Post by imperfectgolfer on Jan 4, 2023 10:39:09 GMT -5
Dr Mann
"Are you presuming that the lead arm and clubshaft have the same fulcrum point and that they are both moving on the same swingplane (FSP)?"
No, if there is a PA3 angle the hub path and club shaft swing planes will be different as you've explained above.
There are several methods from a mathematical perspective that can be used to measure the angular velocities of the lead arm and club. You've mentioned a method above using relative motions but that doesn't seem to be the method being used by the AMM 3D system. Whatever method they use should provide the same answers so the kinematic sequence graphs will still show the correct angular velocities of the lead arm and club. The graphs can still be used to compare the variance in the angular velocities of the lead arm/club at least up to impact but we still have problems with the accuracy post impact (because of the low frequency of the system measurements from P7-P7.2).
Looking at the graphs , there still has to be a significant reduction in the angular velocity of the club (even taking into the account the decrease caused by clubhead/ball impact) to match the lead arm angular velocity from P7-P7.2 (ie. DH-hand release action).
DG
I suspect that we cannot rely on the accuracy of the club's angular velocity measurements post-impact.
Look at these graphs.
Note how the brown graph goes up-and-down (like a yo-yo) during the post-impact phase.
Common sense dictates that the club is not abruptly accelerating-decelerating-accelerating again in such a short time period (eg as seen in JB Holmes graph).
Here is Sasho MacKenzie's one-arm swing action.
Here are capture images from that video.
Note that the clusbhaft remains straight-line-aligned with his lead arm to well beyond P7.4. Surely that means that they are traveling at the same angular velocity. Ask Phil Cheetham that question.
Jeff.