I was a karate practitioner and instructor in my youth. Board breaking is really, really easy. The key is the boards designed for breaking are cut in their weakest orientation. Wood is incredibly strong going with the fibers, even a pine board is very hard to break long ways using a sledge hammer. However, if it's cut on its short axis, it's incredibly easy to break. Most people, even children don't need any guidance beyond, "punch through the board" to be successful. Breaking boards is more mental than physical. If a student is struggling or a novice, the person holding the board can hold their hands a little wider to make it easier to break.
Concrete is more difficult, but there's still a trick to it. The blocks you use for breaking have a bit of flex to them, but are also extremely brittle. So just getting it to flex just a small amount will cause them to break in half. That's also why you place spacers between stacks of bricks or wood. You're leveraging the flex of the material to break it, and stacking them without spacers makes too rigid to break.
I would say, kinda but not entirely. IME as a practitioner in my youth, I would say that breaking the mental barrier to throw a good punch is a thing that needs to be broken as part of the martial arts training. Another thing that a good training gives you and not many people understand is the preparation to receive a punch, not cower in fear and still keep a sound mind to try to recover and react.
Your board holders also have a significant input on your success. If they hold the board, but let their arms flex, then they absorb too much of the energy of the strike. They can make it easier for you as well, by flexing the board inwards towards them.
I've gone through boards with a one inch punch with barely any effort, and also failed several times, and it has always been down to the person or persons holding the board for me.
The only board breaks that are really impressive to me are speed breaks, where the board is either held one-handed (either by the person doing the break or an assistant) or is mid-air when struck.
But shows you just how easily they do break. However because we think “board” we assume it’s cut grain wise like a normal person. They aren’t and are about as strong as a chopstick.
Totally agree. But a long time ago I saw a take kwon do guy break stones like you find in a river bed with his fist. I remember later on I saw his hands and they were almost crippled. They were huge and didn’t seem to have too much movement left. I think he broke them many times and would grow a lot of bone that way. Same way some muay Thai fighters have super solid shins.
we had a guy at our studio seriously into this. you have to train a lot: hit bags of rice, then beans, then sand, then steel shot. eventually yes it tends to cripple your hands though that can be somewhat mitigated by rigorous mobility exercises and basically PT. still do not advise.
note that almost any fighters knuckles will be more solid as the lattice structure of the bone gradually fills in. that doesn’t cause as many mobility issues, it’s when you get new growth on the outside that problems start.
This reminds me of a clip I saw of an older martial arts practitioner, like heavy-duty, far east, everything was translated. He had spent decades punching harder and harder things until he had to hit opponents at a small fraction of his strength, as his forearms on up were mineralized clubs on the inside. A full strike could kill.
I watched closely and his hands didn't seem to be much use for anything else.
There are two shin bones and if they fuse there is a lack of mobility. A lot of muay Thai fighters have problems with their legs later on. That in addition to the obvious which is brain damage and a lot of scar tissue in the face.
Huh, I had never even thought of the tibia and fibula fusing, does this really happen often in Muay Thai? I coincidentally just got back from training at my Muay Thai gym just now. The first few weeks or months of training there’s definitely a lot of welting on the legs, but the shins adapt quickly. I hadn’t heard of the shin bones fusing.
I knew some fighters. One of them was a low kick specialist and his shin felt like one solid piece of concrete. Not sure if it was fused but he couldn’t do certain movements , but he could kick with unbelievable force. I have no idea how his opponents could block this with their own shins. Many years later I still have some sensitive spots on my shins from trying to train with them. It was impossible.
I did Kyokushin karate to Shodan. The board we broke were solid pine boards. They are definitely not "cut". My technique was a little off, and I wrecked my knuckles for months. They ended up permanently moved.
Not cut as in pre-broken (though I’ve seen that too), but cut as in the original action which turned the log into a board. The boards are formed the “wrong” way if you wanted strength, like for building.
Take one of your boards and hold it with the grain horizontally instead of vertically. Try not to break your hand.
I think that most people just take a regular board and cut it into several lengths. Since the grain generally runs along the longer dimension of the board, that means that you break the board down the middle.
It's called "martial arts" because originally these were skills used in warfare. "Art" here does not mean "dance and performance"; that is a more modern definition. Sun Tzu's The Art of War is not a theatre guide.
On a semi-related note, "liberal arts" refers to the skills that would be required to participate in a free society, particularly to participate in informed discussions on social and political matters. That's why liberal arts includes subjects such as math, science, geology, and public speaking. It feels like many people are not aware of that, which ironically is due to a want of proper liberal arts education.
It really depends on the style and the gym, and whether you're doing it for fun/fitness or competitively.
I've spent years doing no contact karate, and years more doing full contact (but not full force) sparring in Thai and Western kickboxing. For the latter, there's not really a performative aspect to it. Nobody is watching, there's no forms, no real room for fancy flourishes that waste time. I get punched in the face a lot (I'm not very good), and have had the wind knocked out of me many times. I've also spent significant time doing the song and dance (literally) kickboxing at the local YMCA, which was more like Zumba than traditional martial arts.
All of it is great fun and exercise. There's nothing wrong with any of those approaches as long as it fits what you're looking for. There are a LOT of gyms and styles and teachers out there!
Yes and no. There is a lot of performance in demonstrations and movies, still it is quite effective for a very well trained practician. But the most effective techniques don't look impressive on screen.
It depends on the particular martial art. A lot of very famous martial art styles are purely performative, and are basically no use in any fight with a non-cooperative opponent or at least one not practicing the same restricted move set. Some of this was quickly demonstrated when a few famed practitioners made the mistake of participating in MMA tournaments. Some examples of such purely artisitic/ritualistic/sporty arts are sumo, aikido, capoeira, Krav Maga, and quite a few others.
Lyoto Machida uses Sumo as part of his MMA. At our school we've found it's pushing techniques useful once your get an opponent off balance.
The locks in Aikido are useful as pain compliance techniques used by people like law enforcement or bouncers. Compared to an art like Judo, the "throws" in Aikido generally don't throw your opponent to the ground and do damage. Instead they tend to cause your opponent to stumble away from you. Therefore, they aren't very useful in competition but they are useful in self defense where they can create an opening to get a weapon or escape.
Dance and performance has been part of almost every warrior tradition that I'm aware of. The Spartans had Gymnopaedia, Europe (along with many other areas) has numerous sword dances, the Maori have haka, Muay Thai has wai kru, modern militaries have drill, etc.
Dance appears to be a very natural and primal form of human ritual, so it's not surprising that most cultures have utilized it as a way for warriors to build confidence and demonstrate their attributes & skills.
>A lot of it is essentially dance and performance.
While it may look like a dance when a single practitioner is doing a kata or “form”, it’s anything but a performance or a dance. There’s full contact, pit, octagon, Bellator, K1, and various other avenues to “practice” your martial art on someone’s face.
> A lot of it is essentially dance and performance.
The "dance and performance" (kata?) is essentially slow-motion practice of moves and responses. You are muscle-memorizing moves that you would deploy at full speed in a non-pratice scenario. It certainly looks like dance, and it feels a bit like dance too.
Because it's slowed-down continuous motion, you have to concentrate on keeping your balance. When that's translated to a non-practice scenario, it results in greater precision both in terms of motion and of force-delivery. Performing katas also develops strength; I gave up tai-chi because after every class, my whole body would ache.
That tends to be a translation of Japanese "bugei", where the latter part also translates as craft or technique. "War(rior)craft" or "warrior techniques" would be valid translations too; generally modern society wants to de-emphasize the war part. And Japanese society historically saw poetry in death..
Hell, that's why instead of saying "warrior" or "war", the English term is a euphemistic reference to an old god -- god of war, sure, but an indirect reference, suitable for polite society.
Your hand might not break, but it still really painful.
Breaking a stack of 6 with a knife hand, my wrist would usually be sore and bruised up the next day. It would take a week or so for full mobility.
I still think most people in the world wouldn't be able to break 2 pavers with no spacers. :)
Interesting. I was doing this kind of stuff in high school, never had such problems and I don't know personally anyone that did (and I used to know a few dozen people practicing various styles of karate). In any case wrist pain suggests a very bad strike technique or weak wrist muscles.
It sounds like 90% grit and 10% magic trick, but you were an instructor so I’ll take your word for it.
I still wish to believe that the crème de la crème, or the top 0.1% of the karate world, can muster enough force to break concrete regardless of any tricks.
Breaking a board with some techniques is easier than others. The front-leg hook (also known as "whip") kick I personally found quite hard to break with, particularly when jumping. Two boards, no spacer, palm strike was much easier for me.
Ice is very similar to concrete pavers; it's both rigid (i.e. requires a lot of force to deflect), but brittle (i.e. takes very little deflection to break).
Still, nothing will detract from the visceral wonder that I could never forget after seeing, in person, an extremely high ranked karateka (i.e. second in the world, in his style) chop a seemingly solid block of ice over a foot thick.
I suspect that, while there might be "a trick" behind these things, extreme achievements in that field are still rare and accomplished acts, as they are in any. The wonderment need not be fully extinguished.
Oh, it's absolutely hard, but like many things the apparent difficulty and actual difficulty are only loosely related, and good showmanship (perhaps a more polite term for "trick") will involve maximizing the apparent difficulty while keeping the actual difficulty manageable.
You see similar things with e.g. juggling where entertainers will do a lot of things that make it look harder. This doesn't mean that it's not difficult to juggle 7 objects.
I think that people might be using "trick" in two different senses.
There's a "trick" to legitimate breaking in that the practitioner is choosing materials and techniques that lend themselves to breaking, but that doesn't mean that the actual break is faked.
On the other hand, it's also possible to fake a break. For example, you can cut a piece of ice in half, put some water on each end of the cut, and stick them back together in the freezer so that the ice appears to be solid but actually has a weak spot.
There can also be an element of showmanship. Even if a martial artist has done a break dozens of times, during a demo they might make a show of having to hype themselves up for the break, tensing their muscles with a dramatic hiss of their breath, etc.
Thank you! I saw that article and i was like "wait, what?? are they not aware that this is mostly a parlor trick???" I thought everyone was aware... No science needed, it's a trick.
I did martial arts for years and often helped out with the classes as an adult. We used to buy the cheapest concrete brick/paver we could get for breaking. Something similar to this:
There is a lot of variance in bricks. And honestly a lot of the cheap ones would break if you dropped them, or loading and loading them in the van...
Not to mention people would accuse us of baking them, or freezing them, leaving them outside for months or years, all kinds of stuff. But honestly we would buy a bunch of them from the home improvement store on the way to the demo at the mall or a school. You'd be surprised at how easily you can break one with the simple tap of a claw hammer.
It's just physics. The longer the brick, the easier it will break. Some demo rocks are much longer. The trick is to hit it fast, use the smallest impact point you can, and follow through. If you don't follow through you won't even be able to break a pine board. Theres some kind of psychological thing prevent most people from punching through a target, whether it's a brick, punching bag, or a board.
Walls generally have studs that are 1.5" wide every 16", so more than 90% of points on a wall are not in front of a stud. You do need to punch a few inches away from the stud to account for the width of your hand and to get enough leverage to break the drywall, so maybe expand the width of the hand-break-zone from 1.5" to 8", and you've got around a 50% chance that punching a random spot on the wall avoids a stud.
> so more than 90% of points on a wall are not in front of a sud
That would depend on the wall length, no?
For example, a 1.5"-3" wall has 100% of points on a stud. Also many (most?) traditional residential constructed walls have end plates, at least one top plate, a bottom plate, fire blocking, support, kings, sisters, cripples, jacks, headers, etc.
Anyway, I think its probably safe to say more than 10% of the surface has wood or some other object behind it on many walls, and unlikely that you could "do the math on this" without surveying data.
The top and bottom plate are unlikely to get punched, as you're going to tend to punch towards the middle height wise. Fire blocking became required by code in maybe the 80s or definitely in the 90s; there's a lot of older housing that may not have it. Also, it seems like a lot of this punching or kicking of walls happens near doorways, you're going to tend not to punch the wall near the doorframe, and if you go in maybe one shoulderwidth, you're not likely to hit a stud.
One of my friends had the "brilliant" idea of playing "drywall roulette." In a room about to be demoed, run headfirst into somewhere near the center of the wall. First person to hit a stud loses.
I punched a wall while mad and put a hole in the drywall. I didn't plan where I was going to hit it. I'm not proud I did that though. Firstly, for losing my temper, which is not who I strive to be. Secondly, it's obviously weak material. I'm sure a lot of people have.
I used to have a rage problem until about 5 years ago. I broke a number of phones in the few years before that, so I bought a rugged one. In my last ever bout of rage, I threw the phone at the wall. I expected the phone to break, but instead it made a hole in the wall. I spent ages researching how to fix it and in the end ended up using quickfill and painting over it several times. From that point onwards, I've always preferred handstand pushups when I'm feeling agitated.
I assume selection bias is in play: for every post on the internet there are many more who did break their hand and ended up in ER, they were just too ashamed to talk about it.
A kid I went to junior high school with said that he put his head through a wall--he was wrestling, and the other guy threw him. I was a bit skeptical, because I then lived in a house with plaster and lath walls, and had not encountered drywall. But I expect he told the truth
I did years of martial arts training, including the board breaking stuff. Then I made the mistake of stepping into the ring to spar with a boxer half my weight. He wiped the floor with me, using only one hand.
Yes, "martial arts" is a fun way to get some exercise and build a little confidence, but never make the mistake of thinking that you actually know how to fight.
There's an entire universe of difference between someone who takes martial arts classes a few times a week, and an actual trained fighter. I trained in boxing for a few years, and got to the point where I can trivially defeat an untrained fighter who's bigger than me, and easily defeat a less experienced fighter. But even then, against a professional fighter who trains all day every day, I'd never stand a chance. I once watched in disbelief as my coach defeated our star pupil (who was getting too big for his britches) with BOTH hands behind his back (basically just dodged and smashed him with his shoulder until he fell down). You simply could not hit him or even touch him, while he could pick any spot he wanted on you.
Fighting, like any skill, takes a long time to master. And there are no "mystical" routes or special ways or short cuts. Only hard work and regular practice in real combat.
“There's an entire universe of difference between someone who takes martial arts classes a few times a week, and an actual trained fighter”
To echo this, I have professional competitive experience in Muay Thai (and also in some other combat disciplines). My training schedule during this time was 2 x daily, 6 days a week with a 4km run before each session.
With this consistent routine training alongside other young, hungry and often gifted high level fighters, it takes something special for a hobbyist to join in a Pro session and not look ‘out of place’.
If you are training right, every angle, strike, and position is carefully mapped into muscle memory even for when there is nothing left in the tank.
Non competitive Martial arts are superb for confidence, but be very sure, there is (like you said) a universe of difference between an active professionally training fighter and a talented hobbyist.
Ah jeez, I was hoping for more about the alignment of structure in one's body to apply the greatest precisely-directed force (etc.), but it just focuses on the gimmicky stuff I find the absolute least interesting about martial arts (the showy "breaking objects" stuff)... The post should be titled "why our hands can break wood and bricks but not bones". The physics of karate are pretty fascinating, I would love to read more material that discusses the subtle differences of positioning, momentum/inertia, "spring action"/compression, all that kind of stuff.
Anyone have any suggestions for youtube videos on breaking concrete? My kid has an upcoming TKD black belt test and the master said she can do the concrete if she wants, but doesn't have to (she's 10 and very small for her age). I've watched a few youtube videos about this, but all of the demonstrators are grown men, and the seem to jump and use their body weight as they're coming down.
Suggestion - what about just not doing it? Like the article says - it's all physics. No matter fast and precise she is, a small 10 year old girl will have a harder time generating sufficient power to get the break without some risk. And for what? They'll still have concrete blocks around in 5 or 10 years when she's bigger if she still really wants to do that break.
My 10 year old is a hefty guy, and I'm personally not crazy about him breaking boards too much.
Yeah, we haven't had her practice for this reason. I'm not sure the physics works for a small kid. But the master wants all the kids to try, and he's instructed them on how to hold their hand to avoid injury.
Not sure why they expect a 10 year old to break concrete. It's not even worth trying, it's a completely pointless ability and your daughter can easily injure her hand smashing against a brick. Unless the goal is for her to be a sport/tournament fighter, but I assume the intent is to learn actual life-relevant self-defense abilities.
When I was in martial arts, breaking landscaping blocks with a palm strike was not difficult at all, but did sting like a hard high five. The trick is a stiff hand, but not so stiff as to be inflexible, and hitting mostly with the meat of your hand.
A regular punch or knife hand is much more prone to injury because of the more fragile bits being closer to the action.
I’m disappointed this was all about the stunt of breaking things. I study Okinawan karate and true masters generate tremendous power via the tantien and rooting into the ground. It would be interesting to read a western analysis of that.
I don't know about Karate but in boxing you exert extra velocity through the movement of the whole body starting with the feet when punching. Kinetic energy is 1/2 m * v^2.
Yes there are some really strong people out there who can break the boards in a legit way, but most of the time the boards are simply discretely cut before the demonstations. Thanks to those cuts (and orientation of wood) the boards become very easy to break.
That's what my friend used to do. Also he gave the real (=not altered before) boards to people he didnt like and they couldnt break them.
I cannot tell if most karate demonstrations are fake, but breaking some wood or concrete is regularly done properly in demonstrations. I practiced karate during high school and college and we were breaking stacks of ebonite electrical contactors in high school for fun, as we had a large supply of these. Most people were able to break 1 or 2, the top did 5-6, that stuff was hard but we were young and stupid and did a lot of crazy stuff (still stupid these days, but no longer young :) ).
It says that you need 2,500-3,000 newtons to break concrete, which a hand can produce:
> the hand of the karateka, or practitioner of karate, can… exert a force of more than 3,000 newtons
But then fails to explain why this doesn't shatter the hand:
> Human bone is five times stiffer than concrete and fifty times harder to break (successfully karate-chopping a femur would take more than 25,000 newtons’ worth of force). The bones in the hand are easily able to absorb the stress of the impact.
I mean sure, but karate chopping is done with the hand, not the femur. The femur is the largest bone in the body, in the leg!
And if it takes 25,000 newtons to shatter the gigantic femur, it seems entirely reasonable that it would take only, say, a hundredth of that to shatter one of the tiny carpal bones in the hand, for instance. Which would be 250 newtons, far below what it takes to break wood or concrete.
And even if bone is 50 times harder to break than concrete, the bone that absorbs impact first is tiny compared to the piece of concrete.
So even after reading this article, I have no answer whatsoever on why the tiny hand bones don't shatter.
Is it something about the bones' arrangement? Their flexibility? Something about the properties of the ligaments that connect them? Something to do with our skin? The level of compressibility of water?
Yes, from the title I have also expected a much more complete explanation about how to hit for a successful tameshi-wari (test of breaking).
In the martial arts there are 5 or 6 traditional rules for how to hit for a maximum effect, and all of them can be explained by modern physics. The most important 3 are the following.
To achieve maximum acceleration, you need maximum force. For maximum force, you need as many muscles as possible to participate in striking. The most powerful muscles are those of the legs, so they must also participate when hitting with the hand, by rotating the hips, whose movement must be transmitted through the abdomen and thorax until the hitting hand.
To achieve maximum final velocity of the hand, the hitting arm must not move like a rigid stick, but like a flexible whip (more accurately like an articulated flail), with a wave propagating along it so that the extremity will achieve a maximum speed, much higher than the speed of the extremity of an arm-length stick that would rotate around the shoulder. For this, all the muscles that do not contribute to the acceleration of the hand must be as relaxed as possible.
To achieve a maximum transfer of energy into the hitting target, it is necessary for the body part used for hitting to have a maximum equivalent mass. For maximum equivalent mass, the ideal is for the entire body to behave as a rigid body. This can be achieved by a contraction of most muscles. So in contrast with the time before the hand reaches the target, when most muscles should be relaxed, during the very short time of the impact most muscles must be contracted. In many Japanese martial arts this is somewhat confusingly explained by some mumbo-jumbo about "kime".
Yeah! thank you! this comment is better than the whole original post! Very well-worded. You must practice some martial art? (no obligation to disclose, just curious)
I have practiced for many years some Okinawan styles and also Japanese judo and aikido when I was young.
Unfortunately later when I became much busier with my profession I have never found again some place close enough to my home to be able to go there regularly within the little available time.
Nowadays I only practice solo exercices for preserving health, but this is still a very important benefit of what I have learned when young.
Ah nice! I'm glad you're still doing some regular exercise/practice. I learned a bit of aikido when I was young too, and more recently have had some very nice 1:1 instruction in shotokan from a VERY experienced practitioner. I can see how mastering even just one or two kata can be a valuable practice throughout one's life, outside of the self-defense benefits. I like that there's always more to learn, and greater subtlety to understand and ingest. Very rewarding and mentally/spiritually powerful. (not to mention great exercise haha)
Stuff like that is why I laugh a little at cyberpunk "cyborg metal arms" stuff.
Sure, it opens new possibilities for when you really need to be able to crush rocks with your hands, but often people don't realize how much our default equipment--literally nanotechnology beyond human understanding--manages to accomplish when it comes to the total package of features and design-constraints.
Including but not limited to:
1. Supports a very large number of individual movements and articulations
2. Meets certain weight-restrictions (overall system must be near-buoyant in water)
3. Supports a wide variety of automatic self-repair techniques, many of which can occur without ceasing operation
4. Is entirely produced and usually maintained by unskilled (unconscious?) labor from common raw materials
5. Contains a comprehensive suite of sensors
6. Not too brittle, flexes to store and release mechanical energy from certain impacts
7. Selectively reinforces itself when strain is detected
8. Has areas for the storage of long-term energy reserves, which double as an impact cushion
9. Houses small fabricators to replenish some of its own operating fluids
10. Subsystems for thermal management (evaporative cooling, automatic micro-activation)
P.S.: Mark my words, nobody is gonna be replace their limbs and torsos in order to shape molten metal or punch asteroids or whatever while paying off the ruinous loan underwritten by by their employer MegaCorp.
Instead you're gonna clock-in to the work office and and plug your mostly-meat-body in to a nice comfy chair, and from there you will control one of the MegaCorp's array of metal-twisting asteroid-punching robots out in the field. MegaCorp knows they are much cheaper to manufacture and insure, easier to repair, and they can be seamlessly tasked to some other worker without messy surgery.
At the end if the day you will log out and hand things off to the next shift, and you can you go home and hug your family without accidentally maiming them.
My old kenpo sensei used to say punching someone in the face is the last thing you want to do in a fight, since you're likely to do more damage to your hand than to your opponent. And most people don't know how to make a fist properly anyway.
On the subject of "what to strike with", I'm reminded of a Terry Pratchett book-quote:
> [The werewolf] gave him a ringing slap and that would have ended it, except that it also pulled itself a little further up the tree and brought itself within the range of the Vimes Elbow.
> It justified the capital letter. It had triumphed in a number of street fights. Vimes had learned early on in his career that the graveyards were full of people who'd read the Marquis of Fantailler. The whole idea of fighting was to stop the other bloke hitting you as soon as possible. It wasn't to earn marks. Vimes had often fought in circumstances where being able to use the hands freely was a luxury, but it was amazing how a well-placed elbow could make a point, possibly assisted by a knee.
-- The Fifth Elephant by Terry Pratchett
A footnote from an earlier reference explains that:
> * The Marquis of Fantailler got into many fights in his youth, most of them as a result of being known as the Marquis of Fantailler, and wrote a set of rules for what he termed ‘the noble art of fisticuffs’, which mostly consisted of a list of places where people weren’t allowed to hit him. Many people were impressed with his work and later stood with noble chest out-thrust and fists balled in a spirit of manly aggression against people who hadn’t read the Marquis’s book but did know how to knock people senseless with a chair.
The classic martial arts trivia (or possibly a teaching) is that serious brain injuries became more common in boxing after padded gloves started being used. Bare knuckle boxing seems more brutal but it's said to have been safer in that regard.
Using padded gloves allows for hitting the opponent much harder without injury to the hand, so they make it possible to hit with a lot more force. Serious brain injury is caused by accelerational forces, and those are only slightly reduced by the padding, but the padding gives significant protection to the thin bones of the hand. Without the protection the bones in the hand could break when struck against the relatively hardy bones of the skull.
Of course if you did happen to nicely hit the jaw, that's one of the common target spots for a knockout. A hit on the jaw causes a rotational force on the head which can more easily lead to a knockout (as well as injury to the brain).
This fact was already discussed during the antiquity.
In the Ancient Greece and then in the Roman Republic and Empire, there were 3 combat sports: wrestling, pugilism (i.e. boxing) and pancratium (i.e. MMA).
Punching was allowed in both pugilism and pancratium, but only the pugilists bandaged their hands with leather straps, to protect them from injuries (analogous to the big boxing gloves and the small MMA gloves of today).
Because of their bandaged hands, the pugilists were using hard strikes to the head much more frequently than the pancratium fighters, so finishing a fight with severe injuries was much more common for pugilists.
Some ancient writers have commented about this and they have mentioned that at big competitions like the Olympic Games it has been decided to schedule the pancratium matches before the pugilism matches, because there were some people who desired to compete in both tournaments. Had pugilism been scheduled the first, there would have been a high risk for them to be injured, preventing them to also compete in pancratium, while with pancratium before, they had good chances to be able to compete in both.
Towards the end of the 19th century, immediately after the opening of Japan, the Westerners learned for the first time about the Japanese martial arts and one of the things that were the most surprising for them was that instead of fighting with fists, like it was preferred especially in USA and UK, the Japanese preferred to use the open hand, preferably the edge or the base, as being much safer and more effective.
At the same time in Okinawa they preferred to use the fists, but that was right for them only because those using fists practiced daily conditionining of the fists by hitting a maki-wara.
Also today, for anyone who does not punch regularly some training device, hitting either with the open hand (edge or base) or only with the external side of the fist (hammer fist) is the right choice for any purpose.
While I am sure there are faked videos out there somewhere I have personally performed multiple non-fake multi-board breaks as have many other people. Generally there is one "trick" though: pencils or small wooden dowels are used to space the boards apart which makes the stack of boards weaker than if they were stacked without spacing. I'd argue this is an allowable aspect of showmanship in that five separated boards is cooler looking than two or three stacked without spacing!
People absolutely can break multiple bricks or boards, without fakery[0]. Or are you referring to specific videos?
[0] "Fakery" including scoring the wood. But multiple breaks usually takes some setup, such as putting small spacers between the pieces of whatever you're breaking. If you consider that fakery, then ... I guess?
i've definitely seen people breaking multiple boards by hand and foot without spacers or scoring the wood, repeatedly, up close, over years. i've done single-board break demos myself. the one piece of 'fakery' they did use was that they broke the wood parallel to its grain, not across the grain, and the individual boards were only ever "one inch" thick (which means less than one inch in the usa due to reasons), even if there was a stack of eight of them
the force required to break a beam is proportional to the square of its thickness, so breaking one two-inch board requires the same force as a stack of four one-inch boards
this was in 01990–01993 and my family didn't own a camcorder; perhaps instead of trying to get your information from videos you should consider consulting an introductory strength of materials textbook
Scoring is absolutely fakery, and sometimes the boards are cut 90% of the way through on the hidden side (evidenced by clean breaks). So are spacers because "breaking X boards" means stacking the boards directly on top of each other, not using the leverage of displacement of breaking each one one at a time.
Ethics > lawyering. If they can't break x boards unqualified, then they can't do it. If they can break x boards specially arranged or modified, sure, but that's called "cheating". It's a gimmick.
Let it be known that according to hi-v-rocknroll's personal code of ethics, it is cheating to break x boards if they are arranged in a specific fashion
Logically, the claim "I can break X boards" evaluates to true if there exists some configuration of X boards which that person can break. They aren't claiming "I can break X boards for all possible configurations of those boards".
No one can break even one board unqualified, because the board could be 20 inches thick and made of lignum vitae. Thus by your definition the phrase "can break a board" becomes useless.
Concrete is more difficult, but there's still a trick to it. The blocks you use for breaking have a bit of flex to them, but are also extremely brittle. So just getting it to flex just a small amount will cause them to break in half. That's also why you place spacers between stacks of bricks or wood. You're leveraging the flex of the material to break it, and stacking them without spacers makes too rigid to break.
In short, this stuff is 90% magic trick.