Post by imperfectgolfer on Jul 12, 2023 22:43:25 GMT -5
Dr Mann
What if JB was using his lead triceps muscle to actively extend his elbow in the downswing? Wouldn't that increase clubhead speed over a straighter arm if the extension was timed perfectly?
Phil Cheetham didn't mention how the forearm is released , whether due to a mechanism like the 'in plane MOF' that releases PA#2 or by musculature triceps contraction or a bit of both.
We do know that active wrist torque in the downswing can be detrimental to clubhead speed unless the timing is perfect , so does the same apply to an active triceps release of the lead forearm?
If we look at the kinematic sequence graphs again for Rory vs JB , JB's maximum pelvis/thorax angular velocities are inferior but his max forearm angular velocity is similar to Rory's straight arm angular speed. How can that be?
Somehow, JB is able to do similar linear work on the club as Rory but with a bent lead elbow, where his hands traverse over a smaller downswing path. Rory's straighter lead arm means he has more width in his downswing and his hands travel over a longer hand path.
Therefore, for JB to do similar linear work (via his hands on the grip) as Rory, he will have to apply, on average, a greater linear force along a smaller hand path. How can he generate a larger average linear force in the downswing if has an inferior upper/lower pivot angular velocity than Rory? I suspect he could be using his shoulder girdles more actively to generate larger hand forces on the grip or actively using his lead triceps to help release his forearm, or a bit of both.
DG
You asked-: "What if JB was using his lead triceps muscle to actively extend his elbow in the downswing? Wouldn't that increase clubhead speed over a straighter arm if the extension was timed perfectly?"
Not if the angular velocity of lead forearm motion is no faster than what would happen if a standard PA#4 release action releases a straight lead arm very efficiently so that the lead hand speed at P5.5 is the same.
You wrote-: "Somehow, JB is able to do similar linear work on the club as Rory but with a bent lead elbow, where his hands traverse over a smaller downswing path. Rory's straighter lead arm means he has more width in his downswing and his hands travel over a longer hand path."
A straighter lead arm does not necessarily cause a hand arc path that is wider because one also has to factor-in the position of the lead shoulder socket at every moment between P4 => P5.5, which depends on other biomechanical factors like the degree of lead scapula protraction and the degree of upper torso tilt.
You asked-: " How can he generate a larger average linear force in the downswing if has an inferior upper/lower pivot angular velocity than Rory? I suspect he could be using his shoulder girdles more actively to generate larger hand forces on the grip or actively using his lead triceps to help release his forearm, or a bit of both."
You have correctly answered your own question.
Jeff.