I do maintenance on industrial machinery. There is a certain machine in order to open and close it, you have to hammer on a ~5inch diameter target 10-20 times with a sledge. We had a new guy zoomie who threw out his back on his first swing and had to go to the doctor kek. He was stuck doing paperwork and non-heavy lifting for like 3 months until the doctor (and foreman) cleared him to touch a tool again.