The Physics Behind Bruce Lee’s One-Inch Punch! (Because Science w/ Kyle Hill)


– Today’s episode of Because Science
is sponsored by Birth of the the Dragon.
Birth of the Dragon hits
theaters everywhere August 25th.
(karate yell)
What is the most-famous martial arts move?
In terms of sheer popularity, I’d argue
that it is the one-inch punch.
And I think it’s so popular
because it looks impossible.
Like it’s generating too much force
for how much space it has to do so.
But it’s not impossible.
It’s not magic.
It’s not chi.
It’s physics.
(karate yell)
The story goes that
the West was introduced
to the one-inch punch
through a demonstration
by the dragon himself at
the Long Beach International
Karate Championships in
1964 and as you can see,
dramatized in the upcoming
movie Birth of the Dragon,
it hits confusingly hard.
Here’s one slowed down.
It’s a legitimately wow
move, so how does it work?
The martial artist was
obviously in fantastic shape.
But with only one inch to work with,
it looks like all that power we see
in the demonstrations has
to come from somewhere other
than just arm muscles, and it does.
Martial artists call this kinetic linking,
but a physicist looking
at the one-inch punch
would call it kinematic chains.
Wait, wait.
That is three inches.
Should we tell someone?
A kinematic chain is an
assembly of rigid bodies
connected by joints in some way.
Now think of the entire human body
as an assembly of kinematic chains.
What the dragon did and what
all good martial artists
do is punch with more
than just their fist.
It starts at the ground,
translating motion
in feet and thighs into
the torso, into the arms
and then all the way to the
end point, the final punch.
In this way, they punch
with more kinetic energy
than the fist would have otherwise.
How much kinetic energy
a fist has upon impact
will determine the impact force.
Energy and force are
often used interchangeably
when talking about fight physics,
but they are not the same thing.
Let’s start with work.
Work is some force applied
over some distance.
Now let’s add in Newton’s Second Law,
that says force is equals
to mass times acceleration.
Now let’s add in one of
the kinematic equations
of motion, remember those chains?
And finally, we expand the expression.
Since work is also a
change in kinetic energy,
you have to apply a
force over some distance
to make something move,
we end up with the equation
for kinetic energy.
If the object starts at rest.
So the faster I move my mass,
the more kinetic energy it gets.
Now that we know how the equation
for kinetic energy works, we can explain
where all the power behind
a one-inch punch comes from.
Looking back at the
equation for kinetic energy,
we can see that an object’s velocity
can be much more important than its mass,
because it’s a squared value.
Secondly, we can see that force and energy
are related, but not interchangeable.
It depends on how you apply that
Wait.
It depends on how you apply that energy.
I said wait.
Rearranging values again in this equation,
we can see that the more distance
the change in energy occurs over,
the less force is imparted.
This is exactly why
cars have crumple zones.
The further the crumple goes,
the less force is applied to you,
and that’s good.
That’s why, to perform a
successful one-inch punch,
you want to do the exact opposite,
and bring all the kinetic energy
that’s in a fist to a
stop in a short distance.
Look at how short of a distance
this fist covers before the punch is over.
That increases the force.
Another way to interpret this relationship
is a change in momentum,
which is mass times velocity over time.
If you bring all of the momentum of a fist
to a stop in as short
amount of time as possible,
the force goes up.
I think this makes more intuitive sense.
The faster you hit, the harder you hit,
and Lee emphasized incredible
speed in his fighting style.
He was so fast, that some
trained martial artists
couldn’t even block his punches.
What happened?
This is how a one-inch punch
can impart so much force
by expertly minimizing
either distance covered,
or time elapsed.
But that’s not everything
behind the punch.
(karate yell)
Lee wasn’t a big dude.
He was my size, but apparently,
he hit like a big dude.
That’s because in both momentum
and kinetic energy equations,
velocity is critical.
And since I can’t change
the mass of my fist,
if I hit as quickly as possible,
I can hit like a guy twice my size.
Form is a factor, too.
If you didn’t have the concentration,
training, and focus to perfectly align
your kinematic chains,
force is gonna be lost.
With perfect form, you are
minimizing the distance
and time it takes to finish a punch,
thereby increasing the force,
but if your form is even
just a little bit off,
you will increase the
time and the distance
it takes to finish the punch,
and become like a car’s crumple
zone, lowering the force.
The final component of a
one-inch punch is psychology.
Look, when you’re being
punched by the most famous
martial artist in the world,
or who would become the most famous,
you’re gonna sell it a bit.
There’s no way this guy is actually
getting punched across the room.
Reputation has something to do with it,
and that’s kinda cool.
So why is the one-inch punch so powerful?
Well, it minimizes impact
distance and impact time,
it takes advantage of body
positioning and kinematic chains,
and it has a reputation behind it.
It’s never gonna be as forceful
as a giant haymaker
thrown by a giant fighter
because physics, but when
performed by a master,
it’s an incredibly efficient way
to produce a surprising amount of force
across almost no distance
in almost no time,
because science.
(groans)
oh, that was, oh dude, that
was more than one inch.
Thank you so much for watching, Joe.
If you want even more silliness,
check out my new show with
Dan Casey, my colleague,
where we get very silly
about a very serious man,
called Muskwatch and if
you want even more science,
but a little bit more
premium, check out my show
the S.P.A.A.C.E. Program
on ProjectAlpha.com
if you subscribe to that,
you can get that show
and this show two days earlier
than you otherwise would.
Thanks for watching, I already said that.
Thank you, though.
And thanks again to Birth of the Dragon
for sponsoring today’s episode.
The movie is inspired by true events.
To see the one-inch
punch on the big screen,
check out Birth of the Dragon
in theaters August 25th,
no cameras, no rules, no limits.
Come on, oh, oh, might
fly out of your hands
and hit you right in the eye.
Okay, hold it, come closer.
Alright, alright, one-inch punch,
using everything that we-
– [Woman] Are we rolling?
– Yes.
Everything that we just learned
kinet, kinet, kinetic, kinetic.
Come on, come on, ooh.
Come on, one more time.
Forget it.
(laughter)
He’s too good, can’t do it.
Okay, now hold it.
– [Woman] No, this is
gonna hurt your hand.
– It’s not gonna hurt.
Why would it hurt?
It’s styrofoam.
Alright, everything we just learned, okay.
Okay, see? We got the distance?
Hold it!
Hold it with both hands, hold it.
Put your hands up.
Okay, okay, okay.
– [Woman] I’m scared your knuckles
are gonna hit my knuckles.
(karate yell)
Yeah.
So you extend your fingers,
that’s the distance,
you have this distance.
– For force?
– Yeah, so you.
– Just like, like that?
– Yeah.
Stay away from my styrofoam.
You hurt my knuckle.
– [Woman] I’m sorry.
– Get outta here.

100 thoughts on “The Physics Behind Bruce Lee’s One-Inch Punch! (Because Science w/ Kyle Hill)”

  1. The "Kyle is wrong!" FAQ

    1. The episode is sponsored by Birth of the Dragon, and is not a commentary or evaluation. I'm only concerned about the physics here.

    2. I used footage of Bruce Lee's actual demonstrations when making the video, but did not feature those in the episode because of the sponsorship. Just a weird business thing.

    3. When talking about reputation, I'm not saying people are consciously "selling it." That's exactly my point. When you believe something is going to happen, that can be sold subconsciously. That's why these students think their master is magic: https://youtu.be/nu99GRUUN6Y?t=1m23s

    (UPDATING) — KH

  2. Thanks for the videos! Keep them coming!

    I just watched this and wish I had been watching the channel when it came out. Oh well, here I go (winging it). Hurrah!

    I trained in Kung-Fu for 5 years, specifically Hung-Gar (or Hungga, depending who you talk to), and got some rundowns on our outlook of the "one inch" punch. For us, it was not really about practical application, but an exercise and demonstration of technique, because this punch is all technique.

    Here are some physics elements I don' think were covered.

    Counter-Forces:
    -One of the biggest missing elements is from Newton's third law: For every action, there is an equal and opposite reaction. When you strike an object, some of that energy gets returned down the arm. This is not always the same. Consider the trick for crushing a can on your forehead. If you crush it beforehand, the can absorbs more of the energy of the collision and crumples. Whereas if you leave it intact the can may not crush and you can find yourself with a ring of hurt on your forehead.

    When my sifu (teacher) would talk about this, he usually talked about "rooting". The analogy was to try to solid like a tree at critical moments.

    -One way you can do this by subtly sinking your body weight, redirecting the counter-force downward into the ground (with carefully considered positioning to maximize this).

    -You can also introduce counter-forces, specifically you can turn your body slightly and quickly do a quick and well timed counter-thrust with your other arm (like a small elbow strike in the opposite direction). You could potentially also move one of your legs in the opposite direction, but this would probably be a contrary movement to sinking your center of mass.

    Stealing Torque:
    – You can engage your shoulders to add their speed to the fist, but also to get some of your should-related muscles adding to the strike.
    – Sinking your body can also allow you to hijack some of that downward force (gravity) into the strike. This is primarily relevant because the strike occurs below the shoulder. This can be applied more directly if the strike is angled more downwards, closer to the body (steeper angle from the shoulder), etc. However, too much of those would give you some unwanted tradeoffs.

    Energy Transference:
    – Most of these things involve energy being transferred about via those kinematic chains you were referring to. But in practical applications this is complicated by biology, such as the particulars of bone, muscle, fat, tendon (etc) position, composition, mass, etc. These are the sort of things that aren't well suited for my post here, but would be relevant.

    Other Things:
    – You notice that you start out with your fingers extended, and then punch from there. This is good for consistency when practicing. It's also good for show, because if you measure from knuckles to target, these are really more like 4-5 inch punch (as you mentioned), which sounds less impressive and is less catchy.
    More relevant, the shrinking of the overall size from open to closed takes the energy and puts it into a smaller area, increasing velocity.

    – You can also get some snappiness by keeping all your relevant muscles in a relaxed state, then triggering their contraction only when they are needed. So, during the milliseconds of travel in this case, you start in a state of relaxation, then the relevant muscles to begin your movement engage as appropriate, coming into maximum tension at the moment of impact. This grants you additional speed because your muscle system is a bunch os muscles and counter-muscles stretching and contracting, and tense muscles are more resistant to stretching. And ultimately what this is doing is trying to minimize the resistance to stretching of any counter-muscles to the ones you are looking to activate.
    In an actual fight, this is a way to minimize effort, energy, and strain to grant greater overall longevity. Relaxed muscles are also less prone to injury.

    – I am pretty sure there are a ton of subtle things I am forgetting. Sorry.

    Wrap up:
    The "one inch" punch is a great demonstration of techniques. Each contributing element does little on its own to a solid one inch punch, but when all minor elements are stacked on top of each other they can suddenly be quite relevant.

    Probably the most import use of a one inch punch is to teach you how to throw regular punches, or to improve your other techniques in general.

    Thanks again for the videos!

    PS: You, Randall Monroe, and Andy Weir should hang out.
    PSPS: I would love to be there too… please. 🙂

  3. 3:17 too bad. comedy comes in threes kyle! missed an opportunity to make it like, actually funny. still a cool video, love them always.

  4. You can one inch strike with more then just your fist.
    it can be done with your elbow, your shoulder, your head and even your hip. Or even done wile standing on only 1foot.
    The discription given on the show isnt acurate. its missing factors on how real short range power is generated. Elements of force like gravity are used, (often called using a falling step )as well as psychology like missdirection is used. (The more relaxed your target the better, so you hit when they are not ready for it)
    The short stop isnt part of it either. you still power through your target. if applied properly the kenetic force is aplied similar to a newtons cradle, the transfer of potental energy becomes the target either dropping unconcious, or if in a demo situation they move a large distance.

  5. Great video. Love the science. However, don’t rule out the Mass so easily. If the only part of my body moving is my arm then I only hit with the mass of my arm. However if my entire body is moving with the punch I hit with the entire mass if my body which is 10 times that of my arm. To do this effectively requires the proper alignment of the bones from knuckles to shoulder to maximize force from the mass without absorption of some of the force in the arm. Think of it as alignment of force vectors. Agreed velocity is critical but, 10x you multiplying mass and presto. Massive force in a short time over one inch.

  6. I wish you are my physics teacher during my high school. I never know how equations apply to our real world. If my teacher able to teach like you , relate what we learn to real world , I believe I would have choose other professions.

  7. have you seen how he actually punchs someone i do not mean in movie, in real life? reputation has nothing to do with.

  8. You forgot the point where the target received the hit is center of the mass. If he hit the shoulder, the target wouldn't be pushed away.
    Also, the force came from spinning your waist using leg as pivot, into your shoulder and then fist. So i don't know how that works with the physic though.

  9. I practiced this with my bro and it did send us flying back quite a bit. We practiced with a bed behind us, but neither expected it to work. the other person has to be relaxed though. We expected to fall, just not to almost hit the wall. It felt less like a punch and more like a massive shove.

  10. Kyle, have you tried this on drywall? It's in your nature. Would slamming a monster and a white claw cause you to go super smash bruh and be able to punch through more than drywall?

  11. You say they sold the punches. Okay I can see where that may be true. Watch this video of the Long Beach Tournament. Start at 3:14, doesn't look like too much selling to me. That chair slides quite a long distance. https://www.youtube.com/watch?v=AqHqMdRcROQ

  12. You need more research. What you’re explaining is lacking one element. You obviously don’t know how the wing chun punch work.

  13. Thats what im thingking as well. Thats not 1 inch, so where and who started calling it 1 inch punch then?

  14. Late, but the trick to it is you make space to line your body up while you elbow and wrist turn by 90° towards your centerline.. its not a open motion, its a twisting punch. <3 great video.

  15. God damn all the gags are so fucking annoying, You are not funny… They come every 10-20 seconds… Fuck this vid.

  16. Personal opinion, I believe that the One Inch Punch is so titled because that is the distance in which Bruce's closed fist traveled before the punch connected with its target.

  17. Great video, however just to share with you that kinetic linking is also a part of chi. Chi can be recognized as the flow of energy. And when you get the flow of energy flowing in a direct connected line you get a powerful punch. That's why it martial arts we focus on form and structure that way when you come to a real fight if you're able to utilize your form in your structure you pack a lot of power. And by doing so allows us to rapidly build Chi and hit hard. Chi is not a magical Force

  18. Damn i really understand how that works now thanks to you amazing i didnt think form produce the enegry of that size

  19. Basically it's what I said as a kid when my friends and I talked about this. He's putting his weight behind the punch instead of using arm strength alone. You see it all the time in recreations of the famous move, and to the same degree when martial artists are displaying technique. By throwing your weight behind the punch you can hit harder than you normally could. It takes discipline and training to do it effectively though. Throw yourself into too much and you lose your balance. Or you leave yourself open to a counter attack. What I'd like to see is the factor by which an asteroid's impact increases depending on whether it's broadside shot, hitting the earth on either side or from the rear, compared to a head on collision. Both objects racing towards each other.

  20. I haven't watched it but i will say from the beginning that it is actually a one inch PUSH…..his follow through with his fist after the "punch" is what creates the illusion of a powerful punch, but in reality it would not be a viable technique to actually use in any combat situation where you want to inflict damage. You can push someone over very easily, but it wouldn't result in any damage unless they hit their head or landed wrong etc etc. The one inch punch is technically bullshido and yet another of Lee's tricks to seem much more impressive to people that don't understand what they are seeing.

  21. There is a difference between a one-inch punch and a three-inch punch. A three-inch punch is extended finger distance. A one-inch punch is at a distance of one knuckle.

  22. That's not how it works. I have been doing martial arts for 20 years and the one inch punch has nothing to do with science or the fame of someone. You don't understand chi at all. If you want to see how it works then try getting in by it then you can talk about. I can do the one inch punch. I have video of me braking boards and brick's

  23. I am think you must be very desired by many, You have a Thor look with the face and hair and a Ironman intellect, WELL DONE in your brake down of the science.

  24. Great that you can explain this in the form of an equation. Now make this a reality. Show us how it was done. Bruce Lee could do it. So this idiot writing out formulas should be able to translate those formulas into physical action. Just a bunch of nonsense & hot air spewed.

  25. Been practicing Wing Chun for 20 years. A couple of things. One, the one inch punch, when done with the fingers fully extended is called the 3 inch punch. With the one inch punch you hold your hand very much like a gorilla when it walks. With your second knuckles pointing at your opponant. Two, applied without experience, the one inch punch will not send people flying as Bruce Lee does in the film. However a huge requirement to use the one inch punch is a keen understanding of a persons center of gravity. Placed properly the one inch punch will knock them back so hard that the opponants feet come off the ground. If a big dude did this he might be able to send you back a foot or two. For regular sized people your opponant will stumble backwards quickly and comically or they'll fall to the ground very fast.
    four, the one inch punch originates in the Wing Chun discipline. Wing Chun utilizes multiple vectors of force to multiply the impact. To properly do the one inch punch your arm must be slightly bent and your body dropped. Like a coiled spring. You "burst" your body towards your opponant and extend your arm to complete the punch slightly after you "burst" forward. This greatly effects the power of the 1 inch punch. I've never knocked someone like they do in hollywood but I've sent friends and sparring partners 6-10 feet back several times. They don't go flying but they sort of stumble backwards very quickly.
    Finally, a lesser seen use of the one inch punch; If you do the one inch with a slight arc and apply downward force you will break their structure and drop them straight to their ass. With enough force to break their tailbone if they happen to be on a hard surface. (I use it to put my friends in their chair sometimes)

    Extra note, in Wing Chun the one inch punch is a basic concept that is to be applied to all strikes. This isn't well known because few students gain the proficiency needed to go beyond using the one inch punch as a gimmick. Again it's multiple vectors of force at work here. Just imagine that you throw a relaxed punch but 3 quarters of the way through you flex and finish that punch like you mean it. I was told the multiple vectors double the impact force but I don't know if that's literally true. I can tell you it hurts your back when you get hit like that. Even if you're hit from the front. Literally had my back cracked from one of these punches. Which is startling to say the least.

  26. You do realize it was actually a seven inch punch, right? Bruce threw all of his punches to land six inches behind the intended target. How they filmed a movie called Birth of the Dragon and left that little bit out is ….surprising. Good video, but your science is a bit off, for the same reason.

  27. You missed some info Bruce lee was also very strong, he used special made extra heavy “heavy bags” made of leather sand and aluminum, 4 times the normal weight, every body that fought him said he hit like being hit by a truck.

  28. it may be true that some people will sell things, but the force of his fist can crash through a solid block of ice, and his movements can rip a car door mirror off a car. The part your missing is you dont just make it come to a stop to create more force, you push it into the person. You would cause a greater change in momentum if you push into someone then just imparting a single blow. Plus the sudden action of it causes people to stumble because you dont expect so much force, even if you know about it. I don't think people will sell it like you're showing with the chi master guy, thats something different.

  29. Pretty bad explanation: first: if he understands, how physics work, why is he not able to realise that his punch at 8:03 cant work, because she is holding the styropor flexible with the fingers and not with the palm of her hand and also with bend arms and not rigid, this way giving way to the force and transfering the energy over time, instead of instantly?
    WE have to differentiate between two kinds of "one inch punches": the one to move a body and the one to break a board.

    The "one inch punch" demonstrated with an opponent is about PUSHING somebody. Pushing is a rather slow, deep penetrating motion (deep: this means you are accelerating the body of your opponent over a longer time: this means more force transfered) with lots of weight AFTER first impact. The breaking motion is a rather fast movement with less weight before impact. You get into problems to break even a thin layer of styropor with a slow pushing motion. So the styropor is the wrong material to visualise what Bruce was doing. The right stuff to visualize the one inch pushing punch to throw back a person would have been a moving heavy bag.
    Third: at 5:00 he says: "And since I cant change the mass of my hand..(I have to hit as quickly as possible)" Untrue: the trick is to actually change the mass of your hands: because you are not punching with your hands: your arm has to be straightend out. And via your arm through your fist you are transferring the whole mass/weight of your body into the punch. So you are punching with the body. And since this is not about your fist, the speed with wich your fist travels before impact is not that important. The speed of your bodyweight shiftig forward after impact is important for pushing.
    In contrast: for breaking a board with a one inch punch you would need a fast movement of the fist before impact.

  30. Bruce Lee did not create the 1 inch punch. He learned it from his Wing Chun Master: Grand Master Ip Man. All techniques and movements in Wing Chun are based on having a properly aligned skeletal structure. The 1 inch punch is simply a close distance "push", not based on speed at all but entirely based on a solid stance. Any "good idea" or "innovatine philosophy" Bruce Lee came up with was stolen from Wing Chun. It's just that most ppl in the western hemisphere were/are still too naive. People still think Lee was as some "mystical guru" yet he never actually mastered a single martial art. He was just a great actor and had a way of fooling people who don't really know about true martial arts.

  31. The punch in the movie clips is the 3 inch punch. Bruce Lee's 1 inch power punch starts with the hand in a very loose fist, tilted down. Index finger extends slightly to just touch the target.

    It starts at your back foot and travels through your body.

  32. I never mastered the “one inch punch”, however: I am both military (US Army) and martial arts (Kung Fu and Kuk Sool Won) trained. That being said, My classmates at my former Kuk Sool Dojo eventually learned to refuse to perform “live spar” exercise with me. Why? Simple: I am 5’7” and a mere 130 lbs. That which I lack in size, I easily make up for in speed.
    E.G. : While my “heavier” opponents (classmates) were “cocking the first kick”, I would usually have unleashed 3 “non-cocked” kicks ( usually to the knee, ribs, and shoulder or head depending on target height). When sparring in class, we would always be taught to withhold our full force… but, even when I withheld I still created !

  33. This was an intersting/fun video. I can't totally agree with the theory about part of the punch's effectiveness being credited to the person's reputation, because Bruce Lee didn't have a reputation in the martial arts world at the time. That tournament was his introduction.

  34. There are two other physics points and one "mystical" that you didn't covered.
    The one inch punch specialists get more velocity by keeping his arm and hand relaxed until the last moment before hitting the target. A relaxed arm get more velocity then a tensioned one, and also the effect of tensioning the muscles just before the impact increases the damage. For those who had been hitted by this movement knows that it looks like an inflated ball turning to a steel ball inside your chest.
    The mystical point is the training of the Chi, where these guys learn how to do amazing things with their muscles and breath, including really quick muscles tensioning, which improves much more the effect over the target. I'm sure a well trained person could cause heart attack, broke the bones and cause really dangerous internal damage.

  35. Accurate math, but communicating some wrong concepts. It's not about the mass of the fist… that's literally irrelevant. That punch would be virtually identical if he were wearing gloves with 3x his fist's mass. The formula would suggest this would triple the force of the punch, but it doesn't… because his fist isn't actually the thing doing the work. Kinetic linking is definitely the key… but his arms aren't pulling their weight at all. He's pushing with his legs, rotating his hips, and essentially delivering a 1-3" shoulder tackle (with the mass of his torso)… the arm and fist are essentially just there for extension… they can actually stay still and do no work at all, so long as they're rigid on impact so your arm isn't absorbing any of the impact.

    The mass of the "fist" itself isn't the right variable.

    A REALLY BIG guy punching with his arms vs. an average guy delivering a shoulder tackle through his fist (at equal speeds)… the smaller guy using better body mechanics will hit harder because you're comparing the mass of an arm vs. the mass of a torso. (neither just use the "fist" by itself)

  36. One thing that must be said here: minimizing the distance would only increase the force if your final velocity did not change. You would need to accelerate insanely well to get the same velocity, and that will of course increase force, not the distance.
    Second, and I say this with some background in martial arts, if the one inch punch were that good, you'd see pros doing it. Bruce himself only did the one inch punch on volunteers who just stood straight up with legs locked. When he sparred though, he used techniques that were actually effective.
    Sorry, but this movie is just another Bruce lee worship video, of which I have seen way better.

  37. Hello, …love the video!
    I studied partial physics are the University of Texas in Brownsville and I've train in martial arts (mainly Taekwondo and Eagle Claw Kungfu) for over 25 years.
    I confirm that your explanation of the One Inch Punch is all correct. However, there is one detail that you left out.
    In all martial arts, perfect form is essential. Along with that, when throwing ANY punch, you must punch THROUGH your target, not stop at your target.
    If an 18-wheeler was coming at you, but it came to a dead stop just as it was about to touch you, the air pressure would push you back some. But you would not be seriously hurt.
    The truck would have to drive through you to hurt you.
    This is the same concept when throwing a punch.
    The same concept is emphasized in many sports like tennis and golf. You'll constantly hear coaches yelling, "Follow through!"
    I've successfully performed the One Inch Punch many times. I obviously don't have the fame of Bruce Lee. So when I throw the punch at someone that is not expecting it, they either fall back on their butt or they stumble back about 1 foot. The target's mass plays an important roll. And by the way, I'm 5'9" and weight 210 pounds.
    Again though, over all, great video.

  38. The scenes in the movie you showed looked a little too "Hollywood" in how they portrayed the 1 inch punch. If you look at 1967 video of Bruce Lee doing the 1 inch punch, you can see he kinda twitches his whole body before "bursting" the energy through the punch.
    Those scenes in Birth of the Dragon, it just looked so casual and trying too hard to look cool.

  39. Wait? Wouldnt reducing time or distant only mean that bruce would have to hit with more force instead of just somehow create more force on impact.

  40. The problem with using movie clips is they don't really show the 1 inch punch correctly. It's not a fighting technique. It take a moment to set it up and nobody is just gonna stand there while you prepare to punch them, Lee only used it to to exemplify the force he could apply with his striking technique. And he never knocked anyone across the room with a 1 inch. He could do that with side kick, but he typically could knock a full grown man back a few feet into a waiting chair with the force of his 1 inch. The math is interesting, but the physical elements aren't as complicated as it seems and are explained clearly in his book Tao Jeet Kune Do.

  41. I wish you had used actual footage of Bruce Lee's one inch punch.

    The movie version was magic.

    The actual attack, you could see his stance, his body go from limp to completely rigid and follow the line from his back foot to his fist in less than a second.

    The people got hit with the entire force his body could produce from the ground in that short of a distance. It is like the peak version of martial arts.

  42. The first mistake was to take the punch name literally because it is easy and logically already explained but very hard to master. But I like your physics approach so i will let it slide :). Probably what Bruce would have said…

  43. Kinetic linking is something your taught in martial training. E=mc2. The power is already there, in the ground and your body. But he has already put his body in position to generate the Force needed. I've studied a similar technique in board breaking. The perfect version of the move doesn't require any space at all. Not even one inch.

  44. Nice video !! I just wanted to add that this was never BRUCE LEE's PUNCH. This punch comes from any Chinese style. Kung fu relies on A. Great foundational stance . B. The whipping of the waist. C. Arm placement/technique with the elbow inside the body.
    There are a lot more details involved that takes thousands of hours of training to get the technique right.
    You have to also know how to relax and contract your muscles in a certain way. If the body is too right or too rigid, you cannot generate speed and power.
    The power from the punch is actually coming from the ground.

  45. Congratulations, you finally analyzed a martial arts technique correctly and accurately. Only thing is, a wide swinging haymaker might generate more force, but it does so in the most terribly inefficient way possible, and is the dumbest way to punch in existence. Also, she moved her hand back when she punched the styrofoam at the end.

  46. Pretty good. You almost got it spot on. But you missed a calculation in your own data. Because. Fighting. There are two types of ways you can deliver an energy OR force in a fight. Internally and externally. So no, a larger haymaker does NOT mean a harder hit. A haymaker or even a hook will only deliver EXTERNAL force or energy. The once inch punch, delivers all energy internally. Its funny that you missed Bruce giving YOU a physics lesson. And I quote him now. "Karate is like being hit with an iron bar, Gung Fu is like getting hit with an iron ball attached to an iron chain" end quote. Thats verbatim. External vs internal. Yes a heavy punch can knock someone out. SO can a one inch. What a once inch can do that a heavy CANNOT, is burst an organ or destroy internal systems. Your science is great. Just your fight knowledge is a little low!!!

  47. It's already been labeled a 3 inch punch a 1 inch punch is when the fingers are folded and hand is bent. I do know the movie show and labeles it wrong but I'm just stating a not so common knowledge.

  48. I snap real solid 3/4 inch boards all day long with a one-inch punch I'm sorry but you're mistaken you need to use your head … 11 pounds with neck movement at the same time all of that energy from your toes reaches your knuckle is a force that cannot be stopped I am the humanoid

  49. What If Bruce Lee Bones Are Made Of Adamantium & Inside Him A Vibranium & Mastered The Four Elements(Water Earth Fire Air) & Ultra Instinct

  50. It's kind of funny he's sorta kinda just explain what Chi is which is gathering and linking the energy throughout your body

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