I have been writing about the dangers playing American football due to the increasing number of reported cases of brain injury due to the repeated concussions that American football players experience, and argued that there are strong grounds for schools and colleges not fielding teams since educational institutions should not be encouraging young people to run the risks of permanent damage by seeming to endorse a dangerous activity. If as adults they want to play, there is little we can do except not support them.
Mark Frauenfelder shares a gif showing a slow motion video what happens when a boxer gets hit in the face. The massive distortions that ripple across the face like a wave are quite frightening to see and, in a sane world, would result in people giving up boxing altogether.
It struck me that a similar video showing what happens to football players when they get hit may have a similar sobering effect. The catch is that we cannot see what happens to their faces because of the helmets.