My muscles are apparently tougher then stainless steel and bone. I was in an accident and the bones in my right forearm decided i should have a second elbow in the middle. The bones popped out and back in. They decided that to fix it i needed to have metal plates and screws put in on both bones. A few weeks of barely using it went by and the x-rays showed everything healing nicely. Then i decided to stretch one day and i broke it again, ripped the plate in half, and the bones with it. Had to go back in for new plates and screws. I still wont lift heavy weights with it by itself (over 100 pounds, i used to curl 125 pound weights)