Equivalent of boxing and other combat sports, I suppose. Equipment that makes a sport almost requiring high speed collisions on every play safe doesn’t exist.

Not combat sports in general, but the combat sports where hitting the head of the opponent is a valid method for winning.

Boxing is by far the worst from this point of view, much worse than the combat sports that allow knock-outs but also have other alternatives, like MMA.

Combat sports like judo or fencing are much safer than American football.

Boxing is far worse than other combat sports because of the thick gloves, and plenty of combat sports don't involve significant head impacts at all.

The equipment to make it safe is the problem - it allows you to take orders of magnitude more blows to the head. There were many people saying that to improve the safety of football, you should get rid of helmets entirely.

Padded helmets in football and padded gloves in boxing serve the same purpose as having filters on cigarettes. Filters on cigarettes allow you to smoke a lot more, and a lot of the stuff that is worst for you is not filtered out.

They should remove all padding and safety equipment, and institute severe penalties for any contact that could cause injury. The sport would probably become sane, but people like the violence, so this isn't going to happen.