The Science of Knockout Power

In my last post, I talked about knockout power and addressed the common (mis)conception of if you are born with it or if you can develop it.

I feel that I’ve made a strong enough case so that I don’t ever have to answer that question again.

The bottom line is that whatever you’re born with, you’re born with. The rest you make up through learning, applying, then modifying to continue making gains. Just like everything else in life.

For example – me being a good husband. It’s a constant cycle of me learning what I’m doing wrong (scolding), trying a new technique (I hope this will work!), then observing the results (scolding or smiles?). I’m sure many of you have similar experiences. Oh and 1 piece of advice that I can give after almost 1 year of marriage – the woman is never wrong. Even if through bulleproof logic and reasoning you think it to be so. If you want to be happily married, the sooner you accept this fact the happier you will be.

In the Punching Power – Born or Made? video, I mentioned that I was going to share some advanced techniques with you to maximize your KO power.

Well, I figured this would be best shared in both a video and article, which you have before you. I know, I know, I said I was burnt out with the writing and all, and I still am, but as I did research for this topic, it fired me up and I want to convey this in the best way possible because I’ve got some really advanced and powerful concepts to share with you, so here we are.

Now, to get the most out of this article requires your focus and concentration, so turn off your cell phone, shut down your instant messenger, close other browser windows, put the Do Not Disturb sign on your office door, grab a glass of water or green tea, take a deep breath, and let's get into the SCIENCE of knockout power so you can turn your hands (or feet) into the lethal weapons that you've always dreamed about...

The title of this article is “The Science of Knockout Power“. So I’m going to do my best to show you the science behind what creates KO power, not just myth, legend, or “because so and so said so”.

First, What Causes a Knockout?

knockout powerMost often, it’s due to your brain banging into your skull. Your brain is basically floating inside your skull in fluid. When you hit your opponent hard, their head rapidly accelerates in one direction. Because the brain is suspended, it takes a second to catch up and the skull can come in contact with it, causing damage. Or, when your head snaps back, the brain might bang into the skull then. Either way, it’s due to this impact and the brain “short-circuits” and you lights-out!

Man, all this writing about this stuff is making me second guess my desire to box… Anyhoo…

A Punching Power Myth… Debunked

One thing I’ve got to do is break down one of the big myths related to punching power: the myth that states that it is the result of snapping your fist back as quickly as possible to maximize the “impulse”.

This is one that I believed and I’ve actually written and talked about in the past. I no longer believe this to be the truth. There are 2 reasons: 1 scientific and 1 observation from real-world results.

At the speed at which an effective punch travels, it will cause your opponent’s head to “bounce” off of your fist. No matter how fast you pull your fist back after making contact with your opponent, this bounce will be faster.

In fact, trying to pull back quickly will only lessen the chance of KO’ing your opponent by decreasing the speed at which you hit your opponent with. More on this later…

knockout powerNow this bounce is not as perceptible as a tennis ball bouncing off a wall… It will happen within the structures of your gloves, wraps, skin, soft tissue like fascia and muscles, and finally your bones where each component compress then expand away from each other.

But just because you can’t see it, doesn’t mean it’s not there. This bounce is an inherent property of all of the structures involved in landing a punch on your opponents head.

Oh wait, you can see it – check the pic out and you can see the guys face deforming and bouncing away from the fist – the mouth and jaw are farther away from the fist relative to his head. This is the “bounce” I’m talking about.

Now, to debunk this myth with real-world results, let’s analyze some knockouts themselves. The video below is a collection of one punch KOs from boxing. I chose boxing because it is a heck of a lot harder to get a one punch KO in boxing compared to MMA, due to the gloves. This video also shows you the KOs in slow-mo where you can see exactly what’s happening. As you watch the video, try and look for the punch and see if the fighter is ripping their punch back quickly to generate “snap”:

Do you see the snap back?

No, you don’t. That’s because in each and every knockout, it never happened. If the “snap back for power” myth were true, at least one of these KO’s would’ve shown it.

As you can see from the video above, each of the KO punches entails the fighter punching through their opponent’s head, which is one of the 5 keys to KO power I talk about later. Why does this matter?

This is for no other reason than to hit with maximal velocity. Any effort to draw the punch back quickly will minimize this velocity and no KO would’ve occurred.

The Scientific Formula for Knockout Power

When it comes to science, I believe the most important equation related to KO power is this:

Kinetic Energy (KE) = 1/2 mass x velocity^2

KE is the amount of energy in your fist, which you want to maximize at the point of contact. To maximize the KE:

1. Maximize the amount of weight behind the punch
2. More importantly maximize the VELOCITY of your fist

I say that velocity is more important because in the equation, it is squared. To all those lacking math skills or the Chinese math brain that I am so lucky to have been born with, when you square something, you multiply it by itself.

So if velocity is 3, plug it into this equation and you get 3^2 = 3×3 = 9.

If velocity is 4, you get 4^2 = 4×4 = 16.

Velocity is exponential, whereas mass is linear.

So back to the “snap back” myth – when you are trying to pull your fist back, you will be lowering the velocity with which you hit your opponent. It is simply not physiologically possible to instantly reverse the direction of your fist at the instant of impact. And as I said before, the bounce between head and fist renders this irrelevant anyway.

So now that we’ve busted one of the bigger myths about punching power, and one of my past erroneous ways of thinking (sorry about that, but I’m always learning, too), let’s continue…

Because velocity is squared in the KE equation, it is more important to getting knockouts, and is the factor we can influence more.

But getting your weight behind a punch can still play a huge role, just ask anyone who fought Mike Tyson:

See how in most of those KO’s, he is moving forwards and throws his whole shoulder into the punch? This is only possible if you get close to your opponent, which he had a great ability to do because of his head movement (and fearlessness). I’m going to have to save going into depth about this topic for another article… Let me know if you want see this or not.

Back to velocity –

Like I’ve already said, the 2 over-arching principles are to maximize the weight behind the punch, but more importantly, maximize the velocity of the punch.

To maximize the velocity of your punch, I’ve come up with 5 keys, all based on science, that will increase the power of your punches.


The 5 Keys To Maximizing Knockout Power

Key #1. Circular Punches are the Most Powerful

In my research for this article, I found a study titled “Concussion in professional football: comparison with boxing head impacts – Part 10” published in the journal Neurosurgery in 2005 measured the impact forces of 4 punches: hook to temple, straight to forehead, straight to jaw, uppercut to jaw.

The results showed that the hook to the temple was the most powerful punch, resulted in the highest acceleration of the head, and has the highest “head injury criterion” score based on the data collected. Here’s a table from the study showing the various forces:

knockout power

Click to Enlarge

Note that the uppercut scored as the “weakest” punch – I believe this is because with an uppercut, you can’t take advantage of some of the other keys to KO power mentioned below as well as hooks or overhands (#3, #4)

We also have real-world verification from the knockouts in the videos above as well as most one punch KO videos you’ll watch in boxing or MMA, which are all usually a result of circular punches, most common being hooks and overhands.


Key #2. Punch Through Your Opponent’s Head

As I mentioned earlier, if you want to get a big KO, don’t focus on trying to bring your fist back to guard. While this is great for defense, it won’t help you knock someone out because you’ll decelerate too early and lower the velocity of your fist.

Instead, punch through your opponent.

Think about baseball – when you swing for a homerun, do you stop the bat and try to reverse once you make contact? No way, Jose. You swing right through with all your might.

Circular punches, because of the path they travel and the fact you don’t try to reverse the path of your fist to go back to your defensive stance, naturally help you punch through your opponent and hit with max velocity.

But even with straight punches you can do this by aiming at the middle of their brain instead of their face. Check it out in action in this clip from Junior Dos Santos’ knockdown of Frank Mir:

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Watching the video, you may even notice that Mir’s head bounces away from Junior’s fist before he retracts his fist, even though he retracts it very quickly.


Key #3. Use Summation of Forces (SoF)

Just punching with your arm, like in a jab, is always going to be less powerful than punching with your whole body by rotating through it, like with a hook.

I used to believe that you wanted to drive through the ground for this, too. After my research, now I think that driving through the ground can help you increase the weight behind your punch, like pushing off to walk forward and punch, but it won’t add velocity because of the direction of the force vector.

When you walk forward, you are directing force forwards (in the sagittal plane), but to use the summation of forces, it all happens in the transverse plane and that can only happen at the hips/core, not the ankle/knee.

So starting the punch through your hips/core is the key to summating the forces for max punch velocity.

However, you’ve still got to be grounded for balance and to be able to use your hips/core muscles, but you’re just not starting force generation from the ground.

With this line of thinking, the pivot of your foot when you throw a rear cross or hook is more a SIDE EFFECT that helps to avoid torquing your knee and helps you rotate through a great range of motion at the hips/core as opposed to adding power to the punch.

Now, the key to Summation of Forces is timing – you’ve got to start the rotation at your hip, then core, then shoulder and finally it ends through your fist. Here’s a good exercise to train your Summation of Forces.

But the timing is very precise, and if you get it, you take advantage of the next key, which can really increase your punching power…


Key #4. Use the Stretch Shortening Cycle (SSC) 

I’ve talked about this a bunch in other videos and articles on my blog, probably most recently in the new kettlebell exercise I shared and also in my BIOMECH BREAKDOWN of Barboza’s spinning kick KO.

If you’re a long-time follower of mine, I hope this concept has sunk in by now!

Basically, the SSC occurs when you quickly stretch a muscle/tendon/fascia complex (the quicker the better) then as quickly as possible, you contract that muscle. This adds a whole bunch of elastic energy to your punch and increases the power of your punch.

Naturally, this occurs in combination punches, because the rotation of one punch winds you up for the next punch.

But you can also do this for single punches as shown by the great Anderson Silva in fight vs. Yushin Okami:

[jwplayer config=”640×360 controls” mediaid=”6107″]

I slowed it down so you can see that right before he delivers the KO blow, he quickly rotates to the right to load the SSC for his right hook. This is an advanced skill and is one of the reasons why Silva is such a great knockout artist. However, let’s give credit where credit is due – I’m sure he learned it from Steven Seagal.


Key #5. Be as Relaxed as Possible

To finish this article off, we must go back to, in my opinion, the greatest fighter in MMA history – Anderson Silva.

Remember his KO vs. Forrest Griffin?

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Notice how Silva is holding his arms down before he throws the punch – this maximizes the relaxation in his shoulders, where the punch originated, which allows him to generate max velocity. He then keeps relaxed in his arms and only contracts what needs to be contracted to throw his punch.

If you’re tense, it decreases your potential velocity in 2 ways:

  1. You’ve got to overcome the force of the muscles that are tense. This is how most beginners punch – they are very stiff.
  2. You can’t stretch the muscle to use the SSC, since it’s impossible to stretch a contracted muscle.

True mastery, not just with punching, but most athletic endeavours, requires you to learn how to maximally fire the muscles that you need to do the job, while relaxing the opposing muscles.

This KO is one of the best I’ve seen in my life because Silva goes from chillin’ out, walking backwards, to throwing his shoulder into it (to get some SoF and SSC) and throws a circular punch through the chin of the Forrest…

Thus, Silva takes advantage of ALL 5 KEYS, which is why this KO was so remarkable.

It’s also a great example showing that you don’t necessarily need a lot of weight behind your punch, if you have enough velocity.

To generate maximal velocity, use all of these keys and you’ll soon be knocking mofoz out!

OK, I’m tired. That was a BEAST of an article. I don’t have anymore energy to write a witty, engaging or useful conclusion.

Holy shit I’ve been writing this for 5+ hours right now, not including the reading/research I did before. I’m frickin’ tired. That’s it, I’m out.


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Lawrenceshbbc xkkjxnJohnsee this hereyanlizasker Recent comment authors
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An uppercut to the chin may possibly gain effectiveness by snapping the head back, or thru the glass jaw effect.

Experiments with concussion forces seem to show that a rotational stress to the brain may have significant impacts, such as when a car is hit broadside and spins, or a hook to the jaw causes head spin.

There may be additional factors that enter into the KO equation.

shbbc xkkjxn
shbbc xkkjxn

ok i do test be myself with 2 object one 600 grams second 300 gramms which i let go from specifed hight on arms on which on another sidde was also some object with specifed mass this test literraly measured impulse or average force which work on this object on end on this arms first i drop this heavie object form hight 0,25 meter object on end on arms jump on 0,2 meter around 0,18-0,20 m more or less ( i m not do very precise measurement ) than im drop lighter object 300 gram from 1 metres hight that gives 4,5 m/s this heavier have 2,25 m/s around anyway 2 Times faster but 2 Times lighter object push this object on end on arms on 0,8 meter hight ,damn that mean reallly speed is more important in impact force and impulse than mass ,coooll stufff;) so ok now im… Read more »

shbbc xkkjxn
shbbc xkkjxn

wery good article except 2 factor in me opinion kinetic energy im not sure that this is most importet formula for k.o. power i think more important formula is f=mxa or momentum =speedxmass in kinetic energy speed is 2 Times more important than mass however anybody do test if 2 Times more speed give 4 Times more impact force? on for egzample head crash test dummy ? or its the same important as wmass so 2 Time mass 2 Times force 2 Times speed 2 Times force ? i never seen such test on crash test dummy for egzample ,and second be as relaxed at posiible its bullsheet i hear this once looks at francoius nganou or dan hendorson they are known for they k.o. punch both are very rigid rigid give very good transfer be kinetic chain punch mass at impact and penetrative charaacteristic ,so i want to see… Read more »


For those that may find some things confusing, look up a few things & then read the article again. Look up force, inertia, law of motion, the basic laws of physics should cover pretty much everything. When a jaw is punched with enough force to cause the head to quickly twist & then twist back, neurotransmitters in the brain cause it to briefly shut down, kind of like hitting a reset button. This is one way a KO happens. The other is when the side of the head is stuck with enough force to cause the brain to crash against the skull. This way may take more than one strike. Neurotransmitters contain potassium (& a few other things). When the brain is hit (concussed) potassium is released & replaced with calcium. The heart pumps & repairs this exchange. When the heart can’t keep up with the rate of the potassium… Read more »

see this here

You really make it appear so easy along with your presentation but I to find this topic to be really one thing which I think I’d never understand.
It seems too complex and extremely huge for me. I’m having a look ahead to
your subsequent put up, I’ll try to get the hang of it!


In Jeet Kune Do, we are taught to end the strike within 1-6 inches through the opponent, with a snap. This way we use both follow through and snap, and get the best of both worlds. Why do you have to pick one over the other.


I do not agree with this completely. first of all, yes when hitting to the head snappy punches do knockout easier.. since the head is vibrating more. secondly, i must also say that snappy punches do not have the same effect to the body, since you must dig in and it is not like the head… thirdly, i do agree where u said u gotta be relaxed, since someone not relaxed will not be a good fighter anyway… and my conclusion is that snappy punches are faster, and i believe speed=power when it is a hit to a head. why? because then as u pull back you will have more snap and what causes a knockout is when the brain hits the skull, therefore do you want to push the head? or snap the head? thank you, nice article to discuss though.


You just dumbed down a perfectly explained article. No disrespect meant at all. But, to your first point, snappy punches do not cause KO’s easier because the vibrations. The vibrations are caused from the punch. The follow through couldn’t have been explained any better. Using the baseball bat example: a ball travels farther when the bat swings through it, as opposed to stopping the bat at the point of contact. There’s more velocity created by swing through an object, period. Its scientific fact, not opinion. Second, the article discusses head contact, not body contact. A body KO is caused by an entirely different thing, however the science behind this punch isn’t dependant on what is being punched. Your third “point” agrees with the article, so it should be your first point you agree on, thus leaving only two points you disagree with. However, “someone not relaxed will not be a… Read more »


Can you explain why a bare fist punch will knockout an opponent faster than an mma glove or a boxing glove. I have a buddy who just wont back down on his version of why the boxing glove is better than the othe two. I would love to shut him up once and for all!!!



Inertia.. A glove displaces the point of impact over a larger area. It “spreads out” the impact. If you’re in quick sand, you lay flat to spread out your weight. A glove buffers the impact as opposed to a solid fist impacting on a centralized area, concentrating the mass & velocity in a dense foward motion. If you shoot the exact same weight of bird shot into a board as a slug, the slug will go through, whereas the bird shot will bounce off. Even tho both weigh the same & travel at the same speed, the bird shot is spread out. A glove displaces the force at the point of impact, spreading it out across several inches as opposed to a solid fist impacting in just a few inches. A glove also creates drag, & weighs down your hand when traveling through the air, lowering velocity. Velocity = key… Read more »


Dumb article, Eric dosnt really understand whats going on but tries to explain it with valid science, but still gets crucial points wrong himself.

I think hes more about taking your money and posing as an expert rather than giving value or becoming a real expert.

Eric Wong should be renamed Eric Wrong.

Eric you can understand some scientific concepts but thats as far as it goes, anything that comes from you is wrong, so stick to parroting the science/your education, and not adding your own “theories”


Great article.

Manny Driggs
Manny Driggs

Although I see were you are coming from regarding the importnace of the hips and the core in generating power for the punch, the front foot stepping forward and the rear foot’s toes driving down into the ground simultaneously as the rear heel lifting upwards can generate up to 25% of the force in a right cross. I still feel that footwork plays a very important role as far as positioning oneself into the optimal angle to strike and to set up for the next punch. The sequence of the front foot stepping and the rear foot driving is extremely important. If the lead foot lands before the right hand strikes- you wll have limited your power substantially. Its helpful to think of the body as a big cork screw when punching. It starts from the ground and moves up your body from that point. Thank you for writing this… Read more »

Laura Te Aho White
Laura Te Aho White

The only punch that should ‘snap’ back in Boxing is the jab.

Santiago Sanchez
Santiago Sanchez

UMM IS PUNCHING POWER BORN OR MADE??? haha just joking great article

Johnny G.
Johnny G.

very nicely done sir. I sincerely hope your message get through to your reader’s.



Another thing that will add to the knock out is what I call hidden distance.

Notice when Anderson hits forest with his fist, it’s low and by his hip, it’s about a good three to four feet away from Forest’s face.

Which is more than enough to generate velocity in the punch, Anderson could have wound up and thrown the punch but he didn’t need to as he was already loaded up to throw it from his hip.

Johnny G.
Johnny G.

that a boy Dan.



great article man!! i have knocked out several people in my life and have tried to teach my students about kinetic energy and how important it is when fighting(without fully understanding it )and you have got it all right here. I will be sending this out to all my strikers. Thanks again

Andrew Thomas
Andrew Thomas

First, I love your website and all of the info you’re sharing with us. I’ve got a question about all this though. To maximize the five keys, particularly punching through the target, does that mean that ‘snapping’ the punch can’t be done?


What I’m talking about is the concept of snapping the punch, in terms of the old Karate way of thinking, is not going to help with your punching power.

You definitely still want to pull straight punches back as quickly as possible, but know that doing so is not increasing power and may actually decrease it, if you do so too early and it results in deceleration of your fist before impact.

I read a great article here that talks about this more:

I suggest everyone read that article.

Andrew Thomas
Andrew Thomas

Thanks for the clarification Eric. I wish you were my teacher!

Santiago Sanchez
Santiago Sanchez

Devon Alexanders an example of someone who when trying to create a snapping punch rips their punch back too quickly and lessens the chance of a ko


Great article, thank you. This definitely help me out a lot in my training. Again, thank you!!


Good article Eric but are knockouts all about power? If so, then how does a weaker person who can’t generate much power still knockout a much larger person? It happens. Also many of these professional fighters are “used” to being hit on the head by very powerful hits but still don’t fall over. Yet the same person can be hit by ‘a nice shot’ and drop like a fly. When Silva took out Griffin the hit didn’t look all that ‘powerful’, compared with some earlier shots in the fight. He was actually retreating, with only one foot on the floor, leaning backwards (bad SoF), used a straight shot rather than a hook, and he hadn’t wound up with a previous strike so as to maximise the SSC. But it was a nice shot, on target. What about looking at the location of the hit and the direction of that hit?… Read more »


Good point DJ and I have definitely thought about this. I talked about some of the other components in my Punching Power – Born or Made? video…

Other things like accuracy, being able to setup your punch, FEARLESSNESS, etc all play a role for sure.

In this post, all I’m talking about is maximizing power.


There are many more factors that dictate the result of a punch being a KO. Many ppl commenting are missing the point of the article. Yes timing has a bit to do with being able to KO somebody. If a person braces their self & turns their head at the moment of impact, causing the punch to be deflected, of coarse it may not result in a KO. Yes pivoting your rear foot & pushing off of it is PART of the “25%” potential increase of “power”. But the actual act of the foot coming off the ground is a result of the hips turning & thrusting your shoulder arm & fist in a forward direction. Newton’s law of motion should be understood. Your feet apply a downward force. The ground doesn’t give so that force is directed opposite the ground (up through the body & forward). Many of the… Read more »


Oh and WRT Silva/Griffin, he did use SoF, as it was using torso rotation and shoulder power, and it was a circular shot, it wasn’t a hook, but it started low, then went up and then back down, so it was like a hook/jab type shot, or a “downcut” if you will.


Love it! Good job digging out the research on the concussive effect of the different strikes to the head. Excellent analysis and integration of knowledge.




Great article! Makes so much sense. I also appreciate the honesty and admitting the mistakes, it shows you are deeply true with us and makes you a great teacher!


Isn’t that “stretch shortening cycle” not strength?


Yeah – good call on the typo Troy. Told you I was tired! 🙂


Great article really enjoyed it. Going to take in those principles and apply them to my boxing. Funny enough the last time I knocked someone down it was a left hook off a right cross, so had the turning bit without thinking about it and was inter club sparring so was relaxed not tense like a bout!! Will defo try to apply the medicine ball twist as well to get that twist velocity nice!!!


Good stuff. When sparring you definitely don’t want to think about it – so that is good on you also. But in training, that’s when you put the mind to work to develop these automatic KO patterns!