Illustration of kinetic chain

[mandrin]

Noticing the severe editing, I am quite glad that I saved continuously the whole thread so I have all the ineptitudes produced by nmgofler for possible future use. You never know. Better be prepared.

At least it seemed to have been of interest to quite a few people but perhaps for the same reason pro hockey interests some people, i.e., the insane violence and the occasional drirty fighting.

I mentioned before in this thread that Prof Jorgensen, and also Dr Cochran and his impressive research group, were wrong with regard to estimating the power in a full blown golfer's down swing.

I will come back on this eventually in a future thread. But I am not going to throw this onto the forum as a quick, back on an envelope, developed idea. It will be done in serious and responsible manner.

It is indeed a very interesting topic as it elucidates the mechanism and hence the exact manner in which energy/power flows from proximal to distal elements in a kinetic chain.


Btw., Deadly_Scope, you can stop chewing your popcorn. Regrettable perhaps, but the show is finished.

 

[Bronco Billy]

Mandrin... This is of Great Interest to Me....

Noticing the severe editing, I am quite glad that I saved continuously the whole thread so I have all the ineptitudes produced by nmgofler for possible future use. You never know. Better be prepared.

At least it seemed to have been of interest to quite a few people but perhaps for the same reason pro hockey interests some people, i.e., the insane violence and the occasional drirty fighting.

I mentioned before in this thread that Prof Jorgensen, and also Dr Cochran and his impressive research group, were wrong with regard to estimating the power in a full blown golfer's down swing.

I will come back on this eventually in a future thread. But I am not going to throw this onto the forum as a quick, back on an envelope, developed idea. It will be done in serious and responsible manner.

It is indeed a very interesting topic as it elucidates the mechanism and hence the exact manner in which energy/power flows from proximal to distal elements in a kinetic chain.


Btw., Deadly_Scope, you can stop chewing your popcorn. Regrettable perhaps, but the show is finished.

I for One Find these Exchanges of Ideas Between Diverse Opinions VERY EDUCATIONAL as Well as Entertaining..... I Sure Hope this Forum will Return to the Free Exchanges of Information as it was in the Past.... In Any Event I Truly Hope You and Nm have the Greatest of Days........

 

[jaridyard]

With reference to the original post (hard to remember it after all the 'handbags' seen throughout this thread), it's long been recognised that all sporting motions have a sequence, usually proximal to distal in elite performers.
The snapping however I have an issue with, it's known that when a distal segment accelerates the proximal segment slows, why however is unclear. Putnam suggests that deceleration happens after peak velocity of a segment has been achieved and the transfer of that peak energy has occurred. Marshall & Wood showed a reversal of joint torques late in the movement that served to increase distal velocity.
So we can agree proximal slows as distal accelerates. The 'why' needs an answer before we talk of snapping/deliberately slowing segments. The possible reasons I can think of are:
1) Full range of motion of proximal segment is reached or approached and slowing is inevitable. Stretch-Shortening cycle.
2) The characteristics of the system change, for example, a golfer releases the club early increasing the distance from the centre of rotation to the clubhead slowing the velocity of the centre. Think ice skater spinning.
3) An innate ability of elite performers to co-ordinate the transfer of momentum by firing/un-firing muscle groups in perfect sequence.

I bet there are many more reasons possible, one thing I'm sure of however is that in Mandrins model whether correct or not, the proximal segments acting solely under gravitational pull cannot be actively exerting any reverse torque on the joints!

 

[Tom Bartlett]

A note from the moderator

A debate is fine when it is done correctly. This tripe will not be tolerated. I'm not going to allow a few people to ruin it for the rest.

 

[shoot54today]

Tiger's Transition :: Oceanic Time Warner Cable's AroundHawaii.com



Check this out.
Hitting is a Guess (video # 2 of Babe Ruth on the right)

 

[Bronco Billy]

Very Informative Post... Sometimes Causes and Effects Become Reversed....

With reference to the original post (hard to remember it after all the 'handbags' seen throughout this thread), it's long been recognised that all sporting motions have a sequence, usually proximal to distal in elite performers.
The snapping however I have an issue with, it's known that when a distal segment accelerates the proximal segment slows, why however is unclear. Putnam suggests that deceleration happens after peak velocity of a segment has been achieved and the transfer of that peak energy has occurred. Marshall & Wood showed a reversal of joint torques late in the movement that served to increase distal velocity.
So we can agree proximal slows as distal accelerates. The 'why' needs an answer before we talk of snapping/deliberately slowing segments. The possible reasons I can think of are:
1) Full range of motion of proximal segment is reached or approached and slowing is inevitable. Stretch-Shortening cycle.
2) The characteristics of the system change, for example, a golfer releases the club early increasing the distance from the centre of rotation to the clubhead slowing the velocity of the centre. Think ice skater spinning.
3) An innate ability of elite performers to co-ordinate the transfer of momentum by firing/un-firing muscle groups in perfect sequence.

I bet there are many more reasons possible, one thing I'm sure of however is that in Mandrins model whether correct or not, the proximal segments acting solely under gravitational pull cannot be actively exerting any reverse torque on the joints!

.

 

[Deadly_Scope]

Btw., Deadly_Scope, you can stop chewing your popcorn. Regrettable perhaps, but the show is finished.

Regrettable perhaps, but at the same time can understand the necessity to edit and strip the thread back to the more substantive posts.

Next time i'll get hotdogs

 

[jake2]

Some more comments on the kinetic chain

The resulting graphs for a 2m long chain, same masses, are virtually identical to that shown in Figs 1, 2 and 3, albeit taking less time to accomplish. The peak tip velocity is, for this case, 136 miles/hour instead of 332 miles/hour. Hence much higher velocity than your guess, there being a reduction of maximum tip velocity of only 2.4 times instead of your guess of 16 times less.

That is interesting. If that's correct, it would indicate to me that the mass distribution in the chain has more to do with the velocity generation that the length of the chain.

The tip itself has very little mass, unlike a club, where the head weighs more than the shaft.

I also thought that for the head-ball collision (impact) momentum would be more relevant than kinetic energy, since that is what needs to be conserved. Momentum is a vector, so it has a direction. Any comment on that?

Contracting muscles, producing torque, indeed do power the swing. Gravity is minor contributor in a full fledged swing.

Big muscles are those of the legs, thighs, back and shoulders. They used the assumption that 1/8 horsepower is produced by a single contraction of a large muscle.

For that reason it's a bit hard to understand your comment about these other guys being wrong and that the kinetic chain is a power source.
I would guess it has to do with how much these big muscles have to do work and how efficiently the kinetic energy can be transferred from one segment to another. But, the kinetic chain itself cannot generate anything, it just transfers what was already generated (by gravity in your example).

Common sense tells us that the relevant muscles should not be relaxed. There has to be a definite tautness to be able to transmit torque and hence kinetic energy from hips to shoulders.

Hips can have there motion started and arrested slightly in advance of the shoulders.

In the kinetic chain from feet to clubhead, the shoulders are simply more distal relative to hips by their position in this kinetic chain.

By position, you mean timing?

I do not have any proof for this but my hypothesis is that getting tail bone ahead of neck bone in the downswing is a factor of making this part of the chain work efficiently.
If you'd keep rotating around the same axis back and forward, the only kinetic energy and momentum transfer happens with muscles acting like springs (x-factor stretch?). Is this really the only thing there?

 

[Brian Manzella]

I do not have any proof for this but my hypothesis is that getting tail bone ahead of neck bone in the downswing is a factor of making this part of the chain work efficiently.

No doubt.

But...

Here are the ANSWERS to my rhetorical questions from a few pages back:

What are the 3D machine measuring?

Sensors are placed on the body in various locations.

The machine measures how much the shoulder turn, hips turn, how much and what kind of side-bending is occurring, etc.

But it also measures the speed of these segments.

It does all of this in "Real-Time."
​

Why does Sergio's chain snap better than Funk's?

Because he uses his body more effectively to transfer the speed from one body segment to the other, helping created lots of hand speed, and with the help of his "snapping" of his power generating angles, clubhead speed.
​

When I throw a club, why don't I finish "all the way around" like when I hit a ball?????

Because you DO NOT rotate all the way to the finish.

You rotate to just past release, and when holding on to club, the club will pull you to the finish.
​

Why do pulls go farther than pushes, even with similar path vs. clubface vs. loft numbers?

Because swinging "across" your left leg, makes slowing the hips and then the shoulders and transferring their speed into the clubhead, easier than swinging "away" from your left leg.
​

Why does Lindsay Gahm's tee shots go so far with nearly a full sweep release?

Effective use of her Kinetic Chain.
​

 

[golfspike]

Which 3D machine are you getting your information from and what software are they using...which company?

 

[Bronco Billy]

Thanks for the Couragous and Informative Post... There are Two Sides to Every Coin...

Brian, I spoke to Dr. Zick about snapping a kinetic chain in the golf swing and he replied that it would not be advantageous to have anything big or bigger slow down or stop in the golf swing in order to make something smaller go faster. He said that it is necessary to create a negative torque on the handle of a bullwhip after you have applied a positive torque to it in order for the tail of the whip to crack or snap. He mentioned snapping a towel as another example. I may have misunderstood him but I'm pretty sure he described whipcracking and towel snapping as examples of a kinetic chain snap and strongly implied that good golfswings are not examples of kinetic chain snaps as you should never attempt to apply a negative torque on the handle of a golf club to snap the clubhead through impact because your arms and hands would not just need to slow down or stop to do so but would need to rapidly reverse their travel.

I'm a golf instructor with an English degree who realizes that most words have many meanings and many words are interpreted differently depending on one's culture, background, and experience. Are whipcracking and towelsnapping examples of snapping a kinetic chain? I understand in pictures and I picture hurting myself in the hands-wrists- forearms area should I attempt to apply a true whipcrack negative torque snap on a golf club that I just propelled toward the ball.

Another area I'm confused about is your example of some loose object on your dashboard picking up speed when your car slows or stops. I always thought that if a car going 60mph suddenly stopped, then that object on the dashboard would just keep going the same 60mph it was going before the car stopped. The object can't pick up speed unless something like another car collides head on with the 60mph car. If the other car is going 50 mph you'd really see that dashboard object pick up some speed! I believe this head on collision would be another example of a negative torque being applied to a positive torque. Is the head on collision causing the object to pick up speed an example of a kinetic chain snap or is the car just stopping and the object maintaining its speed the correct example? Are they both examples of kinetic chains? I don't know. Perhaps someone can help me because I'm getting quite confused about this whole kinetic chain thing.

I usually find out from more educated sources that I'm about half right or half wrong when I verbalize my latest theories about what happens or should happen concerning the physics of good golfswings so please take the following words with a grain of salt:

I generally believe that the legs are the engine of the golf swing and the arms, hands, and club are the muscular transmission system that forcibly harnesses and redirects the engine's energy into the ball. Basically the legs push into the ground for a fraction of a second with more weight pressure than the golfer actually weighs. The ground then pushes the same amount of energy back up through the feet and into the golfer. The golfer then - a fraction of a second after the push - sets or readies his on plane harness of geometrically advantaged arms, hands, and club to then muscularly unleash that groundforce into the ball. The body has just become a very brief but instantaneous conduit of energy from the ground up through the body and out of the upper extremities. Even the hands muscularly unhinge to redirect this energy into the ball. The hands unhinge at about the same time as the bent right arm unhinges but because they unhinge faster than the bent right arm they unleash their energy to propel the club before impact leaving the slower right arm to keep up the propulsion of the whole system through the ball. Of course the hands need to unhinge in an effective way for this to occur. Homer Kelley describes a very good way for the hands to unhinge. The torso complements the golfer's desire to unharness this energy to and through the ball by turning enough so the golfer can do it well. The torso in this way then adds energy to the inside of the upper left arm to help things along as well. The whole groundforce energy production, harnessing, delivering, and releasing is carried out by muscles. Once the swing is over, the whole batch of that initial groundforce energy has been seamlessy unleashed out of the extremities and the only muscular energy the golfer has left over is that which keeps him upright and at ease.

I know other forces - chiefly centripetal - are at work to make the swing divert into a circular or elliptical motion, but the causative force to move a clubhead to strike a golf ball well is muscular. I only hope I'm at least half right.

Brian, I really enjoy the opportunity to debate and hopefully not argue about the greatest game of them all. Keep being a pioneer and I'll remain a trustworthy ally and supporter. Thanks and go Gators and Tigers over the Bulldogs, and go Tigers and Gators on to the SEC championship game! What the hell, go any SEC team on to win the BCS championship so somebody can try to knock them off next year!



As to your

.

 

[Brian Manzella]

Try THIS coin:

If Coop found someone who HE THOUGHT did what he just said, he would find out quickly that when measured they did what I SAID.

I understand how people react to the TRUTH when it is a paradigm buster, just like the 11° inside-out crowd.

Dr. Zick probably wasn't asked the question correctly, btw.

 

[Guitar Hero]

No doubt.

But...

Here are the ANSWERS to my rhetorical questions from a few pages back:

What are the 3D machine measuring?

Sensors are placed on the body in various locations.

The machine measures how much the shoulder turn, hips turn, how much and what kind of side-bending is occurring, etc.

But it also measures the speed of these segments.

It does all of this in "Real-Time."
​

Why does Sergio's chain snap better than Funk's?

Because he uses his body more effectively to transfer the speed from one body segment to the other, helping created lots of hand speed, and with the help of his "snapping" of his power generating angles, clubhead speed.
​

When I throw a club, why don't I finish "all the way around" like when I hit a ball?????

Because you DO NOT rotate all the way to the finish.

You rotate to just past release, and when holding on to club, the club will pull you to the finish.
​

Why do pulls go farther than pushes, even with similar path vs. clubface vs. loft numbers?

Because swinging "across" your left leg, makes slowing the hips and then the shoulders and transferring their speed into the clubhead, easier than swinging "away" from your left leg.
​

Why does Lindsay Gahm's tee shots go so far with nearly a full sweep release?

Effective use of her Kinetic Chain.
​

The 3-D machines that TPI are using are missing measurement of torque from the muscular force to the club head. They have not figured out how to do this yet. When they do they will have an eye opening experience. Until then it is just their numbers for the pivot power.

There is more torque and power applied to the club head from muscular force in the upper body and arms than the pivot. Their staff is way behind when it comes to the golf swing and may never catch up. Don’t be fooled by the TPI name.

They are still searching and charging the desperate golfer to pay for it. Work outside the box of TPI, PGA and TGM and you will improve guaranteed. Their theories are flawed and will slow your progress.

 

[mandrin]

That is interesting. If that's correct, it would indicate to me that the mass distribution in the chain has more to do with the velocity generation that the length of the chain.

The tip itself has very little mass, unlike a club, where the head weighs more than the shaft.

jake2, I have been very explicit that the 8 segment kinetic chain is meant primarily to explain to as many posters possible the fundamental action of a kinetic chain. It is not meant in any way to represent a a golf swing. Nevertheless let me note that the length of the chain and the mass distribution both strongly effect the angular momentum.

I also thought that for the head-ball collision (impact) momentum would be more relevant than kinetic energy, since that is what needs to be conserved. Momentum is a vector, so it has a direction. Any comment on that?

Why do you think momentum is more important that kinetic energy? Given a certain mass, optimizing one is optimizing the other. One can analyze impact using momentum or kinetic energy leading to identical results. Using momentum is more elegant.

For that reason it's a bit hard to understand your comment about these other guys being wrong and that the kinetic chain is a power source.
I would guess it has to do with how much these big muscles have to do work and how efficiently the kinetic energy can be transferred from one segment to another. But, the kinetic chain itself cannot generate anything, it just transfers what was already generated (by gravity in your example).

Basically it is the following. Imagine a big mass and a small mass moving peaceful together and the small mass gallantly suddenly transferring all its energy to its big neighbour, there will be virtually no change. However when the biggy gives, graciously, in a short time interval, all its kinetic energy to the tiny one, it all of a sudden takes of like a rocket.

In a kinetic chain with multiple elements, especially when distal elements progressively lighter in mass, this transfer takes place over various elements till there is eventually a large built up of kinetic energy available for the last one element, free to express its joy receiving all this energy, hence move liking mad, being only connected at one end.

Therefore formulated differently, it has nothing to do with creating new energy but all with the re-distribution of existing kinetic energy. Hence in a kinetic chain a proximal segment can be considered locally as a source of power, even if overall the inertial interaction of all segments is a neutral energy mechanism. I will come back on this topic in detail eventually.

By position, you mean timing?

I do not have any proof for this but my hypothesis is that getting tail bone ahead of neck bone in the downswing is a factor of making this part of the chain work efficiently.
If you'd keep rotating around the same axis back and forward, the only kinetic energy and momentum transfer happens with muscles acting like springs (x-factor stretch?). Is this really the only thing there?

Muscles basically are not acting like springs - they produce kinetic energy by contracting and thereby setting bones/masses, to which they are connected , into motion.

 

[jake2]

[/INDENT]Why does Sergio's chain snap better than Funk's?

Because he uses his body more effectively to transfer the speed from one body segment to the other, helping created lots of hand speed, and with the help of his "snapping" of his power generating angles, clubhead speed.
​

When I throw a club, why don't I finish "all the way around" like when I hit a ball?????

Because you DO NOT rotate all the way to the finish.

You rotate to just past release, and when holding on to club, the club will pull you to the finish.
​

Why do pulls go farther than pushes, even with similar path vs. clubface vs. loft numbers?

Because swinging "across" your left leg, makes slowing the hips and then the shoulders and transferring their speed into the clubhead, easier than swinging "away" from your left leg.
​

Why does Lindsay Gahm's tee shots go so far with nearly a full sweep release?

Effective use of her Kinetic Chain.
​

This has been useful discussion from my point of view. Here's what I think right now. Pardon the high-school physics level, but I do not want to even try to go beyond that.

In theory what matters are:
#1 forces one can generate from the muscles
#2 directions of the forces
#3 how long distances the forces are applied

This determines the total work done and total kinetic energy generated.
The forces should be applied so that velocity is generated to the right direction. Wrongly applied forces can also cause breaking so all work does not necessarily generate kinetic energy.

Relevant distance could be considered to be from the top of backswing to impact. In theory, the longer the backswing the more kinetic energy can be generated with the same force. But for the big muscles, it's a function of shoulder turn, not arm swing. If right arm force is added only after the shaft is the last time vertical, the arm swing length beyond certain point is not that important.

And then #4
How efficiently the kinetic energy all this work has generated is transferred down in the kinetic chain to generate clubhead velocity.

Snapping the chain is a bit misleading in my opinion, because some people can do an efficient sweep release too. So, it's not how quickly the transfer happens, but the efficiency of the energy and momentum transfer down the chain.

You do not have to actively slow down a segment for the energy/momentum transfer to happen. All you need is to stop accelerating or reduce the rate of acceleration enough (i.e. stop applying force or reduce the amount of force enough) and the kinetic energy transfer to the next segment kicks in slowing the previous segment down.

Past impact the the chain goes on reverse and kinetic energy and momentum transfer back to the body, pulling it around.

 

[Guitar Hero]

This has been useful discussion from my point of view. Here's what I think right now. Pardon the high-school physics level, but I do not want to even try to go beyond that.

In theory what matters are:
#1 forces one can generate from the muscles
#2 directions of the forces
#3 how long distances the forces are applied

This determines the total work done and total kinetic energy generated.
The forces should be applied so that velocity is generated to the right direction. Wrongly applied forces can also cause breaking so all work does not necessarily generate kinetic energy.

Relevant distance could be considered to be from the top of backswing to impact. In theory, the longer the backswing the more kinetic energy can be generated with the same force. But for the big muscles, it's a function of shoulder turn, not arm swing. If right arm force is added only after the shaft is the last time vertical, the arm swing length beyond certain point is not that important.

And then #4
How efficiently the kinetic energy all this work has generated is transferred down in the kinetic chain to generate clubhead velocity.

Snapping the chain is a bit misleading in my opinion, because some people can do an efficient sweep release too. So, it's not how quickly the transfer happens, but the efficiency of the energy and momentum transfer down the chain.

You do not have to actively slow down a segment for the energy/momentum transfer to happen. All you need is to stop accelerating or reduce the rate of acceleration enough (i.e. stop applying force or reduce the amount of force enough) and the kinetic energy transfer to the next segment kicks in slowing the previous segment down.

Past impact the the chain goes on reverse and kinetic energy and momentum transfer back to the body, pulling it around.

You are on the right track! The back swing or height of the right hand only needs to be shoulder high. Any more is wasted motion. GH

 

[Brian Manzella]

Go read a little, and call me in the morning.

The 3-D machines that TPI are using are missing measurement of torque from the muscular force to the club head...

I am not big TPI fan.

I am a big SCIENCE fan.

I am a big "learn whatever I can to know more and out teach the competition" fan.

The higher-end 3D machines are VERY accurate.

The Kinetic Chain is a LARGE SOURCE of power.

It is NOT the only sourse, the hands and arms can exert MUCH FORCE across the shaft and thusly speed up the clubhead.

The best way to do that would be a good debate in another thread.

You "earth is flat" kinetic chain haters need to read these.

 

[Brian Manzella]

Exactly what are effective throwing mechanics? -- The Hardball Times

 

[2mongoose]

Brian, cool link. Regarding figure 2, there are two arms connected to the circle. The first arm rotates in perfect sequence with the circle, while the second pivots around a pin and is "thrown out" as the chain snaps.

Couldn't arm 1 be the arms, perhaps above the elbow, in relation to the core as a golfer pivots on the downswing and arm 2 be the forearms, with the wrists as the last pivot point?

I guess the idea is that the amount of snap is greatest when the angle between arm 1 and arm 2 is the most acute. Arm 1 would be to the right of the blue line, arm 2 "lagging" behind. The greater the angle the more the pivot would have to slow to be able to square the clubhead at impact.

My point is that if the above is anywhere near true shouldn't your arms and core always be in sync to be able to provide as much chain snapping umph as possible?

 

[Kevin Shields]

Exactly what are effective throwing mechanics? -- The Hardball Times

Now you're talking my language. Shoulders and arm on the same plane.