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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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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 Jul 18 '11 at 16:50
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
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
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
@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 Jul 18 '11 at 19:31
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2 Answers

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.

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The fun part comes in doing correctly and with good follow through the time after you've failed. –  dmckee Jan 2 '12 at 4:44
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It is true that breaking a board or brick or tile is a matter of physics. But the human hand or foot is not the same as a hammer or axe. It is softer and pliable and prone to injury. There are things we can break and those we cannot. Mass X acceleration is the formula. The faster the tool(hand or foot or fingertip) the more force produced.

Psychology also plays a part in the way of belief or confidence.It is not a natural action to hurl a sensitive part of one's anatomy at a hard and unforgiving surface. When the practioner is afraid, they will subconciously hold back at the critical moment thus slowing the attacking tool and lessening the force so mental focus is essential. Also, if the technique is innaccurate then it will also fail. If the wrong part of the tool is produced, then the technique will fail. When the practitioner fails to produce enough force to break the target,they are usually still producing enough force to DAMAGE the tool(hand, foot etc). Failure can lead to broken appendages which of course hurts enormously. It is possible to be psyched out so there is merit it whatever ritual, practice move, slow breathing etc that the practitioner chooses to use. The traditional shout or KIAI does aid the practitioner in committing heart and soul to the action.In the uk, the very respected TV programme"HORIZON" wanted to explore this very issue. I believe it was during the eighties that they approached various martial artists and settled on the now Grand Master Rhee Ki Ha OCM 9th Dan Taekwon-Do Master. At the time I believe he was a seventh dan.He was chosen because he could CONSISTENTLY perform, time after time, for the camera. I don't know if this archive is accesible, but you shoud try to find it. I seem to remember the title of the article was "MOVING STILLS". High speed photography was used with proper scientific conditions. The program makers discovered that the human body tool use to impact the target actually acted as a liquid at the point of impact, thus avoiding injury even though the target would be destroyed. Further research was inspired. ITF style Taekwon-do teaches breaking to it's students as a matter of course from the outset of the students training. They have never waited till the student reaches a high rank before starting them on breaking. In Taekwon-do, breaking is taught as a test for the power and accurracy of the technique. you can't perform at full power on an opponent , you would break the opponent and end up with no mates. Search up Grand Master Rhee. He is a veteran of power breaking and even now in his seventies, he still smashes bricks to smithereens.

For my part I am a 4th Dan black belt in the art of Taekwon-do and a former World and European champion (1984). I am now a middle aged lady but I still teach and my students learn to break as soon as they can perform the technique, whether they have trained for an hour, month or year, if they follow my instruction exactly, they succeed. There is no mystery, but there is definately a special method which needs to be taught correctly. In the case of breaking large amounts of boards, bricks etc, then body conditioning and sheer practice are essential. Please note, that is CORRECT practice. I can't afford to treat students in a cavalier way. they trust me not to lead them to injury. I've NEVER caused student to damage themselves- EVER. But it can happen.

So after all that, yes it is just physics within the limits of the materials used, ie; human flesh versus really hard strong stuff. BUT it is also psychological conditioning. Make no mistake, you must master youself before you master the target and that just takes as long as it takes--

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Welcome To Skeptics!. Here we require all answers to cite sources for their claims. Please include references to reliable sources (scientific papers, official documents of reliable organisations, articles by experts, etc etc) for your claims. It is also preferred that you quote key passages from your sources, this makes your answer more readable (something which it sorely needs), and protects it against link-death. –  Ian May 22 '13 at 10:08
"Mass X acceleration is the formula." That is, of course, Newtown's Second Law, but I don't think it is the relevant formula. As you teach the technique, I am sure you are concerned about the direction of the grain. This wouldn't matter if it was merely magnitude of the force. For another example, scalpels can cut into wood even if they are relatively light and are moved slowly. –  Oddthinking May 22 '13 at 15:03
yes , but they don't break it and they don't cut very far. I did say 'within the limits of the materials used' and of course the directiion of the grain is important as is where abouts on the board the tool impacts. I don't want to get into an obsessive argument about this to the nth degree.I believe I answered the question which was whether or not the destruction of a board , brick or etc was an impressive act requiring certain qualities or whether it was something anyone could do if they felt like it. –  Deborah Herries May 23 '13 at 3:19
Ian, thankyou for your welcome. I answered using knowledge gained from personal experience of teaching and of learning from Master Rhee Ki Ha. Most of the science is explained in theITF Taekwon-Do Encyclopedia by General Choi Hong Hi, the founder of Taekwon-do. The other clear reference is to the television programme I mentioned in my answer.I'm sure that there are many out there who can make obscure quotes but I wasn't aware that this had to be a thesis type essay. What is link death? –  Deborah Herries May 23 '13 at 3:26
@Deborah sorry for not replying sooner. You can alert users to your comment by writing "@username". Skeptics is a part of the Stack Exchange network, a goal of stackexchange is to be a one-stop information source. i.e someone could come here with nothing but a question and an internet connection and find answers. Thus we like sources to be linked to directly (it's unlikely that most visitors will have a copy of the "ITF Taekwon-Do Encyclopedia"), however links can die (e.g the target website goes offline), so if you include quotations of key points then they will survive. –  Ian May 29 '13 at 11:51
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