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Karate punching is like swimming...

Posted Jun 28 2013 7:32am

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How many times has your sensei told you that the power of your punch should originate from the ground? That you draw power from the ground and then transmit it up your legs, through the hips and torso and down your arm. You believe him/her because you respect them, they have years more experience than you and they can punch harder than you (and you should believe them because it’s basically true) but you can’t quite get your head around why it should be true.

Drawing power from the ground gives karate a mystical, magical quality as if Mother Nature herself is giving you some ‘power assist’. If, like me, you tend to prefer more rational explanations then it’s easy to think that drawing energy from the ground sounds like twaddle.  But it isn't twaddle; it can be explained by the laws of physics.

I have recently been privileged to have a sneak preview of  John Cole’s excellent book chapter on forces called ‘Push and pull explains all techniques’. I don’t want to pre-empt anything John has to say on this topic before his book is published but suffice to say he mentions Newton’s third law of motion which states: Every action has an equal and opposite reaction.  If we apply this law to people then basically, when you apply a force to an object it responds by applying and equal amount of force back to you. You transmit some of your energy into the object (e.g. by pushing it), the object transmits an equal amount of energy back into you.  What happens to that energy once it comes back to you depends on several factors: if you happen to be the smaller, lighter object then you will probably move; if you are not able to move freely, you’re restrained in some way, or the returned energy is being transmitted to a small surface area (e.g. you pricked your finger on a needle) then the energy may cause injury to you instead or alternatively you may be able to utilise the returned energy in some other way.

In my title I said that karate punching is like swimming. More specifically ‘drawing energy from the ground’ is analogous to pushing yourself away from the side of the swimming pool to gain momentum. If you can swim then you will know from experience that it is quicker to get some speed up if you push yourself away from the side of the pool with your feet than to just start swimming from a standing start. Why is this? Newton’s third law of motion explains it… push against the wall of the pool, transmitting energy into it and the pool wall ‘pushes’ an equal amount of energy back to you in the opposite direction. Since you are in a horizontal position in the pool (and you are weightless in water) the effect of receiving the energy back is to propel you in a forward direction.

A karate punch works on the same principle. If you take a firm stance and push down into the ground with your feet, transmitting energy into it, the ground responds by pushing an equal amount of energy back into you. Since you are in a vertical position the energy is transmitted upwards (opposite to the direction you pushed in). Though you are lighter than the ground below you the effects of gravity pressing down on you make it unlikely that you will respond by launching upwards (unless the ground below you was a trampoline!) The received energy doesn't normally injure you either because it is spread over the relatively large surface area of your feet (It might hurt more if you just pushed the ground with the top of your big toe) Instead, you are in a position to utilise that returning energy to enhance your punch.  How you achieve that is worthy of a blog or two of its own; suffice to say that with the correct sequence of muscular contraction and relaxation, starting with the lower legs, upper legs, hips, torso, shoulders and finally the arm and fist the energy can be transferred from muscle group to muscle group until it finally leaves your fist!

This won’t happen by chance though – only through training and practice can you learn to utilise the energy that you received via Newton’s third law of motion by pushing into the ground first. Without training this energy will just dissipate from your feet or half way up your legs and be wasted.  The harder you push into the ground the more energy you’ll get back (the harder you throw a ball at a wall the further and faster it comes back to you; the harder you push off the pool side the further and faster you’ll glide through the water).  Punching is only different because we are complex beings and we have to train to learn how to utilise that energy effectively.

The point of this blog post was not to explain the whole physics of punching but to give the scientific explanation (in layman’s terms) of why sensei is right when he says you must draw your punching power from the ground.  Do I make sense?

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