As a child I watched (with my father) a boxing match which lasted 12 rounds. At the end neither fighter resembled his previous pretty self, but nobody got knocked out either.

I just watched Terra Nova where the main character layed out a kidnapper in one punch. I've seen this a lot in movies. In the movies is so easy to lay someone out by landing a fairly decent blow to the head.

So I have to ask: Are movies giving an over-simplistic idea of how easy it is to knock someone out?

Or as the title asks:

Is it really as easy to knock someone out in real life as in the movies?

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    BTW I don't really get the boxing match analogy. Boxers are obviously harder to knock out than ordinary people. It's why they're in this profession. ;)
    – Walt
    Commented Jun 19, 2015 at 8:09
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    I just want to know if its possible to one-shot people and put them out cold in RL like in basically every single movie. The idea seems convenient to the sitaution: In some scenes the hero/villain can have a 10minute bloody fight, but leading up to the ultimate fight the hero knocks out 10 or 11 bad guys by pushing a special button on their head that puts them to sleep.
    – 1Up
    Commented Jun 19, 2015 at 8:32
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    On a different but related note: it's not normal for people who are knocked unconscious (easily or otherwise) to stay that way for minute or hours. If you get hit in the head and don't wake up within seconds, odds are you've got serious brain damage.
    – KutuluMike
    Commented Jun 19, 2015 at 14:33
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    Something to note about boxing matches: Boxers' gloves are padded to soften blows and produce prolonged fights. Longer fights are more entertaining and more people will attend matches that last longer than a minute or two. I think we can all agree that these softer blows are less likely to knock somebody out. Commented Jun 19, 2015 at 18:46
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    This question would have gotten even better answers on the new health.stackexchange.com because it is a question about real-life medicine, not movie medicine.
    – Philipp
    Commented Jun 20, 2015 at 12:08

10 Answers 10


Disclaimer: Violence is stupid and dangerous. A blow to the skull is often fatal.

I wouldn't say it's easy, but there are several sweet spots on the skull that, when hit with sufficient force, is almost guaranteed to cause unconsciousness.

I would suggest the upper part of the jaw bone or the temple. Both places are connected to the brain stem through nerves and/or arteries. A punch here will cause the force to reach your brain and shut you down.

I also believe that it's an important factor whether you expect the punch or it lands like a lightning from a blue sky. The latter are by far the worst. You'll almost certainly wake up surrounded by panicked individuals with a severely swollen head and no clue as to what happened ... then you throw up.

Found this on Quora:

A bunch of studies of head injuries in primates were done at U Penn some years ago. Bottom line: it took 3 times less energy to knock an individual out with a ROTATIONAL blow (e.g. roundhouse punch) than with a TRANSLATIONAL strike (e.g. a jab).

There are 2 main mechanisms:

1) Cerebrospinal fluid (CSF) can cushion a linear blow, but not a rotational one (the CSF and brain spin side by side in a rotational movement)

2) the upper brainstem and higher brain can twist on each other because of their size, shape and relative positions (and the arteries that supply them can also twist), kind of like an apple and its stem, causing loss of function precisely where "consciousness" resides in the brain (the reticular activating system)

The studies mentioned by the Quora poster might be any of the many studies that came out of the Head Injury Laboratory at the University of Pennsylvania, but is most likely referring (primarily) to "Physical model simulations of brain injury in the primate", by Margulies SS, Thibault LE, and Gennarelli TA (published in the Journal of Biomechanics in 1990).

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    I would suggest the upper part of the jaw bone or the temple. I would suggest not doing something like that at all if you value your freedom; knocking someone out without also causing death or serious, permanent injury is a lot harder than movies make it look! Commented Jun 19, 2015 at 15:51
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    Reading "studies of head injuries in primates" makes me visualize a bunch of scientists punching monkeys and taking notes.
    – Lindsey D
    Commented Jun 19, 2015 at 18:08
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    @LindseyD Related to this video (the onion so it is a parody) youtube.com/watch?v=uyHYw8nDx9A
    – invalid_id
    Commented Jun 19, 2015 at 19:29
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    I know you're quoting this and that you didn't write it yourself but 3 times less energy reminds me of what my father says: if the initial energy is 100 Kj then three times less than that is 100 Kj - 300 Kj = -200 Kj, which is obviously nonsensical. What they really mean is the less punchy(!) one third of the energy.
    – CJ Dennis
    Commented Jun 21, 2015 at 11:40
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    The Quora post being quoted confuses rotational acceleration of the head with rotational acceleration of the blow. Every good boxer knows that you don't want to throw a "roundhouse"/swing. You want a tight, "translational" punch. Note even a properly done hook is a translational blow, it's just that it hits from the side and the arm is bent, so to the layman it looks like a swing. Boxers knock people out with a straight right. It's really about the angle of attack, does it hit to the side of jaw or not? Commented Jun 22, 2015 at 4:44

I'm gonna have to go against the grain here. As someone who has trained boxing for years, no, it's not even close. It is extremely hard to do in real life, and people don't stay down more than a few seconds. In my entire boxing "career", I've taken thousands of blows, and I've never lost consciousness. I've hit other people thousands of times, and only like twice have people fallen down, and they've gotten up almost immediately.

What you see in the ring is pretty indicative. On average, it takes something like 200 punches in the head, from the best professional punchers in the world, to bring down an opponent. Those 1 hit knockouts you see in YouTube videos and highlight reels are extremely anomalous, they happen once in a million punches. Or more often, they happen to drunk teenagers, already staggering, who are fucking with professional (if retired) boxers like in the videos linked in some of the answers here.

And if you do actually hit someone so hard that you knock them out for more than a few minutes, they are almost guaranteed to have a concussion and need to see a doctor immediately. You don't get to knock someone out for 2 hours just to incapacitate them. Head trauma isn't that convenient in the real world.


Easy vs. Possible.

Is it possible. Yes. Even with relatively minimal training it is a fairly simple matter to teach someone to transfer enough energy through a strike to cause unconsciousness.

Is it easy? No. Transferring that much energy requires, among other things, striking through the target. If you watch beginning karate students attempting to break boards you will see many of them take several attempts, even though they are punching with all of their strength and with relatively good technique. The reason it takes them so many attempts is that they are focusing the end of their blow on the front side, rather than the back side, of the target. So while they punch with power, the power doesn't transfer to the board in a way that causes it to break.

That doesn't mean it doesn't happen. It does. But it's not a regular occurrence.

Now, where it gets tricky is this: the force needed to knock someone unconscious is very similar to the force required to kill them. It has more to do with the location and direction of the force applied to the brain tissue.

What is almost always false about movies (regardless of if they show a one-punch knockout or not) is the lingering effects of traumatic brain injury.

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    By "the power doesn't transfer to the board in a way that causes it to break" you mean "they don't impact the board with the same power because they're slowing themselves down to meet their target position". The board couldn't care less about what the person is aiming for.
    – Rex Kerr
    Commented Jun 21, 2015 at 3:30

It is possible knock someone out with one punch. Searching on Youtube for "One punch knockout" gives you many results (also in boxing). An example. (warning, contains violence and some may be fake.)

The spot where someone is hit is important though, but it is definitely possible; whether it is easy depends on how well the person hitting and the person being hit know what to do in fights.

Furthermore, boxers of course try to protect their heads from getting knocked out, yet still they also get a knock-out every once in while.

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    It might be worth pointing out that there is no safe way to knock someone out without causing serious damage and endangering their life (in fact, unconsciousness by itself can be life-threatening when the person is not placed in a recovery position).
    – Philipp
    Commented Jun 20, 2015 at 12:06


Source: Personal experience.

A relative was extremely irate with myself, and had been throwing punches at me for about 20 minutes. I had finally had enough and jabbed his bottom jaw towards the front. (If you feel on your own jaw, and you are not too overweight you should feel an area somewhat less padded, and sensitive than the rest.) He dropped, and was motionless for about 20 seconds. I have seen others knocked out from seemingly mild impacts while play fighting at school, or sport incidents. I have never trained any form of hand to hand combat, I am slightly stronger than average, but not by much.

Caveat: If someone was knocked out for an extended period, this would fall into the category of "not very good things to happen".

  • You should learn how to do a Rear Naked Choke. That 20 minutes would have lasted no more than 20 seconds and been safer for both parties.
    – Mazura
    Commented Jun 20, 2015 at 19:07

There are several issues here in comparing real life to movies. A trained person knows how and where to strike for maximum damage and this person can definitely knock someone out with one blow. It may seem simple but it takes a lot of practice to develop an accurate punch. The average person might know to aim for the temple but not strike there for a many reasons (among them is that the person he's fighting is throwing a punch, moving, doing something to protect himself).

Professional boxers do get knocked out with one punch (see Marquez-Pacquiao) but most of the time they do a very good job of protecting themselves. It may look to some people that they're just a bunch of thugs throwing punches but they are marvelously trained and prepared athletes.

So back to the question: who is throwing the punch? A trained, experienced soldier or fighter? Who is his target? Just another guy without training? Is the professional in good shape weighing 180 pounds or more? Then yes one punch knockouts can and do happen.


Is it possible? Yes. Have I seen it? Yes.

There is one huge bit of information missing from all of these answers; boxers use padded gloves. Now, they have tape underneath to add impact to the punch, but the gloves are padded and a well-trained boxer knows how to protect himself and reduce the impact of the blow.

A street fight is bare-knuckles, and that's gonna do a lot more damage. particularly if it hits a pressure point or a point more vulnerable on impact.

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    Padding does nothing to stop knockouts, it only prevents cuts and fractures by spreading the damage over larger surface area of skin. The knockout comes from your brain hitting the inside of the scull when the energy of the punch is transferred to your head, and padding does absolutely nothing to stop that. Matter of fact, heavier gloves (with more padding) can be even more dangerous. If you take a look at MMA, you'll see that knockouts don't happen with any higher frequency with thinner gloves.
    – Davor
    Commented Jun 21, 2015 at 14:53

Boxing is even less accurate representation of real life than movies. In fact, everything possible is done to prolong the match. Boxers are both trained and equipped to stay conscious as long as possible. Because sport is a show, and longer shows can be priced higher.

On the other hand, movies are like playing roulete with remote-controlled dices. For the sake of the story, things which are merely possible or probable in the real life for fictional characters work with 100% dependability.

Bottom line: Is it possible to do "movie knockout" some time on some guy? - Absolutely yes.

Is it possible to do "movie knockout" every time on every guy? - Hell no.


Yes it is and there are multiple evidence of that on youtube, like these:


There are two things worth mentioning though: 1. It takes a lot of practice to be able to do that. 2. It is hard to control the damage that you are causing by these knock outs. People die from getting punched in the skull/falling/etc.

  • Both links are dead, please consider replacing them.
    – Jenayah
    Commented Sep 12, 2019 at 15:30

Vulcan neck pinch does not work. Hitting someone on the very top of their head doesn't work-though with enough force can cause concussions. Same with the back of the head (it's a little tougher too). Knocking someone out is simply trying to get their brain to rattle around in the fluid it's in. Easiest way is a punch thrown in a way that would hit a target on the chin. The force required must be superior than the target resisting it. Sucker punches are especially effective because they turn the head when the target doesn't see it-so they don't brace against it. Boxers have trouble doing it because the target should be tucking their chin.

To do it as easy as in a movie, a righty can use a left uppercut (upward fist strike) to hit a target in the head to force the chin up, followed by a fast right hook (punch sent from your right side thru target's chin to your left side). This does work and is very fast (less than 2 seconds to put someone down) if you're accurate and have mediocre force.

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