Knife Stopping Power

knife In a previous PDN article, I explained the logic of my Martial Blade Concepts (MBC) system of defensive knife tactics. A key element of that logic was the focus on achieving reliable, predictable “stopping power” with the type of knife you’ll typically carry on a daily basis. In this article, I’d like to take a closer look at the concept of stopping power and the best ways of achieving it with an edged weapon.

To shooters, “stopping power” means the likelihood of a particular caliber or round to incapacitate an opponent when he’s struck with it. It also relates to the probability of shutting down an attacker by targeting specific areas of his body. For example, high-center-mass hits are generally more reliable “stops” than shots low in the abdomen, and shots to the head are even better.

Although typically associated with firearms, if you really think about it, stopping power is actually the objective of all weapons and tactics used in personal defense. In a critical incident, incapacitating your attacker is what eliminates the threat and keeps you safe. Lethality, while a potential result of the application of a weapon, is not synonymous with stopping power. If you inflict a mortal wound on your attacker, but he lives long enough to kill you or cause you serious injury, you haven’t accomplished your real goal.

A cut to the triceps muscle or the triceps tendon just above the elbow eliminates an attacker’s ability to extend his elbow. It also targets the musculospiral nerve, which leads to the radial nerve and controls the thumb and index finger. Damaging these structures severely limits the attacker’s ability to wield a weapon.

A cut to the triceps muscle or the triceps tendon just above the elbow eliminates an attacker’s ability to extend his elbow. It also targets the musculospiral nerve, which leads to the radial nerve and controls the thumb and index finger. Damaging these structures severely limits the attacker’s ability to wield a weapon.

With this basic logic in mind, let’s consider the stopping power of the knife. And, in my opinion, the best place to begin to quantify that is with actual knife attacks and those who have seen them or experienced them firsthand. If you talk to most law enforcement officers, corrections officers, paramedics, and trauma doctors, you will hear stories of people who have been stabbed—in some cases numerous times—and not only survived, but remained mobile and active during the minutes immediately after they received their wounds. In fact, recipients of stab wounds often do not even realize that they have been stabbed and can be totally oblivious to their injuries. Even if they are aware of them, the immediate physical effects of stab wounds typically do not disable the victim.

If we accept this as a common, if not typical, occurrence, then it would seem that the tactic of stabbing to the torso and expecting instant incapacitation would be ludicrous. Unfortunately, that’s not the case. Most of the knife systems taught today still advocate thrusts to the torso as an effective means of stopping someone with a knife. This belief is also regularly regurgitated by the all-knowing “experts” who pontificate on Internet forums. Reality, however, still dictates otherwise.

The turning point in my approach to knife tactics came about 15 years ago—after I had written a book on the topic. That book, Knife Fighting: A Practical Course, basically distilled the information that I had gleaned from the Filipino martial arts and military combatives and presented it in a logical, organized manner. However, it still advocated the traditional targeting strategies, which included cuts to the neck and stabs to the torso.

One day I received a call from a guy who had been attacked by his boss with a large, fixed-blade knife. In the struggle, he was able to cause his boss to drop the knife; however, that wasn’t the end of the struggle. The boss knocked the employee down and began strangling him with his bare hands. The employee, in fear for his life, grabbed the knife and began stabbing. Nearly 50 stab wounds and almost five minutes later, the boss finally bled to unconsciousness. While the coroner’s report confirmed that several of the wounds would, by themselves, have been mortal, the boss still didn’t “stop.”

My analysis of the incident ultimately helped the employee earn an acquittal on first-degree murder charges. It also marked a major turning point in my approach to defensive knife tactics—one that focused on real stopping power.

Cutting the quadriceps muscle just above the knee disconnects the muscle from the lower leg, destroying the attacker’s ability to extend his knee or support weight. This “mobility kill” is one of the most effective ways of achieving a decisive “stop”—and your safety.

Cutting the quadriceps muscle just above the knee disconnects the muscle from the lower leg, destroying the attacker’s ability to extend his knee or support weight. This “mobility kill” is one of the most effective ways of achieving a decisive “stop”—and your safety.

The bottom line is that stabbing someone in the torso, even multiple times, will not cause him to burst into flames and immediately cease all hostile action. If you don’t believe me, go online and search for “video” and “stabbing” and take a look at some of the incidents that have been captured on tape. Cutting a person’s carotid artery won’t do it either. The video of the hockey player whose carotid was cut by another player’s skate during the middle of a game is compelling proof of that.

So how do you stop someone with a knife? There are a number of ways that it can happen, but only a couple of ways that you can reliably and predictably make it happen. Based on my research, I have identified five primary types of knife stopping power.

Five Primary Knife Stopping Types

1. Psychological

Psychological stopping power is a “stop” that results from either the fear of the knife itself or the fear and shock that result from a wound of any type. Basically, the attacker shuts down mentally, even though the physical damage he suffered, if any, isn’t debilitating. Unfortunately, an attacker’s psychological reactions are highly unpredictable and therefore totally unreliable.

2. Blood Loss (exsanguination and hypovolemic shock)

Most knife systems advocate stopping an attacker by causing massive blood loss. Misguided historical references such as W.E. Fairbairn’s famous “Timetable of Death” fueled this misconception to the point that it has become legend. While exsanguination (“bleeding out”) can stop an attacker and can often be fatal, in most cases, it does not stop him quickly enough to keep you safe.

For example, Fairbairn claimed that severing a person’s carotid artery (one of the major arteries of the neck) would produce unconsciousness in five seconds and death in 12. Modern medical science, however, provides quite a different scenario. Even at an elevated heart rate of 220 beats per minute (a factor that Fairbairn neglected to address in his statistics), it actually takes an average of 68 seconds to bleed to unconsciousness with a severed carotid artery and 89 seconds to bleed to death. Sixty-eight seconds is an eternity when fighting with deadly weapons at contact distance and hardly qualifies as an effective “stop” in my book.

3. Damage to major life-supporting organs

Many people also believe that puncturing a major life-supporting organ will cause an attacker to shut down immediately. Again, if we consider the number of people who have successfully survived stabbing attacks to the torso, it’s clear that such an approach is not as reliable as we might hope. Also, physical stature and blade length both have very dynamic effects on the reliability of this approach. A three-inch blade (the kind you’d probably be carrying) has a markedly different effect than a seven-inch blade, especially when thrust into a 300-pound biker instead of a 125-pound crack-head.

Assuming that you were able to successfully target your attacker’s vital organs, there’s still no guarantee that he’ll go down immediately. Talk to deer hunters and you’ll hear plenty of stories about perfect shots that punched through both the deer’s lungs and his heart—right before the deer bolted and ran several hundred yards before dropping. Well, give that deer an opposable thumb, a lethal weapon, and a few tattoos for color and you’ve got a hell of a fight on your hands even after you’ve hit him with a killing blow.

4. Damage to the central nervous system

As with firearms, targeting the central nervous system—the brain and spinal cord—with a knife is an effective and virtually instantaneous method of incapacitating an attacker. The problem is that hitting such targets in the midst of a stand-up fight is very difficult. Typically, the spinal cord is facing away from you, and access to the brain must involve going through the orbital sockets or under the chin.

5. Structural stops

The final and most practical form of edged-weapon stopping power is structural stopping. In simple terms, this tactic consists of cutting strategic muscles and tendons to destroy specific motor functions. To move a body part, your brain tells muscles to contract. That contraction pulls on tendons—which are like cables—that pull on bones to produce movement. If a muscle is cut deeply enough, it cannot contract properly and the body part will not move. If a tendon is cut, the muscle and the bone are disconnected and, again, the body part will not move. The beauty of this approach is that it produces instantaneous results and can be selectively applied to specific body parts, if desired. A side benefit is that it does not have to result in life-threatening wounds.

Cutting the inside of the wrist or forearm can sever the flexor tendons or forearm muscles, crippling the fingers and destroying the attacker’s ability to grip a weapon. In the Filipino martial arts, this is known as “defanging the snake.”

Cutting the inside of the wrist or forearm can sever the flexor tendons or forearm muscles, crippling the fingers and destroying the attacker’s ability to grip a weapon. In the Filipino martial arts, this is known as “defanging the snake.”

Although many Internet experts will claim that this approach to stopping power doesn’t work, historical evidence from both Asian and Western sources suggests very differently. Perhaps the best-known reference comes from the Filipino martial arts, which have a very highly evolved edged-weapon culture. Their fundamental tactic is called “defanging the snake”—targeting the attacking limb to destroy its structure and function. According to their symbolism, the weapon is the “fang” and the arm wielding it is the “snake.” Removing the fang from the snake immediately eliminates the primary threat to the defender—the attacker’s weapon—and offers safety quickly. In situations where the application of lethal force is warranted and tactically necessary, it’s also a lot easier to “finish the job” when the opponent is already disabled.

In the traditional Filipino knife arts, defanging is typically accomplished by cutting the attacker’s wrist or forearm. The goal is to sever the flexor tendons that connect the forearm muscles to the fingers, destroying the attacker’s ability to grip his weapon. Cutting the muscles on the inside of the forearm can produce the same effect.

Martial Blade Concept (MBC) Structural Stopping Power

MBC takes this fundamental tactic of structural stopping power, sometimes also known as biomechanical cutting, and expands it. Based on detailed analysis of human anatomy and physiology, I determined which body parts allow an attacker to pose a threat and are most vulnerable to cuts with a typical tactical folder. I then validated this analysis by cross-referencing it with actual combative incidents involving knives, as well as industrial and home accidents involving serious, disabling cuts. The result is MBC’s stopping-power-oriented system of defensive knife tactics.

MBC has three target priorities that were selected based on irrefutable principles of human anatomy. These targets—and the reliable, predictable effects of cutting them deeply—are as follows:

The inside (palm side) of the wrist. As previously noted, cutting this area offers a high probability of severing the flexor tendons and/or the forearm muscles that power them. This immediately disconnects the fingers from the muscles that enable them to close and grip things like weapons.

The bicep and/or triceps muscles of the upper arm. To wield a weapon effectively, an attacker must have the ability to flex and extend his elbow joint. These muscles provide this function. If they, or their associated tendons, are severed or cut deeply, coordinated motion of the arm is severely impaired, and the attacker can no longer wield a weapon effectively.

The quadriceps muscle at the front of the thigh. The function of the quadriceps muscle is to extend the knee joint. That function is what allows us to stand up and support our own weight. It is also critically important in walking, running, or any other type of movement. If severed, especially in the first few inches above the knee joint, that leg can no longer support weight, and the attacker will literally drop to one knee. This “mobility kill” provides immediate safety by allowing you to create distance and escape.

bicep-cut In addition to offering predictable and reliable debilitating effects, these targets were selected based on the fact that they can be easily and effectively targeted with a small knife. To validate this, I conducted extensive cutting tests on limb-sized targets made from wooden dowels wrapped with pork roasts and covered with multiple layers of plastic wrap to replicate the resistance of skin. These targets were covered with typical clothing and then “attacked” with the type of tactical folding knives and small fixed-blade concealment knives that you would actually carry for personal defense. These tests conclusively proved that blades three to four inches in length can easily and reliably cut our priority targets to the bone and produce exactly the kind of disabling wounds necessary to stop an attacker.

The final advantage of structural targeting is that, in the process of attacking, your opponent literally extends these targets toward you. Compared to traditional targets like the torso, this makes them much easier to hit. Some critics of structural stopping claim that it requires surgical precision, but if you compare the surface area of our arm and leg targets with the torso and neck targets they recommend, you’ll see that there really isn’t much difference. And even if there were, the key point is that when our targets are cut, people stop.

The bottom line is that killing with a knife is vastly different from stopping an attacker with a knife. Effective knife tactics combine a thorough understanding of human physiology; a realistic grasp of the capabilities of the knife; and natural, easily learned patterns of movement. Properly integrated, these elements offer reliable stopping power. Anything less isn’t worth betting your life on in a fight.

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21 Responses to “Knife Stopping Power”
  1. CrahomPC

    Simple, yet so effective! An excellent read and a practice everyone should know. Thanks!

  2. Lance

    Great article Mike. As a practitioner and instructor of Filipino and Indonesian martial arts, I am a very strong advocate of limb destruction and ‘defanging the snake’. Amazingly, hitting/cutting all of those tendons and muscles can be accomplished with only a few short movements and steps within seconds. Well written my friend.

  3. forddk

    It was a great article, but my girlfriend said the groin is her first target. Not a bad idea!

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  6. Brian K

    Perhaps it is just the version that I am reading but under the section titled “MARTIAL BLADE CONCEPT (MBC) STRUCTURAL STOPPING POWER”, you list the three target priorities. However, target area 3 is the same paragraph as the one above.

    • Customer Service

      Hi Brian. You are correct and we are working to correct the conversion error. We are sorry for any inconvenience.
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  7. joe

    All well and good except that the “de-fanging” principles mentioned were historically applied with large bolo type knives, not small pocket knives. Small knives do not cut as deeply and effectively as large knives; even a cheap machete can hack at a limb with ease compared with a pocket folder. It comes down to momentum and reach, which is why small knives have historically been tools and not weapons. So what’s the answer? Carry something the size of a Bowie or be prepared to be disappointed by your knife’s performance (No, I don’t carry a Bowie).

  8. Peachy

    Very informative and articulate! Enjoyed reading, and actually flinching while my mind was visualizing. Thank you very much.

  9. Bob

    Well-done and interesting article, EXCEPT that you have repeated a paragraph and are missing a paragraph. In the last section, you mention that MBC has three target priorities: You mention 1) The inside of the wrist, 2) The biceps/triceps of the upper arm, and then you mention 2) again, without mentioning the third of the targets.

    • Customer Service

      Hi Bob. This has now been updated. Thank you for bringing this to our attention.

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  10. William Bell

    Very thoughtful article Michael. The fact that you can disable and escape using the techniques you describe would be much easier to defend in a court of law than a technique that would probably result in eventual death of the attacker. Not only would this be effective, but much more economical to defend from a legal standpoint. Efficiency and economy in one technique! I like that approach.