I don't know how, but i've never broken any bones besides my hand (boxer's fracture or sometihng the doc said) when I punched a door, twice. First time I didn't know I broke it, hurt like hell but I didn't know, second time a few months later I knew it had to be broken cause it was pushing through the skin. and doc informed me I broke it before cause of the new bone growth visable on the x-ray and the doc couldn't set the bone right either. Now my right hand is crooked.
Nothing really bad, just sprained my knees, ankles, hyperextended everything at least once, bit through my lip twice during wrestling that had to get stitched (couldn't smile for 2 weeks!) and cut the bridge of my nose from my football helmet coming down. Buts that really about it...