I’ve seen once heard of several concussions from rowing. Catch a crab and the oar comes back heaaavvy

Valid point. I’ve luckily only seen these get caught under rowers rib cages and/or launch them out of the boat, luckily only bruises and sprains.

But I’ve been knocked unconscious twice in skiing and suffered a third concussion as well. Another concussion from swimming into the wall and from falling off gymnastics equipment.

Perhaps there is some reason for concern after all…

In my experience catching a crab is entirely avoidable.

I mean I totally agree that an experienced rower will never catch a crab under normal circumstances, but as I type that I remember that the one I witnessed was due to a rower getting heat stroke in the tail end of a 5k - so, I guess there’s the counterexample.

Avoidable but expected that beginners will. Concussions are rare though, not the likely outcome.