How Board Breaking Works

Say a person has been training in a martial arts technique for some time and is reaching a level of high proficiency. We'll call her Jane. Say Jane leaves the training studio one day after practice and heads home. But when she turns a corner, a bunch of thugs jump her.

Thanks to her training, Jane's muscles react instinctively before she has time to be scared. She twists out of the grasp of Thug 1 and spins, landing a devastating kick on the side of his knee, which bends inward with a sickening crunch as he collapses. Thug 2 charges. Instead of running, Jane engages, closing the distance between them as she slips sideways and up, redirecting his attack with her shoulder and simultaneously breaking his nose with her elbow.

Thug 1 can't walk and Thug 2 is on the ground covered in the blood gushing from his nose. Both are screaming with pain. As Jane stands over her vanquished foes, adrenaline surging through her, she hears applause. Her teacher emerges from the shadows and confers a black belt on her as other students cart away the bloodied and broken "thugs."

Needless to say, the above is total fiction. Yet, the scenario described is exactly the sort of thing martial arts training is designed to help people face, and staging an unexpected attack on a student would, in some ways, be an ideal way to test her level of competence. However, as we can see, such a testing methodology has some inherent flaws (e.g., potential long-term damage to body parts). Aside from liability issues, it might be hard to find "thugs" willing to sign up for a certain mangling. And, of course, it's always possible a student will crack under real-world testing and end up maimed or worse — not exactly the kind of publicity a dojo wants.

To avoid such scenarios, a number of the martial arts developed a testing regime that includes board-breaking. Seen in this light, it makes perfect sense. Instead of hurting somebody else, hurt some lumber!

When training a beginner to break a board, a teacher focuses on helping his students to conquer their instinctive aversion to self-inflicted harm. Whacking a board as hard as we can with our bare hands just doesn't come naturally. And our fear of hurting ourselves in doing so is entirely justified. To break a board without breaking your hand, you have to do it just right, focusing your energy and hitting with enough force and follow-through (more on this later). Luckily, it turns out that even the tiny bones in your hand can handle a lot of stress — 40 times more than concrete, believe it or not [source: Newton's Apple].

Once students have mastered this initial phase, they can move on to the intermediate level in which they begin to increase the quantity of stuff they can break. The more they're expected to break, the more force and focus they require to accomplish their goal. Teachers must be vigilant during this phase as overconfident students can really injure their hands.

From there it's a matter of students continuing to train their energy and focus until they can break a giant stack of concrete blocks with a single blow. That's not a joke. People actually do that. In fact, board-breaking has taken on a life of its own, and there are now international competitions where adepts demonstrate astounding feats of concentration and power [source: Serrano].

But how do they do it?

Picture this: A man stands on a platform above a stack of seven massive slabs of ice, each one weighing nearly 300 pounds (136 kilograms). Putting his hands behind his head, he suddenly bends his upper body down to the top slab and touches it with his forehead. He repeats this process several times until, on the last bend, he follows through and hammers his skull into the slab. Incredibly, all seven blocks of ice break in half and fall to the ground.

This really happened. Strongman J.D. Anderson, aka the Iceman, smashed 2,000 pounds (907 kilograms) of ice to pieces with his head on "The Tonight Show with Jay Leno." That's extreme, and not recommended (see How Chronic Traumatic Encephalopathy Works), but it demonstrates how phenomenally powerful the body can become given training and focus.

Breaking boards with your bare hand is a simpler feat than the one described above, and less potentially injurious (although your hand is a precious thing, too, and should be treated accordingly — more on that later). Typically, beginners start with a single board, roughly 1 foot (30 centimeters) wide. The material is usually pine, which is a softwood that breaks much more easily than a resilient hardwood like oak. The board should also be free of knots.

There are a wide range of techniques students can use, such as "hammer fist" (bringing your clenched fist down), "palm heel" (striking with the heel of your palm) and "knife hand" (the good old karate chop). Someone can hold the board, or it can be placed on supports. It should be held or supported on the sides, rather than the ends, allowing the practitioner to break the wood along its grain. Going against the grain, as the expression suggests, is much more difficult.

Regardless of what technique a practitioner uses to break a board, instructors usually emphasize preparedness through practice. Hitting a padded surface repeatedly helps increase accuracy, speed and strength while also toughening up the striking area of the hand or foot.

Mental preparation is as important as physical in this case. Hitting anything accurately requires focus. Practitioners work on their focus through breathing techniques, such as breathing out sharply or even shouting as they strike.

And when breaking a board, it's important to hit it as close to the center as possible. One of the key mental limitations that must be overcome is the body's natural instinct to slow down when approaching hard surfaces in order to avoid injury. Paradoxically, if your hand or foot slows down before hitting the board, the wood won't break, and if it doesn't break, the force of your blow will rebound into your hand and injure it. For this reason, instructors get their students to focus on hitting, not the board's surface, but a point a few inches beyond it. Imagining this point helps prevent the instinctive slow-down and ensures follow-through, which in turn helps transfer the full force of the blow to the board, breaking the wood instead of your hand or foot [source: American Martial Arts Academy].

That's all very well, but technique doesn't really explain how it's actually possible to smash apart hard objects with your soft, pliable extremities.

What exactly is a newton? No, not the tasty cookielike treat, but the unit of force. A newton, to be precise, is the amount of force it takes to shift a kilogram of stuff one meter [source: Merriam-Webster]. This also turns out to be roughly the same amount of force with which that celebrated apple supposedly clonked Isaac Newton on the head, inspiring his discovery of gravity. Coincidence? So they say. But that's a different story. The reason we're talking about the newton is because it's a useful way of measuring the force needed to break things like boards.

Back in the '70s, a couple of physicist martial artists decided to apply one of their passions to the other and did some research on board-breaking. How is it, they wondered, that we can lord over hard lumber with our puny hands and feet? Our big advantage, the thing we've got that that inanimate matter doesn't, is speed. And if we circle back to good old Newton (Isaac, not the cookielike treat or the unit of measurement), we might remember from our high school physics class that force equals mass times velocity. In other words, the faster you throw a punch, the harder it hits. But how much speed do you need?

The physicists found that a typical beginning practitioner of karate can work up a hand speed of 20 feet (6 meters) per second, which is just enough to break through a standard 1-inch (2.5-centimeter) piece of pine (students sometimes use reusable plastic training boards that are roughly the same dimensions and designed to break under the same amount of stress).

One of the physicists, Ron McNair (who later died aboard the space shuttle Challenger) was a black belt. It turned out he could get his karate chop going up to 46 feet (14 meters) per second, which means he could hit stuff with 2,800 newtons of force. If that doesn't sound impressive, consider this: It only takes 1,900 newtons to break a 1.5-inch (4-centimeter) thick concrete slab.

As mentioned on the previous page, speed isn't enough. Even speed and accuracy together aren't enough. Follow-through is crucial. And it's not just because we tend slow down out of fear of self-injury, it's because we tend to slow down no matter what. The reason for this was fathomed by yet another physicist martial artist who discovered that your hand reaches its top speed when it's 80 percent of the way through its strike. That's another reason why it's so important to aim your blow beyond the surface of the board.

Once a hand or foot makes contact with the board in just the right spot and with the necessary speed, the wood, like all material, will begin to oscillate until it just can't take it anymore. When material can't take any more oscillation, that means its elastic limits have been breached. Limits breached, with a loud sigh (snap), it surrenders (breaks) [source: Rist].

Thus, board-breaking is accomplished. But here's the big, looming question: Why do it? We learned earlier that proponents believe board-breaking is a useful gauge of progress, but is that really true? Is smashing lumber to pieces really a good idea?

One ostensible reason for the promotion of board-breaking as an aspect of martial arts training is that it allows instructors to evaluate students' progress in a safe, controlled manner rather than throwing them into the ring with an opponent. But not everyone agrees with this. In fact, some instructors are vehemently opposed to board-breaking for a whole range of reasons.

One argument is that it's dangerous, especially for children. The human hand is an incredibly complex body part with 27 small bones, which allow for astonishing dexterity. Capable of phenomenally complex tasks like playing a violin, performing open-heart surgery or knitting miniature sweaters, the hand, skeptics argue, is not something we should fling repeatedly against hard objects. It's a body part we should safeguard for the future.

Breaking boards is hardly risk-free. Opponents point to cases in which young martial arts students have broken carpals, metacarpals and proximal phalanges (palm and finger bones). Should we really risk the hands of future musicians, truck drivers, doctors, sculptors or journalists?

Another objection to board-breaking (which often starts at the beginner level) is that it teaches children an unfortunate lesson: namely that performing meaningless stunts is praiseworthy. Ultimately, they say, board-breaking is useless in the real world. As the legendary Bruce Lee is supposed to have said, "Boards don't hit back." The point of martial arts isn't to be able to bust up a stack of pine, it's to be able to defend yourself from physical assault. To achieve that end, students should focus on enhancing their agility, speed, conditioning and technique.

Board-breaking skeptics argue that the real reason martial arts instructors like to use board-breaking isn't as a gauge of progress but rather as a visually impressive promotional stunt to attract more students [source: Salick].

No doubt some of these objections are valid. But the most compelling argument, that board-breaking is injurious, is hard to prove. While it's difficult to find statistics specifically related to board-breaking, numerous studies have been conducted on the safety of martial arts training. They all seem to indicate that while some practitioners do get hurt sometimes, the bulk of the injuries are minor bruises and cuts. Martial arts, according to the studies, are relatively safe, particularly karate [source: Zetaruk]. And since tameshiwari is such a common feature of karate training, it seems probable that breaking boards is pretty safe, too — as long as you practice and prepare.