Post by dubiousgolfer on Apr 15, 2021 20:31:01 GMT -5
I've always been confused by Jorgensen's paradox as explained in DT's website. DT has no concept of PP1 so he may not have noticed how it could assist with negative torque and increase clubhead speed .
Here are extracts from DT's website concerning 'Lessons from the Double Pendulum Model' and I've highlighted some very counterintuitive aspects.
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Wrist torque ("hand action") affects clubhead speed at impact in a very surprising way. So much so, in fact, that Jorgensen refers to it as "The Paradox".
Here is the essence of what he found:
The good golfer he measured used just enough wrist torque just long enough to maintain the initial wrist cock angle until inertial forces started throwing the club outward. That typically takes .1-.15 seconds. After that, the golfer used no wrist torque at all! Jorgensen recalls a gem from Bobby Jones' instructions that the club feels like it is "freewheeling through the ball."
So the paradox: any wrist torque during the downswing that aids release will result in a lower clubhead speed at impact. Oh, it will indeed increase the clubhead speed through most of the downswing. But you don't care about that; you want the maximum clubhead speed you can get at impact. And using hand action to release the clubhead works against that aim.
In fact you can increase the clubhead speed at impact by using a hindering hand action. This is paradoxical, counterintuitive -- but the model says it is true. And I know at least one instructor who gets very good results teaching a hand action that tries to hold the wrist cock right through impact -- a swing key that creates a hindering torque.
I have written a whole article devoted to Jorgensen's paradox, in case you want to look deeper into it.
I did one more mini-study with SwingPerfect. Because of things discovered later in this article, I wanted to answer the question:
Suppose the golfer is exercising retarding torque for most of the downswing. We know this produces more clubhead speed. But... Would releasing this negative torque just before impact increase the clubhead speed further?
This tells us that negative wrist torque is a good thing for clubhead speed. By itself, it gives more than a 5% increase in clubhead speed, enough for a gain of about 17 yards. We knew it would give us an improvement, but that's big.
Releasing that negative wrist torque 70 milliseconds before impact buys us a tiny bit more clubhead speed -- but not enough for even one more yard. Definitely not worth learning. And if you do your release too early, you lose that gain and a lot more
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Therefore , unless I have misinterpreted the above, somehow trying to optimise the negative torque throughout the downswing from P4-P7 can assist in the generation of more clubhead speed (or more likely maintain or 'limit any decrease' in clubhead speed).
So if you look at the effect of the PP1 force when the club is moving into forward bend , the PP1 force is actually assisting more 'negative torque' . Look at image below where the shaft is in forward bend, the blue arrow is the PP1 force while the black arrows are the 'reactive forces' of the fingers on the grip (because the clubshaft is actually pulling on the right hand during PA#2 release) .
One can see that the PP1 and black arrow reactive finger forces are creating a negative torque around the 'Mid-Hand Point' (the red dot).
I think I understand the physics why a negative torque will result in an increase in clubhead speed but that depends on other factors such as the 'In Plane Net Force' magnitude and direction from release to P7. Basically , when 'Release' happens the 'moment arm' starts to rapidly decrease , therefore the MOF effect will progressively decrease unless you are able to do the following:
1. Increase the magnitude of the 'In Plane Force'
2. Increase the 'moment arm'
3. Do both 1 and 2 .
I think a 'negative' torque prevents a rapid decrease in the 'moment arm' while allowing the golfer time to increase the magnitude of his 'In Plane Net Force' . If the golfers rate of increase of 'In Plane Net Force' is greater than the rate of decrease of the 'moment arm' , then there will be on average a greater MOF being applied which will increase clubhead speed.
Now all I have to do is prove it!!!!
DG
Here are extracts from DT's website concerning 'Lessons from the Double Pendulum Model' and I've highlighted some very counterintuitive aspects.
-----------------------------------------
Wrist torque ("hand action") affects clubhead speed at impact in a very surprising way. So much so, in fact, that Jorgensen refers to it as "The Paradox".
Here is the essence of what he found:
The good golfer he measured used just enough wrist torque just long enough to maintain the initial wrist cock angle until inertial forces started throwing the club outward. That typically takes .1-.15 seconds. After that, the golfer used no wrist torque at all! Jorgensen recalls a gem from Bobby Jones' instructions that the club feels like it is "freewheeling through the ball."
So the paradox: any wrist torque during the downswing that aids release will result in a lower clubhead speed at impact. Oh, it will indeed increase the clubhead speed through most of the downswing. But you don't care about that; you want the maximum clubhead speed you can get at impact. And using hand action to release the clubhead works against that aim.
In fact you can increase the clubhead speed at impact by using a hindering hand action. This is paradoxical, counterintuitive -- but the model says it is true. And I know at least one instructor who gets very good results teaching a hand action that tries to hold the wrist cock right through impact -- a swing key that creates a hindering torque.
I have written a whole article devoted to Jorgensen's paradox, in case you want to look deeper into it.
I did one more mini-study with SwingPerfect. Because of things discovered later in this article, I wanted to answer the question:
Suppose the golfer is exercising retarding torque for most of the downswing. We know this produces more clubhead speed. But... Would releasing this negative torque just before impact increase the clubhead speed further?
This tells us that negative wrist torque is a good thing for clubhead speed. By itself, it gives more than a 5% increase in clubhead speed, enough for a gain of about 17 yards. We knew it would give us an improvement, but that's big.
Releasing that negative wrist torque 70 milliseconds before impact buys us a tiny bit more clubhead speed -- but not enough for even one more yard. Definitely not worth learning. And if you do your release too early, you lose that gain and a lot more
----------------------------------------------------------------------------------
Therefore , unless I have misinterpreted the above, somehow trying to optimise the negative torque throughout the downswing from P4-P7 can assist in the generation of more clubhead speed (or more likely maintain or 'limit any decrease' in clubhead speed).
So if you look at the effect of the PP1 force when the club is moving into forward bend , the PP1 force is actually assisting more 'negative torque' . Look at image below where the shaft is in forward bend, the blue arrow is the PP1 force while the black arrows are the 'reactive forces' of the fingers on the grip (because the clubshaft is actually pulling on the right hand during PA#2 release) .
One can see that the PP1 and black arrow reactive finger forces are creating a negative torque around the 'Mid-Hand Point' (the red dot).
I think I understand the physics why a negative torque will result in an increase in clubhead speed but that depends on other factors such as the 'In Plane Net Force' magnitude and direction from release to P7. Basically , when 'Release' happens the 'moment arm' starts to rapidly decrease , therefore the MOF effect will progressively decrease unless you are able to do the following:
1. Increase the magnitude of the 'In Plane Force'
2. Increase the 'moment arm'
3. Do both 1 and 2 .
I think a 'negative' torque prevents a rapid decrease in the 'moment arm' while allowing the golfer time to increase the magnitude of his 'In Plane Net Force' . If the golfers rate of increase of 'In Plane Net Force' is greater than the rate of decrease of the 'moment arm' , then there will be on average a greater MOF being applied which will increase clubhead speed.
Now all I have to do is prove it!!!!
DG