Getting the hands more forward at P6

[utahgolfer]

Hi Dr Mann and DG, happy holidays.

Is the distortion in the brown line immediately after impact due to the collision of the club head with the ball? Aside from this, is the fastest point of the forward swing at impact, with club head speed slowing down after this? Do you think the brown line would gradually decrease after impact, with no distortion, during a practice swing using no ball? Is the main reason the swing slows down post-impact due to the lead shoulder rotating slightly up and away from the target?

Thanks!

UG

[dubiousgolfer]

Hi UG - Happy holidays too.

I would imagine it would be optimal if a golfer maximised clubhead speed at impact and yes, I think impact with ball causes a lot of distortion after impact (not sure how sensors used in 3D measurements react during impact). I haven't seen a 3D graph of a golf swing without a ball but maybe Sasho Mackenzies new 'stack system' device (which seems to be quite popular at the moment) might produce some clubhead speed graphs for swings with no ball impact.



If you look at the kinematic sequence graph from Phil Cheetham's website , it seems that there is a temporary speeding up of the 'ribcage/lead arm/pelvis' post impact and that's because the club is losing energy which is being transferred back to the golfer. To slow the club down (from an angular velocity perspective) would require a negative torque being applied via the hands on the grip but I wouldn't know which main muscles are actively involved or in what sequence . Obviously , there could also be net linear forces being applied to the club to also slow it down , but to explain it all would probably be quite complex (well outside my area of knowledge).

DG

[imperfectgolfer]

DG,

You wrote-: "If you look at the kinematic sequence graph from Phil Cheetham's website , it seems that there is a temporary speeding up of the 'ribcage/lead arm/pelvis' post impact and that's because the club is losing energy which is being transferred back to the golfer."

I disagree! I do not believe that any energy is being transferred from the club post-impact back to the golfer.

First of all, the clubhead speed may decrease temporarily by 20% due to ball collision, but that does not mean that the lead arm//hands/proximal clubshaft is slowing down in DHers by that amount.

Here is a speed graph measured by Rob Neal.

Note that hand speed does not drop immediately post-impact (eg. between P7 => P7.05)

Note that lead arm speed starts decreasing pre-impact, but that there is a plateau immediately pre/post impact where lead arm speed remains relatively constant.

Note that there is no temporary increase in pelvic/UT speed immediately post-impact.

Jeff.

[dubiousgolfer]

Dr Mann

Yes, I agree there is no transfer of energy from the club to the golfer immediately post impact , but a little later when the golfer slows the club down.

DG

[imperfectgolfer]

Dec 12, 2021 12:35:06 GMT -5 dubiousgolfer said:

Dr Mann

Yes, I agree there is no transfer of energy from the club to the golfer immediately post impact , but a little later when the golfer slows the club down.

DG

I don't think that the club ever transfers energy to the golfer when is slow down in the later followthough because the club is not an active agent producing energy. If the club slows down in the later followthrough, it must surely be because the golfer is not applying enough energy to keep it moving.

Jeff.

[dubiousgolfer]

Dec 12, 2021 15:18:16 GMT -5 imperfectgolfer said:

Dec 12, 2021 12:35:06 GMT -5 dubiousgolfer said:

Dr Mann

Yes, I agree there is no transfer of energy from the club to the golfer immediately post impact , but a little later when the golfer slows the club down.

DG

I don't think that the club ever transfers energy to the golfer when is slow down in the later followthough because the club is not an active agent producing energy. If the club slows down in the later followthrough, it must surely be because the golfer is not applying enough energy to keep it moving.

Jeff.

The club still has kinetic energy after impact and slows down (which means less kinetic energy) . The only way its kinetic energy can be lessened  is :

1. A transfer of Kinetic Energy to  'gravitational potential energy'  as the club's COM mass moves to a higher position in the follow-through
2. Loss of energy to friction with air
3. Internal friction within the club (as it deforms)
4. Energy transferred via the hands to the golfer as the club is actively slowed down. 

I suspect 1-3 is quite small compared to 4  

For example , lets say  there is a loose rope with one end tied to the back bumper of a car , the other end tied to a motionless person (ie. who would have zero kinetic energy) .  The car is started and accelerated to a small velocity, then the engine switched off while the rope is still loose . As the car continues to move at that constant small velocity, the rope stretches taut , it pulls on the car slowing it up but also pulls on the person giving him/her motion.  The car's kinetic energy is less while the person's kinetic energy has increased which shows there is a transfer of kinetic energy from the car through the rope to the person.

The same can be said of the tension in the shaft in the follow-through , it pulls on the club's COM but also pulls on the golfer via his hands. That's how energy is transferred between hands and the club's COM  (in either direction).

Rod White explained this phenomenon on Tutelman's website to explain how energy is transferred in a double-pendulum and it still applies in the follow-through but in the opposite direction (ie. from the club to the golfer via the hands).

----------------------------------------------------



The figure shows a ‘stroboscopic’ view of the golf swing. Have a close look at the direction of the clubhead midway through the swing – this is indicated approximately by the red arrow. Now look where the hands move at the same time – the blue arrow: in a different direction!

Obviously the hands and clubhead cannot continue to move in different directions, they are restrained by the fixed length of the shaft. The diverging directions of the club and hands results in a large tension in the shaft.

The tension pulls against the club head causing it to accelerate, and pulls against the hands causing them to decelerate. It is the differing directions of the hands and club that are ultimately responsible for the energy transfer.

------------------------------------
DG

[imperfectgolfer]

In your example, energy may move from the club to the hands, but all that energy originally came from the active hands.

Jeff.

[janik]

I think I have made a self discovery on the topic of getting to P6 with the hands more toward the target ie not early releasing.

For it to work, one must then have the concept of working the hand path, and thus club shaft, inwards toward the body from P6. “Exit left” is now a term that make sense to me.

[imperfectgolfer]

Jan 12, 2022 4:36:15 GMT -5 janik said:

I think I have made a self discovery on the topic of getting to P6 with the hands more toward the target ie not early releasing.

For it to work, one must then have the concept of working the hand path, and thus club shaft, inwards toward the body from P6. “Exit left” is now a term that make sense to me.

I think that the term "exit left" really applies to the post-impact time period if a golfer chooses to use a CP-arm release action. However, one should not think of "exiting left" prematurely at P6 because it can induce a "tumbling action" and a hand arc path that is out-to-in between P6 => P7, which can cause the clubshaft to move inwards towards the body. The hands should move roughly parallel to the stance line between P6 => P7, and the clubshaft should be moving downplane along the functional swingplane so that the clubhead can move in-to-out as the club releases between P6 => P7.

Here is Dustin Johnson's late downswing action.

The red plane line represents the functional swingplane.

Note that his hands are just in front of his toe line at P6, and that his hands do not move inward closer to his body between P6 => P7.

Note that his clubshaft remains on the functional swingplane between P6 => P7 and it does not move closer to the body, and that that allows the clubhead to move in-to-out between P6 => P7.

Jeff.

[dubiousgolfer]

Dr Mann

I am confused from a geometry perspective how a golfer (with a PA3 angle at impact) can still square the clubface at impact with an intact LFFW, while still being able to have the 'whole' clubshaft moving on the functional plane from P6-P7.

DG

[janik]

Thanks, Dr. Mann.

I guess it is all relative to an individual golfer. Previously, my hands were actually moving right as in ball ward. With a feeling of them rounding the corner I now have shaft lean. Something I have been chasing for 2 years.

After my epiphany I found this video that explains exactly my previous symptoms and the ‘fix’ that worked for me.

youtu.be/6CQelE-75Og

[janik]

Jan 12, 2022 11:33:02 GMT -5 dubiousgolfer said:

Dr Mann

I am confused from a geometry perspective how a golfer (with a PA3 angle at impact) can still square the clubface at impact with an intact LFFW, while still being able to have the 'whole' clubshaft moving on the functional plane from P6-P7.

DG

Me too, I think it is camera angles.

See this video also of DJ: his hand path goes seriously left from P6 to impact:

youtu.be/v8lh6Ct-32U

Also see McIlroy with driver:
youtu.be/P3YksJdejog
If his hand path didn’t move in towards his body from P6 to P7 he would either miss the ball or hit the heel.

[imperfectgolfer]

Jan 12, 2022 11:33:02 GMT -5 dubiousgolfer said:

Dr Mann

I am confused from a geometry perspective how a golfer (with a PA3 angle at impact) can still square the clubface at impact with an intact LFFW, while still being able to have the 'whole' clubshaft moving on the functional plane from P6-P7.

DG

DG - I don't know why you have a problem envisioning how the clubshaft can remain on the functional swingplane between P6 => P7.

Here is a capture image of a pro golfer (Zach Johnson) practicing with a plane board.

Note that the clubshaft is lying against the surface of the plane board at P6 (image 1), at P6.5 (image 2) and at impact (image 3).

Note that his hands are moving roughly parallel to the planeboard between P6 and P7, and that they are not moving closer to his body.

Here is a video showing how the clubshaft can remain on the plane board (= functional swingplane) between P6 => P8 - watch the video between the 1:55 => 2:35 minute time points.

Note that his hands are not moving closer to his body between P6 => P7 and his hands are moving roughly parallel to the surface of the plane board.

Janik - note that Dustin Johnson's hands are moving parallel to his foot stance in that video, It looks like his hands are moving inwards between P6 => P7 but that impression is due to the camera angle where his foot stance is open relative to the camera angle. Relative to his open foot stance, his hands are moving roughly parallel to his foot stance alignment.

Here are capture images from that video.

Note that his foot stance and clubshaft angle at P6 (image 1) is angled leftwards due to the camera angle.

Note that his hands are moving parallel to that leftwards-angled foot stance alignment between P6 => P7.4 (image 3) and he is not really "exiting left".

Here is another camera angle showing the P6 => P7 time period.

Note that his hands do not move closer to his body between P6 => P7.

Here is another set of capture images showing that DJ's hands do not "exit left" post-impact.

Jeff.

[dubiousgolfer]

Dr Mann

Yes , I was looking at videos of those planeboards before I posted my comment. I'll see if I can post some images later this evening to demonstrate my confusion.

DG

[janik]

Dr. Mann,

Would you therefore disagree with this video from Chris Ryan regarding hands position:

youtu.be/4vkgd8GUtAI

Also, here are more examples of pro golfers with a inward hand path from P6 to P7:
youtu.be/02imCuJAZCw
youtu.be/EmLyMDyCbto

I can find lots more that don’t have the foot line too far off the camera angle.