk” of a danger you would not normally expect to find in the sport (example: a puddle on an indoor basketball court).
So here’s a summary of that new case: In Cvijenovich v Beacon Kids Wrestling Club, a child wrestler’s opponent suddenly did “an illegal or unreasonably dangerous wrestling move” causing him injury. An illegal or dangerous move like this is not covered by the “assumption of risk” doctrine because no one joins a wrestling club with the expectation that illegal, dangerous moves will be used. Participants assume the risk only of legal moves.