About 2 seasons ago, I had an absent-minded incident where I tried to brace a fall with just my left (non-dominant) thumb.
I was at base camp, just strapping my back foot onto my snowboard and about to queue for the first lift of the day. Somebody passed by me and I sort of lost balance and started to slowly fall forward. I knew I was supposed to brace the fall with my forearms and stuff. But...
For reasons beyond myself, I decided to ONLY use my left hand, left thumb to be precise to brace the fall. HOLY CRAP I immediately felt something. The thumb/joint immediately swelled up and I was in agony. And the day didn't even start yet!
Turns out I have a partially torn ULC (Ulnar Collateral Ligament). I'll need a surgery to fix it. But it's hard to find a 2-3months time slot where I know I won't be using the hand. Luckily, I can't damage it anymore than it already is unless I stress it, it just aches to no end.