Time on Target
"The creation of an appropriate pause in the cycle of extension/retraction allows the transference of power and intent."
I would like to discuss this point, because it is an interesting one. First of all this discussion would only be applicable to more senior ranks.
The point above (sticking the strike at the point of contact) can be demonstrated to show that it has more power than a quickly retracted strike. I think some refer to it as "time on target". There seems to be no doubt that the demonstrations show that hitting and sticking for a moment clearly hits harder than the strike that is retracted quickly.
The discussion I would like to have is that physics says that the shorter the time on target the MORE force that will be delivered. The longer the time on target the LESS force that will be transferred.
The force equation is detailed as mass x (the speed of the strike at the point of impact / the time it takes to dissipate the force into the target). F = m x (ad/at) (Sorry can't superscript the d and t.) Therefore the longer it takes to dissipate the force (increase the value of "at") actually reduces the force delivered.
So based on physics, using "time on target" should have less impact than the quickly retracted strike.
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Then why can it be clearly demonstrated to have the opposite effect?
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I believe this is because the physics only works at the point where the strike is "complete", or where the energy is completely transferred to the opponent.
Most people when attempting to withdraw their strikes quickly begin to do so before the end (completion) of the strike and the transfer of force. Therefore, retain the force themselves, in other words they actually decrease the value of "ad". Using the formula, decreasing "ad" clearly decreases the force of the strike.
This is the effect that most people have when they try to retract a strike quickly. They retract the strike too quickly, too soon.
Based on physics, if you are dissipating the force, then the time on target should be lessened - no pause. This will actually increase the force of the strike. But it will only do so if the mass/speed/force has been fully transferred.
So how can we achieve this? How can we learn when the strike is "complete"?
This is something that I have been working on. If you strike, without retraction (a pause at the end of your strike), closely observe the action of your arm.
The point the arm "pauses" should be a few inches shorter in distance than the strike went. This is because the strike should be perfectly relaxed. The strike goes out to the natural limit of the limb's extension and then the natural elasticity of the limb begins to retract it. The pause is actually after the delivery (completion) of the strike. It is NOT at the full extension (end) of the strike.
It is at this point, the point of the natural limit of the limbs extension, that the force is transferred into the opponent. It is at this point, the speed/mass/force of the strike has been delivered. That is the point where any further contact will actually decrease the force of the strike.
When the limb begins to naturally contract, or withdraw, you can add to that action for full retraction without any loss in force, because the force has already been transferred.
Of course, this is one of those easier said than done things.
Please note that by adding to the natural retraction of the strike you increase the speed of the retraction. Getting your arm back into position is important.
I try to work on feeling this in Sanchin. I do "pause" but only after the natural retraction has begun. I try to feel that natural extension and the point of natural retraction so that I can complete a strike and retract it without a perceptual pause.
The reason I said this discussion is more for senior ranks is that new students will often retract too quickly (too soon). The feeling required to know when the strike is naturally retracting is an advanced one.
It is easier for the new student to learn to stick the strike (use time on target). In this way they are at least not pulling mass and speed out of the strike before the moment of contact.
As a teacher, I would rather have new students use "time on target" rather than having them pull power out of a strike. It results in a more powerful strike than pulling the power out by retracting too quickly. Another balancing act again.
Comments?
Rick
Time on Target works, but what about physics?
Moderator: Available
Time on Target works, but what about physics?
Rick,
The way I practice in kata is to act like a whip. I let the arm or leg reach it's full extension and snap itself back. No matter where the surface of the target may be, I prefer to see the focus point as being the full extension of the limb. If the skin is closer than the full extension, there will be no "crack", but there will be penetration. This could even end up as a pushing action if close enough, and linked to the movement of body mass. As long as I don't put any artificial breaks in the application of continuous motion, I'm happy. I just want to be as relaxed as I can, and keep moving.
I'm not an advanced rank, but that's what I'm working with.
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sean
The way I practice in kata is to act like a whip. I let the arm or leg reach it's full extension and snap itself back. No matter where the surface of the target may be, I prefer to see the focus point as being the full extension of the limb. If the skin is closer than the full extension, there will be no "crack", but there will be penetration. This could even end up as a pushing action if close enough, and linked to the movement of body mass. As long as I don't put any artificial breaks in the application of continuous motion, I'm happy. I just want to be as relaxed as I can, and keep moving.
I'm not an advanced rank, but that's what I'm working with.
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sean
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Rick Wilson
Time on Target works, but what about physics?
Hi Sean:
Yes, the whip method of striking definitely makes use of the principle that I'm referring to (or at least as I understand it, mostly through Erle Montigue tapes). It also makes strong use of the physics referred to.
The whip is an effective method of striking, but different from the approach that I take. (See my thread "The Intricacies of Body Mechanics and Body Alignment in Striking" October 3, 2000.) I find that I cannot intergrate the body mechanics and alignment that I want when working with the whip. Different approaches for different folks.
Different approaches but they share some principles.
Thanks for the comments,
Rick
P.S. I don't consider myself to be "Senior" so thanks for jumping in. Although following the new ranking system showing up on another forum I suppose I could be a Junior Maestro
?
Yes, the whip method of striking definitely makes use of the principle that I'm referring to (or at least as I understand it, mostly through Erle Montigue tapes). It also makes strong use of the physics referred to.
The whip is an effective method of striking, but different from the approach that I take. (See my thread "The Intricacies of Body Mechanics and Body Alignment in Striking" October 3, 2000.) I find that I cannot intergrate the body mechanics and alignment that I want when working with the whip. Different approaches for different folks.
Different approaches but they share some principles.
Thanks for the comments,
Rick
P.S. I don't consider myself to be "Senior" so thanks for jumping in. Although following the new ranking system showing up on another forum I suppose I could be a Junior Maestro
?-
Rick Wilson
Time on Target works, but what about physics?
So as to avoid any misunderstandings or misrepresentations, any physics stuff I ever post is usually generated by an engineer friend of mine, Rick Bottomley.
Rick
Rick
Time on Target works, but what about physics?
Rick,
Another good post.
This can be a vexing problem. I always remember GEM-sensei teaching me to hit “bone” while managing to keep the opponent at hitting “skin”!
I teach my students to envision contact with the “rear” of the target before retreating the strike. I.E., if you target the chin, snap the punch through the chin aiming the blow to the back of the head.
If you kick someone’s leg with a shin kick, envision the target as the other leg to be reached through the first leg you contact.
If you punch someone in the stomach or chest, aim the shot at the spine.
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Van Canna
Another good post.
This can be a vexing problem. I always remember GEM-sensei teaching me to hit “bone” while managing to keep the opponent at hitting “skin”!
I teach my students to envision contact with the “rear” of the target before retreating the strike. I.E., if you target the chin, snap the punch through the chin aiming the blow to the back of the head.
If you kick someone’s leg with a shin kick, envision the target as the other leg to be reached through the first leg you contact.
If you punch someone in the stomach or chest, aim the shot at the spine.
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Van Canna
Time on Target works, but what about physics?
Wing Chun boxers like the close range, and attempt to strike with very deep penetration.
This is as Mr. Van Canna’s sensei suggested, “If you punch someone in the stomach or chest, aim the shot at the spine.”
As I understand the concept of “time on target” from Mr. Rick Wilson’s post, this would also lengthen the time on target by the nature of the deep punch staying in contact with the target longer.
Although using a different technique, to obtain the same goal of energy transfer.
No matter which way, using the pause, or the deep punch, you've got to have some hard hands for these punches.
This is as Mr. Van Canna’s sensei suggested, “If you punch someone in the stomach or chest, aim the shot at the spine.”
As I understand the concept of “time on target” from Mr. Rick Wilson’s post, this would also lengthen the time on target by the nature of the deep punch staying in contact with the target longer.
Although using a different technique, to obtain the same goal of energy transfer.
No matter which way, using the pause, or the deep punch, you've got to have some hard hands for these punches.
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Allen M.
Time on Target works, but what about physics?
8 Ball. Side pocket!
Spheres and Sph-ysics. dynamics and statics. Angles, timing, impact, a good eye, and a straight shot.
Fighting and the proper application of power is so complex.
Spheres and Sph-ysics. dynamics and statics. Angles, timing, impact, a good eye, and a straight shot.
Fighting and the proper application of power is so complex.
Time on Target works, but what about physics?
If I follow, the assumption to be tested is: lengthening the time the force is dissippated over will diminish the force delivered.
This is because if your fist is to be decelerated from full speed to stopped, and F=ma. That is, your arm (mass) will experience a force exerted by the body of the target that decelerates it, and this (negative) acceleration will be proportional to the force of the body on the fist, or, conversely the fist on the body.
I'm no physics master but I did tutor MCAT physics for a few years, and there are a couple things I think are worth considering.
First, this doesn't apply to us except by sort of analogy. These laws deal with ideal situations and bodies don't qualify. Newtonian physics says that no solitary mass with an angular momentum can change it while falling; a soccer ball spinning will stay so, or one not will stay not. But a cat is not a rigid object and can create and then halt spinning midair to land on its feet. So we shouldn't expect these laws to give us precise answers.
Second, there is NO connection between time on contact and rate of deceleration. One could hit, decelerating over time X, and then remain on contact for times Y or Z; the concern about deceleration governing force applied tells us nothing (X in both cases) about why times on contact X+Y and X+Z may have different effects.
Third, as has been mentioned, the student who has no time on contact is generally not hitting with penetrating power. They stop at the surface of the target. Press into a stomach and you'll see the resistive force increases with depth; the stomach can't be stopping the punch at the surface. No force from stomach to fist is no force from fist to stomach. It is the student who has decelerated the punch, not the target, so the student doesn't expend the punch's energy on the foe, but rather on his/her own muscles. So it doesn't hurt as much.
Energy is another way to approach this subject. Often in problems there's a long and complicated solution involving acceleration and distance equations, and a very simple one involving energy. In this case the energy of the punch is 1/2mass x velocity (squared). Worth noting is that velocity is the dominant variable since it is squared; the student who decelerates the punch just before impact removes most of the kinetic energy before it is transfered. Also decelerating "in" the target will have the same effect. Stomachs have some padding and give and the first inch of penetration usually isn't a big deal; if the student decelerates over this distance, no energy is left to transfer to the organs, which is where the hurt comes in.
The goal is simply to expend the KE on the target and not one's own muscles.
Another goal is to cause penetration--which, instead of jarring the surface, will go towards displacing the inner targets. The head, not just whacked, will be sent flying, or the organs of the stomach will be displaced or compressed. One can see this is important because if you walk up to someone with a relaxed stomach and press deeply into their gut, you can cause much more pain even with a slower motion than with a very fast one when the stomach is tensed. I don't know of any physics that gets at this clearly.
There are a couple other concepts that could help, like momentum, or impulse, but since we defy standard physics because of the way we're built, I think we're better off just knowing how to hit and doing it. Whether we use physics or chi or time on contact to explain the effect we've all felt should depend on which works best for the speaker and the audience.
This is because if your fist is to be decelerated from full speed to stopped, and F=ma. That is, your arm (mass) will experience a force exerted by the body of the target that decelerates it, and this (negative) acceleration will be proportional to the force of the body on the fist, or, conversely the fist on the body.
I'm no physics master but I did tutor MCAT physics for a few years, and there are a couple things I think are worth considering.
First, this doesn't apply to us except by sort of analogy. These laws deal with ideal situations and bodies don't qualify. Newtonian physics says that no solitary mass with an angular momentum can change it while falling; a soccer ball spinning will stay so, or one not will stay not. But a cat is not a rigid object and can create and then halt spinning midair to land on its feet. So we shouldn't expect these laws to give us precise answers.
Second, there is NO connection between time on contact and rate of deceleration. One could hit, decelerating over time X, and then remain on contact for times Y or Z; the concern about deceleration governing force applied tells us nothing (X in both cases) about why times on contact X+Y and X+Z may have different effects.
Third, as has been mentioned, the student who has no time on contact is generally not hitting with penetrating power. They stop at the surface of the target. Press into a stomach and you'll see the resistive force increases with depth; the stomach can't be stopping the punch at the surface. No force from stomach to fist is no force from fist to stomach. It is the student who has decelerated the punch, not the target, so the student doesn't expend the punch's energy on the foe, but rather on his/her own muscles. So it doesn't hurt as much.
Energy is another way to approach this subject. Often in problems there's a long and complicated solution involving acceleration and distance equations, and a very simple one involving energy. In this case the energy of the punch is 1/2mass x velocity (squared). Worth noting is that velocity is the dominant variable since it is squared; the student who decelerates the punch just before impact removes most of the kinetic energy before it is transfered. Also decelerating "in" the target will have the same effect. Stomachs have some padding and give and the first inch of penetration usually isn't a big deal; if the student decelerates over this distance, no energy is left to transfer to the organs, which is where the hurt comes in.
The goal is simply to expend the KE on the target and not one's own muscles.
Another goal is to cause penetration--which, instead of jarring the surface, will go towards displacing the inner targets. The head, not just whacked, will be sent flying, or the organs of the stomach will be displaced or compressed. One can see this is important because if you walk up to someone with a relaxed stomach and press deeply into their gut, you can cause much more pain even with a slower motion than with a very fast one when the stomach is tensed. I don't know of any physics that gets at this clearly.
There are a couple other concepts that could help, like momentum, or impulse, but since we defy standard physics because of the way we're built, I think we're better off just knowing how to hit and doing it. Whether we use physics or chi or time on contact to explain the effect we've all felt should depend on which works best for the speaker and the audience.
Time on Target works, but what about physics?
While Canna-sempai mentions the correct visualization, which I agree with and use... and others have made great and enlightening contributions...
I don't see these really addressing the specific physics query that Wilson-san posed.
I'd like to give it a try...
First, let's clear up the equation and then we can dissect the meaning and results.
The equation is: F = ma :: Force = mass X acceleration.
Where F is the Force generated, mass is the amount of stuff (it is not the same as weight, but rather also includes such things as density), and acceleration is the change in the rate of velocity over time ( dv/dt ).
The last variable seems to be a little bit of a problem. "Velocity" isn't just speed... it's speed and direction and is the change in distance (usually in meters) over time ( dm/dt ). You can have a positive velocity and concurrently have positive, neutral or negative acceleration.
Here's an example: Canna-sempai is sitting at a red light in his Ferrari (had to be a fine Italian automobile ). Light changes to green and he gives it the gas... velocity is increasing and so does acceleration. Now he reaches his target speed (velocity, in this case) of 120 mph... at that point acceleration is neutral. In other words he is no longer "accelerating", yet he still has a positive "velocity" (speed). Then he sees someone with flashing lights in his rearview mirror and decides to slow down to 65 mph... While he still has a positive velocity, the act of slowing down has created a negative acceleration. (deceleration)
It is important to also realize that this applies only to the actual act of throwing a punch or kick! In other words, there are two uses of the equation of F = ma that must be calculated when striking an opponent! The first one is mainly about the attacker and the second is mainly about the defender. The original query concerning the transferred or "felt" Force requires a combination of the two equations.
The attacker's (first) equation:
This is the Force that the attacker is generating by accelerating (say, throwing a punch at an ever increasing speed) a mass (say the attacker's fist). Also the mass of your fist doesn't vary much and if you make your fist tight, it remains constant... Therefore, most of the Force must (by definition) come from the acceleration (throwing the punch). That's where the whole concept of throwing a faster punch comes into play. It's not really that it's a "faster" punch, but rather that it has a large positive acceleration. Muscles move faster when they are relaxed and the mass of your fist is at it's greatest the tighter you make your fist, which requires tense muscles. In order to optimize both aspects, the advanced kara-te-ka must learn to throw a punch with relaxed muscles (increase the acceleration) and tense the fist (increase the mass) at the last possible instant right at impact.
The defender's (second) equation:
Still the same F = ma, only the meaning of the variables have changed. Now we're discussing the mass and acceleration (movement) of the target. Here again, mass is basically a constant. However, the acceleration of the opponent is important to the final outcome.
For example: If Canna-sempai is driving his Ferrari and I'm in my AMX and we are side-by-side on I-495 doing exactly the same speed there is no difference in acceleration. But if I'm driving at 65 and he is going much faster than I am and strikes me from the rear, the aggregate acceleration in our Force equation is his acceleration minus my acceleration. Naturally, the opposite occurs when we collide head-on...
So, if the defender has an acceleration that is nearly identical to the acceleration of your punch (in other words, he "swallows" the punch by moving backwards), the resultant Force is greatly diminished. BUT, if the defender happens to be stepping in at the same time that you throw your punch... Ker-pow!
Therefore, we can find out what the "felt" or transferred Force is only by looking at both aspects. And there is also the fact that actual contact must be made! (I can stand in my office here and throw fantastic punches at Canna-sempai all day long and since we are miles apart, there will never be any transferred force... agreed? I hope... )
To apply this to Wilson-san's original dilemma (that "time on target" should have less impact, but actually doesn't), the fact is that, it's the hypothesis that needs correcting, not the physics. "Time on target" , as generally discussed by senior martial artists, does not mean throwing the strike and stopping or retracting at the point of impact (which is the way the equations would have to be combined in order to get the aforementioned results). Both stopping or retracting right at the point of impact will decrease the amount of transferred force/energy from optimum. The concept of "time on target" is the same as "striking through" the target. The acceleration of the strike should continue to increase beyond the point of impact... as Canna-sempai and Maestro GEM (hehehe ) teach.
Then there are also the necessary components of Kinetic Energy to think about, which is a different equation and different application...
[This message has been edited by Panther (edited October 16, 2000).]
I don't see these really addressing the specific physics query that Wilson-san posed.
I'd like to give it a try...
First, let's clear up the equation and then we can dissect the meaning and results.
The equation is: F = ma :: Force = mass X acceleration.
Where F is the Force generated, mass is the amount of stuff (it is not the same as weight, but rather also includes such things as density), and acceleration is the change in the rate of velocity over time ( dv/dt ).
The last variable seems to be a little bit of a problem. "Velocity" isn't just speed... it's speed and direction and is the change in distance (usually in meters) over time ( dm/dt ). You can have a positive velocity and concurrently have positive, neutral or negative acceleration.
Here's an example: Canna-sempai is sitting at a red light in his Ferrari (had to be a fine Italian automobile
). Light changes to green and he gives it the gas... velocity is increasing and so does acceleration. Now he reaches his target speed (velocity, in this case) of 120 mph... at that point acceleration is neutral. In other words he is no longer "accelerating", yet he still has a positive "velocity" (speed). Then he sees someone with flashing lights in his rearview mirror and decides to slow down to 65 mph... While he still has a positive velocity, the act of slowing down has created a negative acceleration. (deceleration)It is important to also realize that this applies only to the actual act of throwing a punch or kick! In other words, there are two uses of the equation of F = ma that must be calculated when striking an opponent! The first one is mainly about the attacker and the second is mainly about the defender. The original query concerning the transferred or "felt" Force requires a combination of the two equations.
The attacker's (first) equation:
This is the Force that the attacker is generating by accelerating (say, throwing a punch at an ever increasing speed) a mass (say the attacker's fist). Also the mass of your fist doesn't vary much and if you make your fist tight, it remains constant... Therefore, most of the Force must (by definition) come from the acceleration (throwing the punch). That's where the whole concept of throwing a faster punch comes into play. It's not really that it's a "faster" punch, but rather that it has a large positive acceleration. Muscles move faster when they are relaxed and the mass of your fist is at it's greatest the tighter you make your fist, which requires tense muscles. In order to optimize both aspects, the advanced kara-te-ka must learn to throw a punch with relaxed muscles (increase the acceleration) and tense the fist (increase the mass) at the last possible instant right at impact.
The defender's (second) equation:
Still the same F = ma, only the meaning of the variables have changed. Now we're discussing the mass and acceleration (movement) of the target. Here again, mass is basically a constant. However, the acceleration of the opponent is important to the final outcome.
For example: If Canna-sempai is driving his Ferrari and I'm in my AMX and we are side-by-side on I-495 doing exactly the same speed there is no difference in acceleration. But if I'm driving at 65 and he is going much faster than I am and strikes me from the rear, the aggregate acceleration in our Force equation is his acceleration minus my acceleration. Naturally, the opposite occurs when we collide head-on...
So, if the defender has an acceleration that is nearly identical to the acceleration of your punch (in other words, he "swallows" the punch by moving backwards), the resultant Force is greatly diminished. BUT, if the defender happens to be stepping in at the same time that you throw your punch... Ker-pow!
Therefore, we can find out what the "felt" or transferred Force is only by looking at both aspects. And there is also the fact that actual contact must be made! (I can stand in my office here and throw fantastic punches at Canna-sempai all day long and since we are miles apart, there will never be any transferred force... agreed? I hope... )
To apply this to Wilson-san's original dilemma (that "time on target" should have less impact, but actually doesn't), the fact is that, it's the hypothesis that needs correcting, not the physics.
"Time on target" , as generally discussed by senior martial artists, does not mean throwing the strike and stopping or retracting at the point of impact (which is the way the equations would have to be combined in order to get the aforementioned results). Both stopping or retracting right at the point of impact will decrease the amount of transferred force/energy from optimum. The concept of "time on target" is the same as "striking through" the target. The acceleration of the strike should continue to increase beyond the point of impact... as Canna-sempai and Maestro GEM (hehehe ) teach.Then there are also the necessary components of Kinetic Energy to think about, which is a different equation and different application...
[This message has been edited by Panther (edited October 16, 2000).]
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Allen M.
Time on Target works, but what about physics?
I call time-on-target "sink your power in." In other words, I like my fist or foot to be imbedded well inside someone by the time it reaches full extension. That way, most of the power transmits to the receiver, rather than disapating, just like shoving a high voltage wire tightly against ground, or putting a screwdriver across car battery terminals.
Tony, Time on target with your kick in sparring is gonna get your leg caught. But in fighting, it's the same as kicking your attacker through the wall. More often it is done, however, with the good ole' fashioned side thrust kick against a heavy bag.
In the equations above, F peters out to '0' again at full extention, so you'd better "be there" by then, unless you include the venomous fluid shooting out the end of your strike. Maybe your venom is the second derivative of the above equation (heh, heh).
Actually, though, using Van's method, F does not go to zero at full extension, as the second wave of power travels right behind the first.
Tony, Time on target with your kick in sparring is gonna get your leg caught. But in fighting, it's the same as kicking your attacker through the wall. More often it is done, however, with the good ole' fashioned side thrust kick against a heavy bag.
In the equations above, F peters out to '0' again at full extention, so you'd better "be there" by then, unless you include the venomous fluid shooting out the end of your strike. Maybe your venom is the second derivative of the above equation (heh, heh).
Actually, though, using Van's method, F does not go to zero at full extension, as the second wave of power travels right behind the first.
Time on Target works, but what about physics?
Another definition of time on target could be if you throw that side kick and then continue with the momentum until you're standing on a knee or whatever.
Is there a striking range and a grappling range, or is there just the range where you can strike and grapple at the same time. The other might be called "out of" range.
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sean
Is there a striking range and a grappling range, or is there just the range where you can strike and grapple at the same time. The other might be called "out of" range.
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sean
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Rick Wilson
Time on Target works, but what about physics?
Thank you to everyone for getting this rolling.
Panther:
Thoughtful post, thanks.
Going to try and get my friend Rick Bottomley to reply to most of your post -- getting beyond me.
However, I am going to disagree with your comment:
"Also the mass of your fist doesn't vary much and if you make your fist tight, it remains constant... Therefore, most of the Force must (by definition) come from the acceleration (throwing the punch)."
This is the very problem with most martial artists, they only hit with their arm and fist. Striking with the whole body incorporates the entire mass of the body.
The amount of available mass that someone can place into a strike varies greatly with proper technique.
Furthermore, when discussing striking Mass should be refined as Connected Mass. A strike with mass connected to the ground is far more powerful than one with less mass or mass that is not connected.
Great stuff, I hope Rick B. jumps in.
Rick
Panther:
Thoughtful post, thanks.
Going to try and get my friend Rick Bottomley to reply to most of your post -- getting beyond me.
However, I am going to disagree with your comment:
"Also the mass of your fist doesn't vary much and if you make your fist tight, it remains constant... Therefore, most of the Force must (by definition) come from the acceleration (throwing the punch)."
This is the very problem with most martial artists, they only hit with their arm and fist. Striking with the whole body incorporates the entire mass of the body.
The amount of available mass that someone can place into a strike varies greatly with proper technique.
Furthermore, when discussing striking Mass should be refined as Connected Mass. A strike with mass connected to the ground is far more powerful than one with less mass or mass that is not connected.
Great stuff, I hope Rick B. jumps in.
Rick
Time on Target works, but what about physics?
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Rick Wilson:
However, I am going to disagree with your comment:
"Also the mass of your fist doesn't vary much and if you make your fist tight, it remains constant... Therefore, most of the Force must (by definition) come from the acceleration (throwing the punch)."
This is the very problem with most martial artists, they only hit with their arm and fist. Striking with the whole body incorporates the entire mass of the body.
The amount of available mass that someone can place into a strike varies greatly with proper technique.
Furthermore, when discussing striking Mass should be refined as Connected Mass. A strike with mass connected to the ground is far more powerful than one with less mass or mass that is not connected.<HR></BLOCKQUOTE>
No disagreement from me! You're quite correct. I was trying to make things as simple as possible in the example/discussion, so I limited the variables. (Kind of like the old "frictionless plane" or "massless object" that are used in beginning physics texts... ) I originally went down the path of discussing centripetal (as well as centrifugal) force addition from the body/hip rotation... the effects of proper arm, shoulder, back, hip, leg alignment... the increased acceleration and addition of mass-momentum from stepping while punching... etc... but it not only got long winded and muddy (complicated), I was afraid it would come across as too "scientific-snooty" (which created a misunderstanding in another recent thread, so I really wanted to avoid it again ).
What the proper alignment/technique/grounding does is 1) allow for better acceleration without deviation, 2) prevent the resulting force that is generated from being (mis)directed tangentially, 3) allow the mass of the entire body to contribute to the force generated, and 4) gain strength/momentum from "pushing off" (from the ground or a wall or whatever... generally it's thought of as "grounding", but it doesn't necessarily have to be the ground).
But I kind of like the idea of the "oozing venom of DOOM"(tm)... makes all this physics stuff (which you certainly aren't going to be thinking about when the brown stuff strikes the rotating blades of the oscillating device) a moot point!
[This message has been edited by Panther (edited October 17, 2000).]
However, I am going to disagree with your comment:
"Also the mass of your fist doesn't vary much and if you make your fist tight, it remains constant... Therefore, most of the Force must (by definition) come from the acceleration (throwing the punch)."
This is the very problem with most martial artists, they only hit with their arm and fist. Striking with the whole body incorporates the entire mass of the body.
The amount of available mass that someone can place into a strike varies greatly with proper technique.
Furthermore, when discussing striking Mass should be refined as Connected Mass. A strike with mass connected to the ground is far more powerful than one with less mass or mass that is not connected.<HR></BLOCKQUOTE>
No disagreement from me! You're quite correct. I was trying to make things as simple as possible in the example/discussion, so I limited the variables. (Kind of like the old "frictionless plane" or "massless object" that are used in beginning physics texts...
) I originally went down the path of discussing centripetal (as well as centrifugal) force addition from the body/hip rotation... the effects of proper arm, shoulder, back, hip, leg alignment... the increased acceleration and addition of mass-momentum from stepping while punching... etc... but it not only got long winded and muddy (complicated), I was afraid it would come across as too "scientific-snooty" (which created a misunderstanding in another recent thread, so I really wanted to avoid it again ).What the proper alignment/technique/grounding does is 1) allow for better acceleration without deviation, 2) prevent the resulting force that is generated from being (mis)directed tangentially, 3) allow the mass of the entire body to contribute to the force generated, and 4) gain strength/momentum from "pushing off" (from the ground or a wall or whatever... generally it's thought of as "grounding", but it doesn't necessarily have to be the ground).
But I kind of like the idea of the "oozing venom of DOOM"(tm)... makes all this physics stuff (which you certainly aren't going to be thinking about when the brown stuff strikes the rotating blades of the oscillating device) a moot point!
[This message has been edited by Panther (edited October 17, 2000).]
Time on Target works, but what about physics?
Glasheen-sempai, excellent clarification... Thanks...
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Bill Glasheen:
I differ with him on the tightness of the fist issue vs. mass, etc. But he's on the right track.
(snip)
It also may crumple. This would be like having a soft fist. If we make the fist hard when we contact, this is like having a very rigid-body vehicle that doesn't crumple at all. <HR></BLOCKQUOTE>
Glasheen-sempai, I know that you know (that I know that... ummm, sorry)... mass and weight aren't the same thing. I know what you're getting at is that realistically speaking the mass of an object doesn't change. Mass is the amount of stuff and is based on both the volume and the density of "stuff". Since the looser fist has a greater volume with less density while the tighter fist has a greater density in a lower volume, they cancel out and the mass is the same. I kind of "flubbed" that little point in trying to get to the density idea, which you explained much better as the car's "rigidity". Basically, I was trying to say that if I have a 1 oz lead ball and a 1 oz stryofoam ball, they are both the same weight, but lead is denser "stuff" in a smaller volume, so that 1 oz of lead hitting is going to hurt more... In reality, it's the rigidity that you mention... the styrofoam is going to yield, but the lead won't!
(See, I do know the definition of "mass"... )
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Bill Glasheen:
I differ with him on the tightness of the fist issue vs. mass, etc. But he's on the right track.
(snip)
It also may crumple. This would be like having a soft fist. If we make the fist hard when we contact, this is like having a very rigid-body vehicle that doesn't crumple at all. <HR></BLOCKQUOTE>
Glasheen-sempai, I know that you know (that I know that... ummm, sorry)... mass and weight aren't the same thing. I know what you're getting at is that realistically speaking the mass of an object doesn't change. Mass is the amount of stuff and is based on both the volume and the density of "stuff". Since the looser fist has a greater volume with less density while the tighter fist has a greater density in a lower volume, they cancel out and the mass is the same. I kind of "flubbed" that little point in trying to get to the density idea, which you explained much better as the car's "rigidity". Basically, I was trying to say that if I have a 1 oz lead ball and a 1 oz stryofoam ball, they are both the same weight, but lead is denser "stuff" in a smaller volume, so that 1 oz of lead hitting is going to hurt more... In reality, it's the rigidity that you mention... the styrofoam is going to yield, but the lead won't!
(See, I do know the definition of "mass"...
)-
Bill Glasheen
- Posts: 17299
- Joined: Thu Mar 11, 1999 6:01 am
- Location: Richmond, VA --- Louisville, KY
Time on Target works, but what about physics?
Panther
Actually Ian's comment about the oversimplification and your analogy of the automobile were both right on target. You just had a few details that needed to be straightened out.
You spoke like an engineer, Panther. Very often engineers use analogues to describe a situation. I could very well have used an electrical circuit to model the whole thing. Engineers do this because the mathematics and principles are often the same across many venues (mechanics, electricity, hydraulics, etc). Once you show it can be approximated by a circuit or a mechanical model, then you can easily jump into the mathematics that describe that simpler situation.
The human body is very complex. I only briefly touched on the nonlinear properties of human tissue, and the complex set of nerve impulses and subsequent muscular contractions that make up the situation. In the end though, the simpler analogues are "close enough" to get the principles across and make some gross calculations.
I didn't go much into the "mass" issue in the kinetic energy component. The definition of the mass depends somewhat on how you throw your punch, and whether or not you move forward (or rotationally) when you punch in any way. It is complex. Others touched on that a bit.
- Bill
Actually Ian's comment about the oversimplification and your analogy of the automobile were both right on target. You just had a few details that needed to be straightened out.
You spoke like an engineer, Panther. Very often engineers use analogues to describe a situation. I could very well have used an electrical circuit to model the whole thing. Engineers do this because the mathematics and principles are often the same across many venues (mechanics, electricity, hydraulics, etc). Once you show it can be approximated by a circuit or a mechanical model, then you can easily jump into the mathematics that describe that simpler situation.
The human body is very complex. I only briefly touched on the nonlinear properties of human tissue, and the complex set of nerve impulses and subsequent muscular contractions that make up the situation. In the end though, the simpler analogues are "close enough" to get the principles across and make some gross calculations.
I didn't go much into the "mass" issue in the kinetic energy component. The definition of the mass depends somewhat on how you throw your punch, and whether or not you move forward (or rotationally) when you punch in any way. It is complex. Others touched on that a bit.
- Bill
