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Related: How do Shaolin monks break spears with their neck?

For anyone unacquainted with the fairly impressive looking feat of breaking bricks (or wood) in martial arts, see THIS 1.5min video. I'd say most people tend to view this practice as impressive, requiring skill and training, etc. Recently, though, I've been wondering if that's really the case.

Are there any analyses of the various factors involved in this feat which suggest that it either is as impressive as it it made to look or isn't?

  • Ability of a "common" man of decent strength to do the same thing
  • Typical mechanical properties of the materials used
    • What types/thickness of wood (pine would be much different than hard maple)
    • Density or type of concrete brick/block material used
  • Force analysis
  • Identification of any mechanical "tricks" (leverage, why spaced apart, etc.)

I'm skeptical, as the materials are always very wide in aspect ratio (thin but long), are always many small pieces vs. a bigger one of equivalent thickness (why break 20 very thin "bricks" when one could break a slab as thick as all put together?), and are always stacked with a space between adjacent blocks.

Question: is the practice of breaking things in martial arts a skilled, impressive feat of strength and ability... or is this far more achievable by the "average Joe" than we're led to think? One other option is that it's primarily an illusion created with some knowledge of force mechanics and material properties.

Additional examples:

  • Break some river stone with a whip of two fingers: LINK
  • Break some thick looking ice: LINK
  • Vid suggesting not just anyone can do this (epic fail): LINK
  • Everything (some brick, then wood): LINK
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Hendy
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    Basic breaking is not hard--good technique, good focus, and follow-through. I've taught people to do a basic front-kick break in two hours from *"no martial arts experience"*. But that is using a strong, tough part of the body on a one-by-twelve plank. Screwing up a break *hurts* and that introduces a real psychological component when you start to move to harder breaks. – dmckee --- ex-moderator kitten Jul 18 '11 at 16:50
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    Additional examples: 1) There's a classic "That's Incredible!" blooper, where Fran Tarkenton tries to clumsily reproduce a martial artist's feat of walking on eggs without breaking them. He intends to fail, for the laughs, but surprises himself when he finds it easy to do. 2) Walking on coals has been reproduced by many skeptics. – Oddthinking Jul 18 '11 at 16:54
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    I've seen kids break boards held by their instructor, but the break was always parallel to the grain, not across it. – Mike Dunlavey Jul 18 '11 at 17:39
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    I saw some martial artists being heckled by someone in the crowd as they would break 2 boards. They challenged him to do the same. they discretely set up the heckler's boards with the grain running at 90-degree angles, making it virtually impossible for him to do so. – fred Jul 18 '11 at 17:50
  • @fred (+1): That reminds me of a scene from the movie "Big Trouble in Little China" where Jack chooses which bottle will be used in a bet that his pal made to break a bottle in a certain way. The heckler should have demanded almost the same thing: "_Not that board, this one..._" and selected one of the boards from the "to be broken" pile. =) – Randolf Richardson Jul 18 '11 at 18:51
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    @Oddthinking Nice examples, they are quite different from breaking a brick through concentration, though. I have no qualms of walking over coals or sitting down on a bed of nails without ever having tried to – because I’m confident in my basic understanding of physics and physiology. I *do* have these qualms about breaking a brick, or throwing a needle through a glass pane. – Konrad Rudolph Jul 18 '11 at 19:30
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    @Randolf: With two boards setting the grain perpendicular when you stack them makes it much, much harder. So this is a dirty trick. And if you are using a linear sticking surface (knife edge of the palm, or a edge-on side kick) getting lined up with the grain is part of the technique. – dmckee --- ex-moderator kitten Jul 18 '11 at 19:31
  • Sorry to seem off-topic but one of the similar videos was this and I couldn't help but post it! http://www.youtube.com/watch?v=joQ1cJKNSWo&NR=1 – Freesnöw Jul 18 '11 at 22:57
  • @Konrad: Breaking a brick is a matter of force. For that matter, throwing a needle through a glass pane is a matter of force, although there are physiological limits on how hard you can throw something (see Major League Baseball for examples). – David Thornley Jul 19 '11 at 01:52
  • @Hendy: What would you define as an impressive feat of strength and agility? – David Thornley Jul 19 '11 at 01:59
  • @David Whether it’s a matter of force or technique (or, most likely, a combination) it’s something that has to be acquired. Walking over coals needs no skill whatsoever, except for a brisk stride. – Konrad Rudolph Jul 19 '11 at 07:11
  • @David Thornley: Good question! Perhaps, could I put on a glove and punch through a couple of bricks right now? Mainly, is it mostly show when they do the three practice slow punches that make it look like there is a ton of "art" going into this? Or is there any significant mastery of anything required to do this. Sounds like the main thing is hand/skin/bone toughtening, but that it's not nearly as woo-ish as it's made to look. Does that help any? – Hendy Jul 19 '11 at 13:09
  • A little of both. Technique matter as it is important to (1) hit the center of the target region, (2) hit it with the right part of the striking surface and the correct alignment (Ever let your wrist collapse when hitting a punching bag? Now imagine you're hitting something even harder...) and (3) get good follow through, but the "practice" strikes are a also chance to let the judges or audience see your *"emotional intensity"*. I usually only make two slow-mo passes, but other people like more. – dmckee --- ex-moderator kitten Jul 19 '11 at 17:43
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    In my experience (TKD red belt), breaking is not as physically difficult as one might imagine, but it it mentally harder than one might imagine because it requires you to commit yourself to the strike. You _know_ you will be injured if you do it improperly. Physical toughening of your skin, muscles, and supposedly even bone isn't really important until you're getting into pretty hardcore breaks. The average fit person could break a paver with the heel of their hand without physical toughening, if they could do the strike with proper form and speed. – Larry OBrien Dec 31 '11 at 23:45
  • @Larry OBrien: either it is physically easy to break (under certain fixed conditions) or it is not. Focus is totally irrelevant, as it will not change the laws of physics. – nico Jan 01 '12 at 10:01
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    @Nico You are wrong to discount mental difficulty as an impediment to physical accomplishment. Just as an untrained person is unlikely to move as quickly along a ledge high above the ground as one 6" above the ground, perform a movie stunt without flinching, or recite poetry while standing on a median lane, an untrained person is unlikely to be able to develop speed (loose oppositional muscles) and throw all of their weight behind their fist if they know that avoiding injury requires their knuckles, wrist, and arm being aligned quite well and only being tensed into that alignment very late. – Larry OBrien Jan 02 '12 at 01:58
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    @nico: It's an athletic endeavor like any other, and once you get away from the basics, "focus" or "concentration" or whatever you want to call it *does* matter. Just like it does in gymnastics or tennis or golf or any other sport where coordination and form are important. – dmckee --- ex-moderator kitten Jan 02 '12 at 04:42
  • @LarryOBrien and dmckee: no, this is a question of phyics. Psychology may be important to actually convince someone to do it, but it will NOT change the laws of physics. If it is impossible for a human being to break a 10cm thick tablet of steel with his hand it will be impossible no matter how hard he tries. The question here is purely physics: can you break a tablet of a defined material/thickness/orientation/etc. by applying a force equal to the one of which an average human being is able to create with his arm? Physics, not psychology. – nico Jan 02 '12 at 09:58
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    @nico: I am quite sure that [dmckee](http://physics.stackexchange.com/users/520/dmckee) is aware of the physics. – Sklivvz Jan 02 '12 at 20:06
  • @Sklivvz: I never say he wasn't. But you do not need to be a physicist to understand that this is an -albeit complex- physics problem. No more no less. – nico Jan 02 '12 at 20:40
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    @nico I don't see anyone claiming that the laws of physics yield to mental aspects. – Larry OBrien Jan 02 '12 at 21:38
  • My old karate instructor told us of a demonstration he watched. The "breaker" built the tension by adopting a stance and very slowly lifting his foot and then lowering it onto the tiles, easing into the necessary focus. Then he reset his stance and repeated the motion. And reset his stance and repeated the motion again - but this time as he very gently rested his foot on the stack of tiles he accidentally broke the first two. Woo-oops! :-) – Grimm The Opiner Oct 22 '13 at 10:04
  • TKD 2nd degree black belt here (it's in the US but run by Koreans, so judge it as you like). Breaking boards isn't really all that difficult; it's more like icing on the cake. You see the martial artist do a really cool kick, and it ends with a satisfying "snap" of the board breaking. When we perform in local schools, we use little firecrackers on the boards for the very reason. – user3932000 Jun 03 '15 at 02:31
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    However, I do agree with @LarryOBrien that there's a mental aspect to it. Although it's not super difficult, the fact of the matter is that you're still hitting your body against wood (or stone), and it still hurts if you do it wrong. And the chances are that an "average Joe" can probably break through a wooden board no problem, but he'll walk away with his hand hurting like hell. – user3932000 Jun 03 '15 at 02:36

1 Answers1

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Cecil Adams of the Straight Dope is a noted skeptic and debunker of myths, and was asked about this one

He read a paper:

"The Physics of Karate Strikes" by Jon Chananie at the University of Virginia.

that in turn cited physicist Jearl Walker - probably section 1.45 of his book The Flying Circle of Physics.

He then anecdotally describes using this knowledge (and other research) to give it a go, and in his first session was splitting 5 boards. A younger assistant could split 3.

As Cecil Adams is not a martial artist, it seems that the skill is more about knowing how than concentration or special strength.

Oddthinking
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