One of the talking heads on CBC Sports mentioned that concussions are substantial in women's hockey at the highest level. Full body checking isn't allowed in women's hockey so, if this claim is true, it points to concussions being caused by collisions NOT involving hits to the head.
I've seen pseudo-science claims saying there are proportionally more concussions in women's hockey. The problem is that since all hitting is banned, and testosterone-driven bravado is less prevalent, concussions actually get reported. Everyone now knows they are notoriously under-reported in men's hockey.
And tackling and blocking should be banned in football, and overhand pitching should be banned in baseball.
Call me stupid (or whatever), but when I graduated from touch to tackle, I never understood why - except that that was the way they played on TV. Once we ban hitting from hockey, we can look at the need to upend people in football. As for baseball... is that a sport?