Tamashiwara-The Physics

Gyakuto

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We all know that breaking boards and bricks is the central, most important part of Karate. This article appeared in New Scientist in the U.K. in the 70s and I actually remember it (with what would now be a bit of an inappropriate cartoon accompanying it!). It’s surprising how much more force concrete requires to be broken, but then that’s why they make skyscrapers out of it rather than timber!

 
It’s surprising how much more force concrete requires to be broken, but then that’s why they make skyscrapers out of it rather than timber!
It's also interesting to note the flip side, how little energy is required to break concrete as compared to wood. Which is why pure concrete would NOT suitable from durability perspective for sky scrapers, it must be reinforced by metal bars.

This is makes the distinction interesting between peak force, and transferred energy in general in strikes and their relative importance. Techniques with peak force might not necessarily be what transfers most energy into the target, depending on what you want.
 
In Marine Corps boot camp, we had two obstacle-based courses. One is called "Obstacle Course" and one is called "Confidence Course." The obstacle course is difficult and it is run over and over again throughout a recruit's boot camp experience. It gets easier, but it's still difficult. The Confidence Course is run twice. Once at the beginning of boot camp and once at the end of boot camp. It's very imposing-looking and the first time through, it's really difficult. At the end of boot camp, it's a breeze, despite still looking very difficult.

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The reason one breaks concrete is because it builds confidence. It isn't a trick, the bricks are not specially treated, there's no cheat to it. They are real 2 inch by 8 inch by 16 inch concrete pavers you buy at a big box home improvement store. But there is technique to it. Once you have the technique, you have it. It doesn't involve muscle or hand conditioning. It's all about using body mechanics and mental discipline.

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n Marine Corps boot camp, we had two obstacle-based courses. One is called "Obstacle Course" and one is called "Confidence Course." The obstacle course is difficult and it is run over and over again throughout a recruit's boot camp experience. It gets easier, but it's still difficult. The Confidence Course is run twice. Once at the beginning of boot camp and once at the end of boot camp. It's very imposing-looking and the first time through, it's really difficult. At the end of boot camp, it's a breeze, despite still looking very difficult.
When I first saw these, I was all too happy. Not only was Uncle Sam giving me three free meals a day, but gave me a playground!
 
When I first saw these, I was all too happy. Not only was Uncle Sam giving me three free meals a day, but gave me a playground!
When we finished the 'slide for life', I was amazed. It was so easy! I wanted to do it again.
 
It is so much fun. I mean, you are getting paid for this! Did you guys do yours over land, water, or both?
Slide for life was a 50 foot tower with a set of cables leading down at a steep angle. You climbed the tower, got on the wire face down and headed down the wire head first. Arm over arm, one leg dangling for balance. That was over land. Then, a third of the way down, you were over water. You would stop, change hands, hang from the wire with both hands, then re-mount the cable with your feet first and your face to the sky. You would proceed down another third of the way. Then you would come to a dead hang again. If your Drill Instructor allowed it, you would once again mount the cable head down and face down and finish the crawl, but more likely, you'd be ordered to come to the position of attention, which would mean you'd fall feet first into the water, shouting "Marine Corps!"

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FYI, I realize that tower is not 50 feet tall. It was in my day, I swear!
 
Slide for life was a 50 foot tower with a set of cables leading down at a steep angle. You climbed the tower, got on the wire face down and headed down the wire head first. Arm over arm, one leg dangling for balance. That was over land. Then, a third of the way down, you were over water. You would stop, change hands, hang from the wire with both hands, then re-mount the cable with your feet first and your face to the sky. You would proceed down another third of the way. Then you would come to a dead hang again. If your Drill Instructor allowed it, you would once again mount the cable head down and face down and finish the crawl, but more likely, you'd be ordered to come to the position of attention, which would mean you'd fall feet first into the water, shouting "Marine Corps!"

190108-M-EH454-0053Y.JPG


160223-M-WQ808-137A.JPG


FYI, I realize that tower is not 50 feet tall. It was in my day, I swear!
I believe you. In Ranger school, we have to do the “log walk, rope drop.” You climb up 50 feet to a log that you have to walk across (less than a boot wide over water at alligator lake). Then climb up 10 feet more to a rope that you have to crawl across to a Ranger sign that you slap. You then receive the command of “hang.” From there, you have to do pull ups (the amount dependent on the impression that you have made on the RI’s) then drop into the water. I was surprised how many people were scared of that obstacle.
 
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