mandrin
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Weight shift is usually thought to be induced by a lateral motion of the lower body, it can however have various causes. Let’s have a closer look at weight shift in a golf swing.
Weight shift
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golfbulldog
New
Help please...
Figure 5 ... the total dynamic weight increases ( to near maximum... but not quite) when the rotating arm is vertical.
This would appear to be the "low point " of this robot's swing? Maybe
This increase in "dynamic weight" is different to Homer Kelley's "effective mass"?? probably??
You have said before that the mass of the clubhead does not increase during swing ... but the weight does?? ( but mass is consatnt... and g is constant??)
Also you used the comparison of differing weighted "iron byrons" in previous discussion ( maybe tungsten byron... the big "heavy set" member of the Byron family... everyone thinks that he should be a hitter but he wants to swing...) can you expand on this with respect to your weight transfer discussion please.
Figure 5 ... the total dynamic weight increases ( to near maximum... but not quite) when the rotating arm is vertical.
This would appear to be the "low point " of this robot's swing? Maybe
This increase in "dynamic weight" is different to Homer Kelley's "effective mass"?? probably??
You have said before that the mass of the clubhead does not increase during swing ... but the weight does?? ( but mass is consatnt... and g is constant??)
Also you used the comparison of differing weighted "iron byrons" in previous discussion ( maybe tungsten byron... the big "heavy set" member of the Byron family... everyone thinks that he should be a hitter but he wants to swing...) can you expand on this with respect to your weight transfer discussion please.
mandrin
New
Figure 5 ... the total dynamic weight increases ( to near maximum... but not quite) when the rotating arm is vertical.
This would appear to be the "low point " of this robot's swing? Maybe
This increase in "dynamic weight" is different to Homer Kelley's "effective mass"?? probably??
You have said before that the mass of the clubhead does not increase during swing ... but the weight does?? ( but mass is consatnt... and g is constant??)
Also you used the comparison of differing weighted "iron byrons" in previous discussion ( maybe tungsten byron... the big "heavy set" member of the Byron family... everyone thinks that he should be a hitter but he wants to swing...) can you expand on this with respect to your weight transfer discussion please.
golfbulldog,
Weight is really the force of gravitation on the surface of the earth. However, in an elevator standing on two weight scales there will be an increase or decrease of the readings due to the additional positive or negative acceleration introduced by the elevator. We have here a mix of the concepts of gravitational mass and of inertial mass, which however are not distinguishable.
For rotation this is quite similar. The clubhead weighs about 0.2 kg on a scale. If we introduced a ‘weight’ measuring device in the shaft of a driver one measures a much, much larger weight during a swing due to the centripetal acceleration. This is very similar to the situation of the elevator.
I know that these concepts of weight and mass are rather confusing. But if you think in terms of force it is easier to ‘digest’ these concepts. Mass is always constant independent of the circumstances. However it is the force exerted on or by the mass which can vary. This force is either due to the gravitational force field or due to the inertial forces created by motion of the mass.
In every day we use apparent weight or dynamic weight such as in an elevator or golf swing. We might for instance say that the apparent weight of the clubhead is about 100 lbs at impact for a pro type swing but one could also mention, perhaps more scientific, the magnitude of the centrifugal force exerted on the golfer by the clubhead.
For impact one has to distinguish two axes of interest, red axes along the shaft and the green one for impact. Along the shaft there is a very large centrifugal/centripetal force. Either you talk here in terms of apparent weight/mass or in terms of force. Along the green axes we have during the 0.0004 sec of impact a ‘free’ mass exerting a very large inertial force on the ball. No reason to use apparent/dynamic weight here.
Hence, during impact there is a definitely a constant mass. But there are exerted on the clubhead, a force by the clubshaft, a gravitational force towards the centre of the earth, a large centripetal force along the shaft and a large inertial force along the line of impact. One constant mass, but four forces.
mandrin
New
why shift weight?
Screening the WEB for some information on weight shift in a golf swing one typically finds:
-1-" Knowing how to release your stored-up energy (torque or coil), at the top of the backswing, is the least talked about subject in golf. "
-2- "The main reason for this idea of a weight shift in golf is because there is one in other sports. -- The reason a quarterback or tennis player's lower body shifts is because he took his arm back in the correct position, not the other way around."
-3- "Proper weight shift is necessary to hit the long ball. Learning a proper weight shift will add 10 yards or more to your shots."
-4- "In summary, what you have learnt from this information is that having a 'weight transfer' assists in positioning your body to generate large torques and thereby initiate the range of rotation that eventually results in fast club head speeds."
-5- "What happens here is that the right side is shifting to the left in the downswing to allow the right elbow to move far enough to the left, towards the ball, to be in a position to act as a pivot for the right forearm."
-6- "Weight transfer is a foundation to the dynamics found in your golf swing that produces additional power and enhances accuracy. "
-7- "A proper weight shift accomplishes two important things:
First, it supports and complements the rotation of the upper body and the swinging of the arms.
Next, it helps ensure that the club strikes the ball from the correct direction or path, as well as angle of approach."
It is quite interesting to see from above that weight shifting is associated with position, as a complimentary action, increasing the accuracy of ball striking and not just as a power move by itself.
We should not forget that weight shift is not simply a lateral movement to and fro along the target line. It is also caused by rotation of the arms and the body.
If one takes the view that a golf swing is to be treated as kinetic chain than one likely considers the various form of weight shift as a means to allow the heavier body segments participate fully in a golf swing.
However, the golf swing has a virtual center somewhere in the upper body. Shifting the body therefore not only shifts weight but also directly bears on the position of the swing center, and moving this center appropriately during the down swing can increase the clubhead speed.
Also some consider the position of the trail elbow prior to impact to be important and view the lateral motion of the body target wise as being necessary to allow the trail elbow to obtain its correct position to function optimally as the swing center just prior and through impact.
It would be quite interesting and very useful to hear from the real experts on this forum, who teach golf for a living, their views on weight shift in a golf swing.
Screening the WEB for some information on weight shift in a golf swing one typically finds:
-1-" Knowing how to release your stored-up energy (torque or coil), at the top of the backswing, is the least talked about subject in golf. "
-2- "The main reason for this idea of a weight shift in golf is because there is one in other sports. -- The reason a quarterback or tennis player's lower body shifts is because he took his arm back in the correct position, not the other way around."
-3- "Proper weight shift is necessary to hit the long ball. Learning a proper weight shift will add 10 yards or more to your shots."
-4- "In summary, what you have learnt from this information is that having a 'weight transfer' assists in positioning your body to generate large torques and thereby initiate the range of rotation that eventually results in fast club head speeds."
-5- "What happens here is that the right side is shifting to the left in the downswing to allow the right elbow to move far enough to the left, towards the ball, to be in a position to act as a pivot for the right forearm."
-6- "Weight transfer is a foundation to the dynamics found in your golf swing that produces additional power and enhances accuracy. "
-7- "A proper weight shift accomplishes two important things:
First, it supports and complements the rotation of the upper body and the swinging of the arms.
Next, it helps ensure that the club strikes the ball from the correct direction or path, as well as angle of approach."
It is quite interesting to see from above that weight shifting is associated with position, as a complimentary action, increasing the accuracy of ball striking and not just as a power move by itself.
We should not forget that weight shift is not simply a lateral movement to and fro along the target line. It is also caused by rotation of the arms and the body.
If one takes the view that a golf swing is to be treated as kinetic chain than one likely considers the various form of weight shift as a means to allow the heavier body segments participate fully in a golf swing.
However, the golf swing has a virtual center somewhere in the upper body. Shifting the body therefore not only shifts weight but also directly bears on the position of the swing center, and moving this center appropriately during the down swing can increase the clubhead speed.
Also some consider the position of the trail elbow prior to impact to be important and view the lateral motion of the body target wise as being necessary to allow the trail elbow to obtain its correct position to function optimally as the swing center just prior and through impact.
It would be quite interesting and very useful to hear from the real experts on this forum, who teach golf for a living, their views on weight shift in a golf swing.
golfbulldog
New
good question Mandrin
Brian teased us some months ago asking why most pros return to the elbow plane at impact... not sure he gave an official answer...
But the on plane right forearm is a standard alignment in TGM...
Wait and see what the pros say about it.
Homer liked it , i think, as a support for impact deceleration ( something that you feel is not possible/required in clubhead-ball impacts - i think)...
Thing is it occurs naturally in so many great swings that it must be an "effect" from swinging well rather than be a "cause" of great impact.... is that what you thinking Mandrin?
PS thanks for the fully worded teaching session on your diagrams - good stuff!
Brian teased us some months ago asking why most pros return to the elbow plane at impact... not sure he gave an official answer...
But the on plane right forearm is a standard alignment in TGM...
Wait and see what the pros say about it.
Homer liked it , i think, as a support for impact deceleration ( something that you feel is not possible/required in clubhead-ball impacts - i think)...
Thing is it occurs naturally in so many great swings that it must be an "effect" from swinging well rather than be a "cause" of great impact.... is that what you thinking Mandrin?
PS thanks for the fully worded teaching session on your diagrams - good stuff!
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mandrin
New
golfbulldog,
Is it not intriguing that many golf books tell you in detail how to go about weight shifting yet, if it was not for you, not a single soul seems to have any interest in discussing the subject.
Yet it seems to be essential in a golf swing.Could it be that this is symptomatic in general for much golf instruction, lots of practical details about how but no reasons given why? There have been by many instructors endlessly studying of video and slowly the ”effect” seems to take the place of the “cause”, to borrow your succinct statement.
Good thing Brian has stirred the pot a bit with his last video, lately not much debate or argument going on. There is nevertheless birdie_man who admits that getting to find out things sounds like a lot of work and fears a “cranium explosion”!
I don’t think that it is really so dramatic. Mandrin
You said...However, the golf swing has a virtual center somewhere in the upper body. Shifting the body therefore not only shifts weight but also directly bears on the position of the swing center, and moving this center appropriately during the down swing can increase the clubhead speed.
Where would you guess is that virtual center?
You said...However, the golf swing has a virtual center somewhere in the upper body. Shifting the body therefore not only shifts weight but also directly bears on the position of the swing center, and moving this center appropriately during the down swing can increase the clubhead speed.
Where would you guess is that virtual center?
mandrin
New
joeparr,
For a golfer there are two shoulder segments, a lead arm segment and the trail upper arm and forearm segments which together determine the trajectory of the hands around the body. The virtual swing center however can be determined from the trajectory of the hands as illustrated in Fig1.
It can be done graphically by drawing several normals to the curve. The swing center is given by the point of intersection of these normals to the curve. For a circle this will results in one single point. For other curves, deviating from a circle, this is not the case and one has a curve, the evolute, locus of centres of curvature.
Prof. T. Jorgensen and others have used this method in the past to determine, using high speed stroboscopic photographic means, the trajectory of the hands and subsequently from it the effective center of the swing.
As you can see illustrated (much exaggerated) in the figure someone with a lateral slide, flattens his swing and will give an elliptical touch to the hands trajectory and the virtual swing center will move likely a bit outward and behind the golfer at the bottom of the swing.
birdie_man
New
There is nevertheless birdie_man who admits that getting to find out things sounds like a lot of work and fears a “cranium explosion”!
Don't you worry mandrin....I'm still here......will be around for a good while.
I'll stick my foot into this when something sticks out at me.
mandrin
New
To round off an exciting debate just some additional tidbits about weight shift.
-8- Some claim that weight transfer, to and fro, is done to put the body weight appropriately over either one of the two axes used to pivot around in a golf swing.
-9- Some put forward the idea that there is not really a net weight shift but rather an upper body moving back and a lower body forward, maintaining dynamic balance.
-10- Others however opinion that the upper and lower body centers should remain vertically stacked in a golf swing.
-11- We also have now Mike Weir claiming that weight shift is not important, in his new ‘less-transfer swing’.
-12- In ‘gravity golf’ however proper weight ‘shifting’ is considerd to constitute the very essence of a golf swing..
Golf is indeed interesting with its large kaleidoscope of ideas and illusions.
-8- Some claim that weight transfer, to and fro, is done to put the body weight appropriately over either one of the two axes used to pivot around in a golf swing.
-9- Some put forward the idea that there is not really a net weight shift but rather an upper body moving back and a lower body forward, maintaining dynamic balance.
-10- Others however opinion that the upper and lower body centers should remain vertically stacked in a golf swing.
-11- We also have now Mike Weir claiming that weight shift is not important, in his new ‘less-transfer swing’.
-12- In ‘gravity golf’ however proper weight ‘shifting’ is considerd to constitute the very essence of a golf swing..
Golf is indeed interesting with its large kaleidoscope of ideas and illusions.
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Michael Jacobs
Super Moderator
Joe Norwood
Mandrin,
Interesting that link study in the first post had a reference at the end to Joe Norwood - His book Golf -O- Metrics is one of my favorites - old but great - Never heard anyone reference it before --- very cool
Mandrin,
Interesting that link study in the first post had a reference at the end to Joe Norwood - His book Golf -O- Metrics is one of my favorites - old but great - Never heard anyone reference it before --- very cool
mandrin
New
Michael, I agree, there is not a single golf instruction book quite like it.
Michael Jacobs
Super Moderator
I have a hard cover of golf o metrics, bought it at a library closing
Great Book!
Great Book!
shootin4par
New
mandrin,
could you give us an example of whose weight shift is what you would call "ideal" and then elaborate a little on what it is they do and how they do it? interesting topic, very important.
could you give us an example of whose weight shift is what you would call "ideal" and then elaborate a little on what it is they do and how they do it? interesting topic, very important.
Brian Manzella
Administrator
If it is "no shift at all" I'll buy you dinner. Neil.
If it is even CLOSE to the Kool-Aid Tripod, I'll buy you lunch.
Mandrin, we are looking for OPTIMUM FORCE!
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