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charliedw
charliedw's picture
Generating Impact

Hi all. I'd like to submit this for your consideration.  Challenging the conventional wisdom a bit on generating impact, but I hope you find it thoughtful and interesting!

http://bunkaijutsu.com/2018/07/how-to-create-more-impact-in-a-martial-arts-technique/

Regards

Charlie

Dennis Krawec
Dennis Krawec's picture

Not so unconventional as you might think. 

Boxers use different power(force) generation techniques depending on the punch they are throwing. For example a Cross in boxing (reverse punch) tends to generate power via the forward linear movement of the body, there is hip rotation, but also the whole body is ‘thrown’ behind the punch. Whereas a hook punch uses more rotation of the body(centrfugal) to deliver impact force.

As. a person is limited to the mass they have (actual at a given point in time and potential) the key to increasing impact force is to increase the speed of the technique they are using; hence the training for speed in boxing. Also bigger doesn’t always mean slower, when people move up in wieght classes due to increased mass, they have trained to keep up their speed.

Here a webpage that shows key boxing punches from actual fights, where you can see the diferences in techniques used to derive impact force.

https://www.coachup.com/nation/articles/fundamental-boxing-punches

charliedw
charliedw's picture

Hi Dennis Thank you for your feedback.  I'll check out the link! :)

Wastelander
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My Sensei liked to say that there were three ways to generate power for a strike--speed, bodyweight, and torque/rotation. Different techniques make use of different combinations of methods, with differing degrees of emphasis

Iain Abernethy
Iain Abernethy's picture

Hi Charlie,

That’s an interesting article and I appreciate you sharing it here. Where I depart with the article is that I don’t see “bodyweight” as being one and the same as “the weight of the body”. There’s a few times where you define bodyweight as an inherent quality of the person. For example:

“The force of the impact is partly to do with our body weight, (though we can’t do too much to change/increase it).”

“Well there’s not too much we can do about our mass.  We could eat a lot of mars bars, but that’s not very healthy …”

“Now we can all train to increase the velocity of our techniques (without the need for a single Mars bar)!

That’s not the “bodyweight” we are taking about. It’s not a given constant determined by physical size. How much bodyweight is part of the strike will depend greatly upon the quality of the technique.

Getting bodyweight into the technique is a skill (not a diet or a God given attribute).

We don’t seek to increase the bodyweight in our strikes by pigging out. We increase bodyweight in our strikes through improving our technique.

Irrespective of how much we weigh, we should maximise the mass / bodyweight in our strikes. Good technique will ensure maximum mass as well as maximum velocity.

I therefore disagree when you say:

“The force of the impact is partly to do with our body weight, (though we can’t do too much to change/increase it).”

We can do lots to change/increase the bodyweight in our techniques. Good technique will ensure maximum bodyweight behind the strike.

I do agree with your take on the technique of acceleration (very double hip), but we do need the bodyweight accelerating in the right direction. The technique of accelerating bodyweight is a vital part of power generation too.

When you show Russell’s “heavy hand” and say “Russell is not actually applying very much body weight at all”, you may be unintentionally mispresenting him. As you probably know, Russell is a proponent of “waveforms” when it comes to power generation, which he described in an article as, “a method of generating as much of your bodyweight through a given technique as possible.” Russell is therefore also of the view that bodyweight is important and technical.

When people chase maximum velocity we frequently see an arm only punch result (it’s easier to move the arm quickly than it is the entire body). We all know an arm-only punch is weak no matter how quickly it is accelerating though. That’s the danger in overemphasising “speed” and underplaying mass. The arm weighs around 5% of total bodyweight. We can’t make up for that 95% drop in the mass within an “arm only” technique with an increase in velocity. If we could, then stances would not exist :-) They exist so we can get bodyweight into strikes.

Bodyweight is technical not physical.

A fast horizontal backfist – such as we see in karate competitions – would have massive impact if velocity was the key factor, and yet we know it is a weak strike. Despite its velocity, it is weak because there is no bodyweight behind it (i.e. the M part of F=M X A is very low).

As I say, bodyweight is not a given consistent based on the weight of the body (or how many Mars Bars we eat :-).The M in the formula is determined by technique, and it will increase or decrease based on the quality and nature of the technique in question.

I can do a technique that has lots of bodyweight behind it, and then immediately do one that has little bodyweight behind it. I do it all the time when teaching to contrast right and wrong … and yet, as the bodyweight in the technique changes, the weight of my body remains the same. They are not the same thing.

Good technique will increase both mass and acceleration. A good kinetic chain will maximise both. Both are very important.

In the article you said:

“Many instructors, including some of the most reputable martial artists in the world teach that generating impact is mainly about applying your body-weight and moving it into the technique.”

I would generally agree with that. But would perhaps rephrase it as, “generating impact is mainly about accerlerating your bodyweight into the technique.”

Because you seem to have taken “bodyweight” to be one and the same as “the weight of your body”, I think you have underplayed the massive role bodyweight plays, and the skills associated with using it correctly. You may also have misunderstood the “conventional wisdom” as a result too?

As I say, bodyweight in strikes is determined in huge part by the quality of the technique. There’s no need to raid the fridge to increase the bodyweight in our strikes; we just need to strike skilfully so more of our mass is involved.

All the best,

Iain

charliedw
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Hi Iain

Thank you for your feedback. 

I was not trying to misrepresent Russell, so sorry if came across that way.  I've a huge respect for the guy (as I do you)!

I've had a think over your comments and realised that I have not expressed myself very well.

F = m * a

Here the mass (m) is a constant, which is why I've treated it as a constant throughout my article.  Mass is the amount of matter contained in a given object or person.  It is gravity that gives it weight.  So our mass is the same on Earth or in space.  But our weight is different as we obviously weigh so much down here but are weightless in space. 

I am error that I used these terms interchangeably when I shouldn't have and I appect my error and apologise.    :)

The Force of gravity is measured as acceleration (due to gravity) acting on a given mass.  So weigh is gravity acting on mass, and gravity/acceleration go hand in hand.  So weight (in the normal "how much do I weigh" sense of the word) is dependant mass and acceleration due to gravity.

So to project our body weight into a strike, we need forward acceleration acting on our mass (which is constant).  This gives the applied body weight that you talk of above.

I realise that I didn't make it clear first time round. I have re-written the article to make it clearer and more precise. 

Thank you for your help

:)

Charlie

Iain Abernethy
Iain Abernethy's picture

Hi Charlie,

Thanks for the feedback on the feedback :-) I think my main point may still have been missed though.

It’s not the technical differences between mass and weight that’s the issue. As you say, weight varies depending on gravity; whereas mass in the same the universe over. However, I don’t think that technical distinction matters when we are talking about punching people here on Earth.

For our intents and purposes, mass and weight can be thought of as being one and the same because the gravity on earth is constant and only becomes a variable to be considered when we leave the planet. You’re right there is a distinction in physics, but it does not add to our discussion on striking power.

My main point is as follows:

charliedw wrote:
Here the mass (m) is a constant, which is why I've treated it as a constant throughout my article.

While the mass of the body is constant. The mass present in the strike is NOT a constant; it will depend upon the quality of the technique.

The physics tells us that:

F = m * a

M is not the mass of the body, but the mass active in the strike. That’s the vital distinction that I feel you missed.

I have a body mass of 90KG, but if I place my hand on your chest pull, my index finger back, and then tap you with my finger (while keeping all other parts of my body totally still) it’s not the mass on my body that hits you. It’s just the mass of my finger. So, when calculating the force of a finger tap, M is not the full 90KG of my body. M would be the mass of my finger.

M is NOT constant. It can change depending on how I’m moving and what parts of my body are involved. Mass does change depending upon the quality of the technique.

As I said in the previous post:

Where I depart with the article is that I don’t see “bodyweight” as being one and the same as “the weight of the body”.

If we want to be very strict with our terminology, I can rephrase that as, “Where I depart with the article is that I don’t see “body mass” as being one and the same as “the mass of the body”. The central point remains the same.

You have treated mass/weight as a constant throughout the article; such that acceleration remains the only way in increases the force of the strikes. Mass is not a fixed constant though because the M in the formula is not the mass of the body, but the mass active in the strike. We can change it. It is not constant.

Good technique will increase the active mass (whole body behind the shot). Poor technique will reduce active mass (an uncoordinated arm-only punch). Because both mass and acceleration are variable, a good strike will have the maximum mass and maximum acceleration (balanced against tactical considerations). Both matter.

My disagreement with the article was the fact the active mass was taken as being one and the same as the mass of the body i.e. "you can’t change mass through technique (only body composition) and hence acceleration remains the only way to increase force". That’s not true because active mass – what should be used as M in the formula – can and does vary depending upon the quality of technique.

In the article and the above post, you refer to mass as being constant. That’s missing the point. The mass of our body is constant, but what matters – both from a martial perspective and that of physics – is the mass that is active in the strike. It can be increased and decreased. Mass is variable and dependent upon technique. You can’t put mass to one side as a given constant and then focuses solely on acceleration.

A finger tap is much weaker than an arm-only punch; and an arm-only strike is much weaker that a whole-body punch. The mass of the body is constant. The mass active - which is what matters - in the motion is not a given constant. It is the active mass (not body mass) that we need to apply to the formula to determine force. Mass is technical too.

In the article you have as part of the conclusion that:

charliedw wrote:
The force of the impact is partly to do with our body mass, (though we can’t do too much to change/increase it).

I disagree. The force of the impact is dependent on both the mass active in the strike and acceleration; and the quality of technique is crucial to both. We can do lots totechnically increase the mass in our strikes.

I agree with the technical points on you make on acceleration. I do, however, feel the technical aspect of mass – which is also of vital importance – has been downplayed. It is presented as a “fixed given” and not something dependent upon technique too.

I hope that helps clarify what I was driving at.

All the best,

Iain

charliedw
charliedw's picture

Hi Iain Thank you for your feedback. I agree entirely with what you say about active body mass as opposed to non active body mass.  As you say, using using the whole body mass in the technique rather than just using say the arm.   Although I hadn't put it in those terms, I thought it was implied where I talk about using the body parts in sequence.  I thought this inferred using the whole body rather than just a single body part (as there is no "sequence" in a single body part).  Sorry if I didn't make that clear, and thanks again for your feedback! :) Charlie

Iain Abernethy
Iain Abernethy's picture

Hi Charlie,

Thanks for the discussion.

charliedw wrote:
Although I hadn't put it in those terms, I thought it was implied where I talk about using the body parts in sequence.  I thought this inferred using the whole body rather than just a single body part (as there is no "sequence" in a single body part).

You did in terms of acceleration, but you also stated:

Well there’s not too much we can do about our mass, yet acceleration is something we can easily work on and improve!

There is lots we can do to increase the active mass in our strikes. The above statement (and the others quoted in my first post in this thread) inferred that mass was a given – based on bodyweight – and was not something we could change through technique.

The introduction to your piece has now been rewritten, but it originally said:

Many instructors, including some of the most reputable martial artists in the world teach that generating impact is mainly about applying your body-weight and moving it into the technique.

I read the original version of the article as a challenge to that conventional wisdom. The revised version still contains the statement:

The force of the impact is partly to do with our body mass, (though we can’t do too much to change/increase it).

There is lots we can do to change/increase mass when it comes to striking power. We make more of it active. The way that part of the conclusion is written seems contrary to the ideas that it is active mass that applies to the formula, and that active mass can be drastically increased with good technique.

charliedw wrote:
I thought this inferred using the whole body rather than just a single body part (as there is no "sequence" in a single body part).

As previously stated, your points on the mechanics of acceleration are ones I totally agree with. It’s common for people to miss that and move body parts together and not as an accelerating chain. The result is a technique that is slower and weaker. Totally with you there and I think you’ve expressed such an important concept very clearly. It’s is possible to accelerate a strike – using the entire body – in that way that does not get any meaningful bodyweight into the technique though. For example, I can pivot the hip – in whole or in part – away from the target. It is still rotating and will accelerate the arm just the same, but the active mass will drop drastically because a large part of that mass is moving in the wrong direction. I therefore don’t feel we can explain the mechanics of acceleration and expect active bodyweight to take care of itself. Bodyweight has its own technical considerations.

The optimum technique will accelerate as much mass as possible in the direction of the strike. It is possible to have a technique that has mass and little acceleration. It is also possible to have a technique that has acceleration but little mass. While everything always needs balanced against tactical considerations, when it comes to isolated power generation, we always need as much mass as possible accelerating as quickly as possible.

As I read the article (particularly in its original form) it seemed to be downplaying the role of mass and the part good technique plays in that. Having discussed it, I don’t think we are that far apart.

Thanks for the discussion!

All the best,

Iain