When I punch the bag during training, my previously (4 years ago) broken ulna aches with each hard punch and will sometimes swell a little bit. There is a plate with 8 screws on my ulna as well. Is there a risk to rebreak or damage the arm somehow, or do I

After . After 4 years, whatever healing has occurred should be done. There are 4 possible scenerios: 1. The bone didn't heal properly. In this case, the hardware will eventually break. Usually this happens suddenly with severe pain. Sometimes it breaks with only a slight motion. Depending on the thickness of the plate, 4 years may not be an unreasonable timeframe. 2. The hardware is irritating the tissues. Sometimes the tendons that glide over the plate get irritate and cause pain. Sometimes we don't know why hardware is painful. The hardware can be removed, but you have to give time for the screw holes to fill in with bone before resuming a punching bag. 3. The plate is causing a "stress riser"--a weakness in the bone in relation to the plate that can cause a fracture. 4. The symptoms are not related to the previous injury. You could have tendinitis, a tear in cartilage at the wrist (tfcc), or another problem. I would recommend seeing your orthopaedic surgeon and having x-rays of the forearm.