The knee-on-belly position is a particular pin where the shin or knee is driven into an opponent's torso as they are lying on their back while you also simultaneously control the opponent's shoulders and hips on either side. The other leg is held back as far away as possible to avoid your opponent grabbing it. The sport-safe version of this position requires the shin and knee to be placed specifically on the opponent's belly so as to avoid injuring the diaphragm, sternum, ribcage, or neck. More injurious versions of this position placed the shin on exactly those critical areas other than the belly, making them unsafe to practice during live rolling and generally only safe to practice while drilling.