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What Causes a Knockout?

by Mark Jacobs
Excerpted from The Principles of Unarmed Combat

Starting at the top of the body, as was mentioned, the head is vulnerable to concussion, which has an automatically impairing effect. Though blows to any part of the head can potentially cause concussion, unconsciousness or even death, certain areas are much more likely to produce these effects than others. A great deal of misinformation has been given over the years regarding what are the prime areas of the head for causing a "knockout" due to confusion as to just what type of injuries produce a concussion within the brain.

Primarily, it is the acceleration or rapid movement of the head that produces concussive effects. Sometimes this is a result of the brain, which essentially fl oats freely inside a liquid atmosphere within the skull, banging into the inner wall of the skull; sometimes it is the result of sheering or other forces upon the brain itself. The two basic ways the brain is accelerated to cause these effects are through the application of translational force and rotational force. Translational force is any force that would snap the head straight back, straight forward or directly to the side. Rotational force would make the head rotate along its central vertical axis as if you were turning your head to look to the left or right. Translational force is generally produced by strikes that come straight in to the front or back of the head or straight strikes that come in directly from the side and land against the side of the head. Rotational force would typically be seen in more circular type blows or straight line strikes that land at an angle against the face. Most strikes that land against the head tend to produce a certain mixture of both translational and rotational forces.

This is important to understand simply because one needs to realize that the translational forces seen in many strikes to the head are often, by themselves, not enough to produce the type of head accelerations that cause concussions. However, rotational forces applied to the head, even if they do not produce extremely high accelerations, seem particularly effective in causing concussion, especially when combined with translational forces. Essentially what this means is that blows to the head which cause it to move the most are often the ones most likely to cause concussion.

The Chin as a Target

The point of the chin is frequently mentioned as being the best area to cause a knockout and certainly examples of its effectiveness abound in matches from boxing and other combat sports. Various reasons have been put forth for this target’s effectiveness including such fallacies as "the jaw bone presses against a nerve which causes unconsciousness". Although there is some medical speculation that blows to the point of the chin can affect the submental nerve which runs directly under the chin, there is little hard evidence that this contributes signifi cantly to a knockout blow.

However, the point of the chin probably is one of the best, if not the best, areas to cause a concussion upon an opponent. But the reason is most likely one of simple physics. The chin is a point of leverage. On most people it is the furthest spot from the head’s center of gravity. This means that when it’s struck, it will tend to cause more movement to the head than any other location would, which means more translational and/or rotational force is applied to the brain making concussion more likely. It is often said that fighters with long, thin jaws are more susceptible to knockouts and those with more of a square jaw are better able to withstand blows to the chin. The physics we’ve been discussing would tend to give some credence to this theory since a longer jaw would make a person’s chin even more of a leverage point.

Besides containing sufficient power, the angle and type of blow that lands on the chin is important when looking to cause concussion. Hand strikes are probably the best weapons to go about striking at the chin, either punching with a closed fist or sometimes striking with the “heel” or bottom portion of the open palm. Either can prove effective. With a bare hand, the closed fist is believed to be somewhat more effective since the power is focused over a smaller and less padded area. But the heel of the open palm is sometimes seen as a better alternative when striking the head barehanded due to the possibility of damaging the knuckles against the hard bones of the skull with a closed fist. However, the chin is not quite as solid a target as the skull and much of the surrounding facial tissue is also far softer than the skull so even if the blow is off target, there is less chance of damaging a closed fist when hitting to the chin.

Any type of kick would be much more difficult to land accurately against the point of the chin. It is simply harder to be accurate throwing a strike with the foot than with the hand and even a front kick that comes straight in to the chin, besides taking far longer, will have more difficulty landing accurately on a relatively small area. However, these drawbacks are sometimes mitigated by the inherent surprise factor of throwing such a high kick.

Elbow strikes, though possible, tend to be used at close quarters and most of these would probably land against the side of the opponent’s head at this range. Elbow strikes that rise straight upward, in an uppercut type fashion, are theoretically possible though the distancing between you and the opponent would have to be almost perfect. If you are too close, the elbow would brush against the front of the opponent’s chest, too far and the elbow would pass harmlessly in front of his chin.

It would therefore seem hand strikes are the best option when hitting to the chin.

As for the specific angle you’ll attempt to strike on, a blow that comes in perfectly straight and hits an opponent directly in the center of the chin would produce a fair amount of translational force snapping the opponent’s head straight back. But unless you’re someone who possesses significant punching power or you catch the opponent when he’s moving into you, such a pure translational blow may not be enough to produce a concussive effect if you haven’t already worn the opponent down with many other blows. Throwing a perfectly straight punch to the center of the opponent’s chin that hits on a slight downward angle would likely produce even less effect. Uppercut punches that come in directly underneath the center of the opponent’s chin, although they possess less power than normal straight line punches since you can’t place as much body weight behind them, will snap the head back significantly. The other factor an uppercut has to its advantage is the fact that by rising straight up from underneath the chin, usually right between the opponent’s defending arms, it seems to be almost naturally targeted toward the point of the chin. However, it still takes significant punching power to cause concussion with a single uppercut strike. Keep in mind, although we are talking primarily about the effect of single strikes, blows can be delivered together in combination which will make them somewhat more successful in producing concussive effects. This may be particularly true of an uppercut blow if you use it to lift an opponent’s chin upwards, then strike it with a follow up punch like a hook when it’s in a more vulnerable position.

Additionally, the uppercut can be very effective against an opponent whose head is already tilted back slightly making it more difficult for him to see it coming. It is a truism in boxing and other combat sports that the blows which knock you out are most often the ones you never see. This is because when you see a blow coming, you will naturally tense up to brace yourself against it. This tensing, primarily of the neck muscles, can lessen the movement of the head, thus lessening the chance of concussion. But when you don’t see a strike coming, you won’t tense up to protect yourself and the blow will probably move your head to a greater degree.

Hand strikes that land against the chin at an angle may be the most effective blows for causing a concussion because of the extreme amount of rotational force they can generate along with their translational forces. These strikes can be either straight line blows that land slightly toward the left or right sides of the chin or hooking type blows.

The above article is copyrighted by the author. All rights reserved.

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