My worst is hands down legs. I recovered from a broken bon in my foot. It was pretty nasty break couldn't walk, not even walking boot for over two months. Memory is bringing her back now but not there jet, when cast came off it looked like a 12 year olds leg it was sad. When that's normal again, maybe arms I'm pretty long armed
My calves. I have VERY strong calves, BUT, I just don't have the genetics to have large calves. YOu name it, i've tried it. I work them twice a week now, that seems to work the best. I used to train them 3X a week, but it didn't matter.