Canadians invented it in the seventies because apparently even tetraplegia wasn't going to stop them hitting each other.
Fun fact: Originally called murderball, it was invented in Winnipeg in 1976 by five athletes with tetraplegia.
Settling pub arguments about who's strongest since roughly forever, and Stallone even made a whole film about it.
Fun fact: Spiral fractures of the upper arm are so common in the sport they have their own medical name.