I'd like to extend an invitation to my fellow members to share their anecdotal misadventures with training equipment. I'll happily start. A couple of years ago I had a standing Bob bag in my room with about 350 pounds of sand in the bottom. One day after watching Ong Bak I thought it would be a great idea to try a flying knee on it. Somewhere in between jump and contact I realized that there was nowhere for the bag to go but into the drywall. So I bailed sort of. My knee still made contact moving the bag in a lever like motion but I absorbed most of the force with my hands against the wall. I then landed only to find Bob's face springing back into mine. I still had to patch the drywall.