Bamboo and human bone

Spartacus Maximus · Black Belt

Has anyone ever heard of bamboo being similar to human bones for density or hardness, flexibility or other characteristics that are comparable? Have you heard of other material that have been used to build training tools specifically because they are good stand-ins for human body parts?

Weapons such as swords are commonly tested with various materials, but it appears to be less common with empty handed systems. What materials have you heard of being used in the system you practise? Is it something of the past or are these still used despite the availabilty of modern equipment?

Wastelander · KF Sensei

As I understand it, bamboo of a certain size is roughly as difficult to cut as bone, but people often mistake that for being the same as breaking a bone. I believe Mythbusters worked out a certain diameter of poplar dowel broke at the same point as bone. Bone is a rather hard thing to emulate, it would seem
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Tempest · Green Belt

Spartacus Maximus · Black Belt

The evidence does indeed show that breaking a bone and cutting through it require two different types of force. A bladed weapon such as a sword can concentrate much more force in its sharp edges than any kind of impact from a strike with hands, feet or legs.

The most important factor to consider when trying to find something suitable to simulate bone is the fact that living bone is much more flexible than dead bone, as well as being wrapped in muscle and other soft tissue, which varies depending on each person.

Many martial arts systems from Okinawa and Japan use standard wooden baseball bat handles for breaking. Although the point is probably not to simulate a bone of the same size, could this practise provide any accurate information about what is required to break a bone? What about wrapping the bat handle, dowel etc in a layer of foam or other materials to simulate tissue/muscle?

Tempest · Green Belt

With regards to BREAKING a bone, I would suggest trying this:
Get a poplar or ash dowel rod of approximately the thickness of the bone you are trying to simulate, then get about a %15-20 ballistics gel to form the flesh surface, form it to about the thickness you want of flesh of the dowel rod and try hitting it. I warn you that at first this will not be pleasant, as striking %20 ballistics gel with your bare hands is not fun, but it wont HURT you per say, just mess up your form.
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sensei8 · KF Sensei

I've trained with bamboo within specific interests, for quite a long time, in which I've found bamboo to range from intense to boring. The newer the bamboo, the tougher it is to break, whereas, the older the bamboo, the easier it is to break.

And let us not forget that bamboo, when being broken, can, and will, cut you to shreds, especially with any penetrating technique, with is pretty much every MA technique(s).

The old the bamboo, the more one has to bind together to increase its density because, as I've already mentioned, bamboo loses its density; it becomes brittle compared to "green" bamboo. Old bamboo has a hue of "tan" to it.

On last note, a fun note, bamboo makes a really cool sound effect when it's broken...I love that sound...I'm easily amused!!

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DWx · Black Belt

Are we talking breaking a human bone empty handed or slicing with a weapon. And I assume you mean impact across the width and not along the stem. Bamboo is actually both really strong (excellent tensile strength and compressive strength) but is also flexible allowing it to grow tall but thin and move in the wind. That's why it is used as a building tool in tropical climates.

One of the comparisons I've heard before was that a standard 1" pine board was comparable in strength to a rib. Not sure how true that is? One of the parents at our club also took a set of rebreakable boards to work once (he's an engineer) and measured the impact force required to break each. I'll see if I can find what I did with the info.
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Spartacus Maximus · Black Belt

Well, as most posters mainly practise empty handed systems the original question was intended to be about breaking bones by striking. The result of impacts from one limb. For example, breaking an arm bone (cubitus or radius) or a lower leg bone (tibia or fibula).

JR 137 · Black Belt

One flaw I always find in these "it takes the same amount of force to break a rib as it does to break a single pine board" type analogies is this...

Humans move. They have quite a bit of give. Ribs compress, the defender braces for impact thereby spreading out and slowing down the force, etc. Hitting a pine board that's fixed/locked into place such as on top of concrete blocks will break easily. A pine board on top of a pillow? No so easy. A coconut on the ground will smash far easier that one that swings on a rope. If you equate a coconut with a skull, a coconut attached to a neck is going to be far harder to break that a coconut that can't move and disperse that force.

If I have all my weight on one leg and don't see a kick coming, my tibia will break far easier than if I lift my leg and allow someone to kick my shin with the same amount of force and pressure at the same exact location.

Using arbitrary force amounts, if it takes 100 Newtons of force to break a "fixed" tibia (doesn't allow any movement), it'll take multiples of that to break my tibia in actual fighting where I can move, fall, etc. It's the same concept as throwing an egg against a wall vs against a bed sheet. And that doesn't take living bone vs dead and dried up bone into account.

Tempest · Green Belt

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