Post by imperfectgolfer on Feb 20, 2024 13:08:02 GMT -5
Many analytical golfers cannot clearly understand how it is possible to rotate the lead forearm a lot between P6 => P7 without rotating the trail forearm by a similar amount.
Here is Jon Sinclair's graph of forearm rotation in pro golfers.
Here is Jon Sinclair's graph of forearm rotation in pro golfers.
The yellow zone represents the P6 => P7 time period. One can clearly see that the lead forearm is supinating a lot between P6 => P7 and it causes the club handle to twist counterclockwise (= "about-the-shaft" twisting phenomenon) while the club is being released, and that allows a pro golfer to square the clubface relative to the clubhead path by impact.
Note that there is minimal counterclockwise rotation of the trail forearm.
Many analytical golfers cannot understand how this is possible.
In the thread on Pete Cowen's swing ideology, Janik stated-: "Personally, I am still not settled on the theory that one can have significant rotation of the lead forearm whilst maintaining minimum rotation of the trail. I am also not comfortable with the terms supination and pronation as technically it is relative to the elbow joint, whereas to me the rate of rotation is more important and not the absolute position."
Note that he states that the "rate of rotation is important". Rate of rotation of "what"? Surely, we are not exactly interested in what biomechanical mechanism causes the rotation of "what" and we are mainly interested in the biomechanical mechanisms that cause rotation of the back of the lead hand and trail palm between P6 => P7.
Consider Angel Cabrera's rate of rotation of the back of his lead hand and trail palm between P6 => P7.1.
Image 1 is at P6, image 2 is at P6.5, image 3 is at P7, and image 4 is at P7.1.
I have drawn a red line down the middle of his trail antecubital fossa and a blue line along his trail lower forearm's radial bone. Note that his trail forearm is still supinated at P7 and P7.1 and that very little counterclockwise rotation of his trail forearm happened between P6 => P7.1.
Note that the back of his lead hand is parallel to the ball-target line at P6 and facing the target at P7.1, which means that it rotated ~90 degrees counterclockwise between P6 => P7.1. How is that accomplished biomechanically if the lead wrist does not significantly change its angle in the plane of lead wrist extension => flexion (= GFLW) during that time period - where the lead arm is angled about ~45 degrees away-from-the-target at P6 and perpendicular to the ball-target line at P7.1. The only rational answer from a biomechanical perspective is a significant amount of lead forearm supination.
Now consider his trail palm. It is facing the ball-target line at P6 and then facing the target at P7.1, which means that it has rotated ~90 degrees counterclockwise. How is that possible if he is not rotating his trail forearm counterclockwise by a significant amount between P6 => P7.1?
Look at his trail wrist at P6 - note that it is very extended and radially deviated. Note that his trail forearm is angled perpendicular to the ball-target line. Note that his trail palm is parallel to the ball-target line. Then, look at these trail forearm/wrist alignments at P7.1. Note that i) his trail forearm is angled about 45 degrees towards-the-target at P7.1 due to internal rotation of the trail humerus. Note that his ii) trail wrist has straightened a lot between P6 => P7.1. When the trail wrist straightens by a significant amount between P6 => P7.1, it can cause the trail palm to roll clockwise if the trail wrist moves in the direction of ulnar-deviation and it can cause iii) the trail palm to roll counterclockwise if the trail wrist moves in a radial direction. The combination of the three biomechanical phenomena - i) and ii) and ii) - allows the trail palm to rotate counterclockwise by ~90 degrees so that it faces the target by P7.1 without any need to rotate the trail forearm counterclockwise.
Jeff.