Post by imperfectgolfer on Jan 17, 2024 17:21:19 GMT -5
A few posts back I posted an essay-length argument to demonstrate that any clubface closure that happens relative to the clubhead path during the downswing is causally correlated to the amount of counterclockwise lead forearm rotation (supination) that happens between P6 => P7 (and mainly between P6 => P6.5), and I also demonstrated that the amount of counterclockwise trail forearm rotation that happens between P6 => P7 is minimal and that it cannot be casually correlated with the amount of counterclockwise clubface rotation relative to the clubhead path that is happening between P6 => P7.
I will now provide further reasoning/evidence that I am correct.
Note that TR states that an on-top trail hand grip is a face-opener grip, and that the trail arm/hand must be providing a clubface-closing phenomenon during the downswing in order to counter that clubface-opening effect. He expands on that clubface-closing phenomenon by stating that the clubface-closing action must start from the very start of the downswing as the trail palm starts to push the club handle downwards. Then, amazingly, he quotes Sasho MacKenzie between the 38:50 - 39:20 minute of the video when he states that when the trail palm is pushing the club handle down the hand arc path towards the ground between P4 => P6 that it is applying an "about-the-face" torque that will twist the clubshaft about its longitudinal axis during that time period in a counterclockwise direction. If TR is correct, then there should be evidence of the clubface closing phenomenon relative to the clubhead path happening between P4 => P6 and there should be evidence that the trail forearm is rotating counterclockwise during that time period to a degree that can be correlated with the degree of clubface-closing relative to the clubhead path.
So, lets examine the P4 => P6 downswing action of a prototypical on-top golfer - Angel Cabrera.
Angel Cabrera downswing action between P4 => P6.
I will now provide further reasoning/evidence that I am correct.
Consider what TR states between the 38:21 - 39:33 minute time point of this video.
Note that TR states that an on-top trail hand grip is a face-opener grip, and that the trail arm/hand must be providing a clubface-closing phenomenon during the downswing in order to counter that clubface-opening effect. He expands on that clubface-closing phenomenon by stating that the clubface-closing action must start from the very start of the downswing as the trail palm starts to push the club handle downwards. Then, amazingly, he quotes Sasho MacKenzie between the 38:50 - 39:20 minute of the video when he states that when the trail palm is pushing the club handle down the hand arc path towards the ground between P4 => P6 that it is applying an "about-the-face" torque that will twist the clubshaft about its longitudinal axis during that time period in a counterclockwise direction. If TR is correct, then there should be evidence of the clubface closing phenomenon relative to the clubhead path happening between P4 => P6 and there should be evidence that the trail forearm is rotating counterclockwise during that time period to a degree that can be correlated with the degree of clubface-closing relative to the clubhead path.
So, lets examine the P4 => P6 downswing action of a prototypical on-top golfer - Angel Cabrera.
Angel Cabrera downswing action between P4 => P6.
Capture images 1:
Capture images 2: (cropped images of the above capture images which allows one to see the clubface orientation relative to the clubhead path more distinctly).
Image 1 is at P4, image 2 is at P4.5, image 3 is at P5, image 4 is at P5.2, image 5 is at P5.5 and image 6 is at P6.
At P4 (image 1) you can see that AC's clubface is ~10 degrees closed relative to the back of his lead hand (which is slightly cupped), and which is expected because he uses a neutral lead hand grip. Note that his clubface is wide open relative to his clubhead path by ~60 degrees.
Note that at P4.5 (image 2) that AC does not bow or cup his lead wrist more so his clubface is still closed relative to the back of his lead hand by ~10 degrees. Note that his clubface is still open to his clubhead path to the same degree and his clubface is not closing more relative to his clubhead path.
Note that at P5 (image 3) that AC does not bow or cup his lead wrist more so his clubface is still closed relative to the back of his lead hand by ~10 degrees. Note that his clubface is still open to his clubhead path to the same degree and his clubface is not closing more relative to his clubhead path.
Note that at P5.2 (image 4) that AC does not bow or cup his lead wrist more so his clubface is still closed relative to the back of his lead hand by ~10 degrees. Note that his clubface is still open to his clubhead path to the same degree and his clubface is not closing more relative to his clubhead path.
Note that at P5.5 (image 4) that AC is palmar flexing his lead wrist to a small degree while he is supinating his lead forearm to a small degree and that combined biomechanical action will cause the clubface to close relative to his clubhead path by a very small amount. Note what is happening with respect to his trail forearm and trail palm between P5.2 => P5.5 - note that his trail forearm is becoming increasingly supinated which will rotate his trail palm more clockwise (and not counterclockwise). If the trail palm is rotating in a clockwise direction it will apply a "torque" to the club handle that is clockwise (and not counterclockwise) which means that it cannot possibly be applying a handle twisting effect in a clubface-closing (counterclockwise) direction.
Note that at P6 (image 1) that the clubface is tilted minimally towards the ground and it is not facing toe-up, and that the very small degree of clubface-closing relative to the back of his lead hand and relative to his clubhead path that exists at P6 is due to the "combined early lead forearm supination + lead wrist palmar flexion" maneuver that happened between P5.2 => P6. It cannot be causally due to any trail forearm rotary motion in a counterclockwise direction, because the trail forearm is rotating in the opposite clockwise direction (secondary to the fact that his trail forearm is increasingly supinating between P5 => P6).
These observations disprove TR's claim that the trail forearm's motion between P4 => P6 causes the club handle handle to twist in a counterclockwise direction, The amount of clubface-closing relative to the clubhead path that is happening between P4 => P6 is very small and it is causally due to the very small degree of combined "early lead forearm supination + lead wrist palmar flexion) action that happens in the early phase of the mid-downswing.
At P6, the clubface is still significantly open to the clubhead path, and the clubface-closing action needed to close the clubface relative to the clubhead path so that it becomes square by impact happens between P6 => P7, and mainly between P6.5 => P7.
Angel Cabrera's late downswing action
Image 1 is at P6, image 2 is at P6.5 and image 3 is at impact.
Note that the back of his lead hand is rotating counterclockwise between P6 => P7 mainly due to a lead forearm supination phenomenon, and that most of the counterclockwise rotation of the lead forearm happens between P6.5 => P7 - and that causes his clubface to close relative to his clubhead path so that it can become square by impact. During that time period, his trail forearm is always supinated and only slightly less supinated at P7 relative to P6 - so it cannot be causally responsible for the large amount of club handle twisting in a counterclockwise direction that is happening between P6 => P7.
Phil Cheetham did his PhD dissertation paper on the topic of factors related to the handle twist velocity phenomenon in pro golfers.
Here are two graphs from his paper.
The top graph shows the degree of club handle twist velocity in a counterclockwise direction (measured as angular velocity). The bottom graph shows the angular velocity of lead forearm supination.
The green vertical release line represents the start of the club release phenomenon (lead wrist uncocking phenomenon) which usually starts between P5.2 = P5.5 in most pro golfers. Note that there is no counterclockwise handle twist happening before the twist release point, which probably happens at ~P5.5.
Note that the slow phase of handle twist velocity in a counterclockwise direction happens in the yellow-colored zone, and the vertical green/violet arrows shows how it correlates with the slow angular velocity of lead forearm supination (blue graph) happening during that same time period. Note how the lead forearm supination velocity increases rapidly after the vertical violet arrow, and that causes the handle twist velocity to reach its peak counterclockwise rotational velocity in the later downswing (probably between P6.5 => P7).
So, Phil Cheetham has clearly shown that there is a direct correlation between the speed of lead forearm supination happening in the late downswing just before impact and the speed of handle twist velocity in a counterclockwise direction.
Phil Cheetham did not study the trail forearm's rotary motion in his research study and try to correlate it to the handle twist velocity because he was obviously smart enough to know that there is no reason to believe that there is a direct causal connection.
Jeff.