Knife

If these things do not occur, it may take minutes before a person bleeds out (exsanguination). In most cases, it would take transection (complete severing) of the thoracic aorta to cause enough hemorrhage to cause unconsciousness in about 4 to 5 seconds. For an average 70 kg (155 lb) male the cardiac output will be about 5.5 l (1.4 gal.) per minute. His blood volume will be about 60 ml. per kg. (0.92 fl oz per lb) or about 4200 ml. (1.1 gal). Assuming his cardiac output may double under stress, his aortic blood flow can reach 11 liters (~2.8 gallons) per minute. If a wound totally severed the thoracic aorta, it would take about 4.6 seconds for him to lose 20% of his blood volume. This analysis does not account for oxygen contained in the blood already in the brain that will keep the brain functioning even longer. Of course, hemorrhage is cumulative, so, over time, many small minor cuts may cause as much blood loss as one major cut. Therefore, for someone to be quickly stopped as a result of bleeding, large arteries and veins must be cut, and even then, it may take several seconds or minutes before the person is incapacitated. Knowing this, about bleeding, some knife fighters advocate focusing knife attacks the structures of the body that allow hostile movements to continue. They seek to disable the attacker by targeting the muscle groups, tendons, etc. that control grip and arm movement. As with hemorrhage, structural damage is cumulative, but also, as with hemorrhage, it may take many cuts before any appreciable damage is done. Attackers do not stand around while you carve on them; they are trying to kill you, so you do not have a lot of time to mess around.

As discussed above, any of the three types of one-shot stops is difficult to achieve using a knife. However, if you combine blood cuts and muscle cuts, along with the pain they cause, you may succeed in quickly stopping an attacker.