Kicking question

terryl965

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Does the speed of a kick directly impact the damage to the person or is it the power of the impact that damages the person. I have always been a believer that speed is grater power behind any impact but another instructor said he believe power is best even if it is slower before impact. Any thought would be appreciated.
 

dancingalone

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I have always been a believer that speed is grater power behind any impact but another instructor said he believe power is best even if it is slower before impact.

Speed is a component to creation of force, so I am uncertain what this guy is saying. In general, you want your kicks to be as fast as possible as long as you can also bring your usable mass to bear at the same time.
 

FearlessFreep

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Different applications.

A sidekick can push someone away if it has more thrust than speed, or it can burst a spleen and leave the guy standing, if it has more speed than power, relatively. That's why we have speed breaks and power breaks.

But which you want at a given time depends on what you want to accomplish.

We were practicing a technique the other day and part of the technique was a palm-heel to the face. However, because of the nature of the technique and the situation, what we did *not* want to do was to push the guy back. So the strike had to be very fast but not very deep.

Similarly, you may be in a situation where you want to push your opponent back to make space, or you may want to hit them hard but keep them in. They are both powerful, but they have different goals and cause *different* kinds of damage
 

dancingalone

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Good point, Jay, but I'm not sure that the original question was. "Does the speed of a kick directly impact the damage to the person or is it the power of the impact that damages the person."

Pushing type techniques generally don't damage the opponent unless they have a joint trapped in an unbendable state or if they are driven against something hard that damages or makes them fall.
 

StudentCarl

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A couple of thoughts:

1. Same mass and speed into a smaller area increases the force. Hitting with whole sole of the foot doesn't concentrate force like hitting with heel only.
2. Mass at the point of impact depends on technique. Kick with just leg has less mass than one you get your body mass into the foot or fist.
3. I think what you're calling "impact" is the same as force at contact. So yes, mass and speed are the keys. The physics are F=MA (Force = Mass x Acceleration). Since you don't change the mass of your foot, speed is what you control. However, weapons of greater mass change the equation: kicks have more mass than punches, so they're inherently more forceful/powerful.
4. Target selection is the hidden but, IMO, most important variable. I've trained a fair amount with firearms, pistols in particular. The decisive variable in handgun stopping power is bullet placement. It doesn't take board-breaking force against soft targets like the throat. And I've taken some amazing round kicks in the butt (sparring partners with poor skills)--left me sore but undamaged.

The simple answer is that your foot's mass doesn't change, so yes, speed is what affects power. Would you rather try to break a board with a slow kick or a fast one?
 

ATC

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What makes power - Speed + weight togeather with relaxsation and consentration is what makes power.

So I am not sure how you have power without speed. You can have a big guy hit you hard but if he hits you faster with the same impact then the power increases.

Hitting fast but disconnecting your technique before full impact will decrease your power but then you are not hitting. You are simply getting to the target as fast as you can and then stopping. You are not letting the target absorb the energy, but rather using more energy from yourself to stop the technique.
 

zDom

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http://www.howeverythingworks.org/journal/Article1.1.pdf

My understanding, based on physics classes in the past and refreshed by the above scholarly paper, is:

when you wanna damage something with a strike, speed is more important than mass.




What makes power - Speed + weight togeather with relaxsation and consentration is what makes power.


"Power" may not be a good term to use in a discussion of the physics of striking.

I mean, a bulldozer, for example, would have more power than a guy pedaling a 10-speed bicycle. But I would rather be pushed by a bulldozer moving 1 mph than a 10-speed that is going 50 mph.

I understand, I think, what you are saying and if so you are correct:

In striking, relaxing enables you to get more speed, which results in putting more destructive force into the target.

By concentration, do you mean, thinking hard about where to correctly put the strike? (i.e., deep enough INTO the target to deliver the force) or in concentrating that force into a very small weapon, i.e., just two knuckles?

Both, I agree, are important.
 

Earl Weiss

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A couple of thoughts:

1. Same mass and speed into a smaller area increases the force. Hitting with whole sole of the foot doesn't concentrate force like hitting with heel only.
2. Mass at the point of impact depends on technique. Kick with just leg has less mass than one you get your body mass into the foot or fist.
3. I think what you're calling "impact" is the same as force at contact. So yes, mass and speed are the keys. The physics are F=MA (Force = Mass x Acceleration). Since you don't change the mass of your foot, speed is what you control. However, weapons of greater mass change the equation: kicks have more mass than punches, so they're inherently more forceful/powerful.
4. Target selection is the hidden but, IMO, most important variable. I've trained a fair amount with firearms, pistols in particular. The decisive variable in handgun stopping power is bullet placement. It doesn't take board-breaking force against soft targets like the throat. And I've taken some amazing round kicks in the butt (sparring partners with poor skills)--left me sore but undamaged.

The simple answer is that your foot's mass doesn't change, so yes, speed is what affects power. Would you rather try to break a board with a slow kick or a fast one?

I agree with most of this and perhaps it is just an issue of semantics, and a question of simple physics not translating well into th complicated machine that is the human body.

While the mass of your foot / hand does not change, you can change the amount of mass that is employed while delivering the hand or foot technique. Think of a backfist strike. Jsut Flick the hand out as quickly as possible using only your arm motion and you use litle mass. Now, use your legs, torso and hips to generate the Backfist and it may be no faster but certainly more powerful.

Another example would be coordianting the kick or strike while moving the entire body in the direction of the target.
 

ATC

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Impact power is what is needed. Since we all agree that power comes in many forms, the proper or form we are looking at is impact power. How much force is transfered into the target at the moment of impact.

A 100 pound object moving at 1 mile an hour will not have the same impact as the same 100 pound object moving at 100 miles an hour.

So the speed of the object is what determines the force or power.

toss a bullet at someone and they will not be hurt at all by it. Fire that same bullet out of a gun and it will destroy the same object by passing through it.

Speed added to any object will increase its impact power. It really is just that simple.
 
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FearlessFreep

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toss a bullet at someone and they will not be hurt at all by it. Fire that same bullet out of a gun and it will destroy the same object by passing through it.

Mount that bullet as the hood ornament on a semi and drive it through a brick wall at two miles an hour. That's a different kind of power, but not one to be overlooked
 

ATC

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Mount that bullet as the hood ornament on a semi and drive it through a brick wall at two miles an hour. That's a different kind of power, but not one to be overlooked
The bullet has nothing to do with the impact power in your case. You simply changed/increased the mass of the moving object. Increase the speed of that same mass from 2 mile an hour to 100 miles an hour and your impact power still increases. There is no getting around the physics.

If I fire a metal softball out of a howitzer at the same semi, the semi will be destroyed. All I needed to do is speed up that metal softball. You can't have impact power without speed. A semi at 2 mile an hour would have more impact power than the same semi at 1 mile an hour. The discriminating factor is the speed. Yes the mass matters too but if you cannot increase your mass you can only control the speed of your mass.
 

Manny

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Well I think that's why we have snap kicks and trusting kicks in MA. I once caught a fellow student with a well placed snap roundhouse kick to the solar plexus and he almost collapse, I remeber he could not brethe very well and it was just a snap kick, this made me believe that a kick with much force will at least collapse and or a broken ribs would be take place.

Yes speed is good cause you can caught your oponente offguard, like the last examination were a roundhose kick just slaped on my chin, if this kick would have more foce maybe a well knock out will be take place.

So what is better speed or force i will say a combination of both.
Manny
 

Touch Of Death

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Just my 2 cents, but I think part of your kicking power should result from the larger circle of stepping through as well as using the smaller circle of the snap kick itself. After you center your mass behind a kick, you must allow your body to slowly but surely pass the point of no return, or as some would say, you must have good rotation. Secondly, conditioning and allowing your muscles to cock and fire a kick, at high speeds, will maximize the effectivness of a basic step through. So, training to kick and plant back is not the most effective way to develop power, kicks are most powerfull when your whole mass is rotated through in the process.
Sean
 

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