What is the worst injury you have sustained during training? Although they didnt happen to me, the worst we have had is a broken wrist and a broken rib. The only reason the person got a broken rib was because he had a tempory 'mind blank' and instead of moving off the punch he went right into it, ouch.
Worst for me was ruptured bicep, from a leg trap on a very big guy -- I should have used a different type of grab, or let go sooner (or dropped him to the ground faster). Live and learn!
broken handf it hurts to get hit in the hand with a kendo stick only try traditional swordplay if you know how oww...... my hand still hurts
A split lip and shattered front tooth when a defense against a kusarifundo when wrong. I had a lot of respect for a kusarifundo after that happened! Its one of the greatest weapons to use to trap other weapons and limbs. Other than that nothing serious.
Outside of training I've chipped a tooth and had a boxer's fracture from fighting. In training the worst was a torn trapezius, but that was wrestling and not really MA related. Getting kicked repeatedly in the nuts and chopped in the bicep by Shunshifu and Shifus isn't too pleasant I will admit. But those are when we are practicing techs and I don't think it counts.
Nearly lost my right eye From Katana wound - div in training was using a live blade - to be fair it was lucky for me, almost invisable scar from the 4 stitches I had. Lucky me!
I broke both my big toes during my black belt test, and had to finish with my poomse. Thank god for adrenaline-- as soon as the test was over, I realized that I could barely walk. Darn toes still hurt me, almost a year later, but dit da jow has helped immensely.