Post by imperfectgolfer on Feb 2, 2024 12:00:28 GMT -5
Sasho MacKenzie came up with an "idea" that if the clubshaft is shallowed relative to the hand arc path during the early-mid downswing that it will provide a pro golfer with an ability to passively perform a lead forearm supinatory motion in the later downswing and that it will decrease any active "about-the-shaft" torque needed to produce the "about-the-shaft" handle twisting phenomenon frequently seen in pro golfers (especially if they use a weak-or-neutral lead hand grip strength).
SMK and Chris Como discuss this issue in this video.
This is the image produced by SMK to make his point.
SMK and Chris Como discuss this issue in this video.
This is the image produced by SMK to make his point.
Note what he states under the image-" that a component of force acting within the arm abduction plane produced an angular impulse on the club about the longitudinal axis of the lead arm".
What effect will that "force" have on the club? As the diagram shows it will induce the clubshaft to move upwards in the direction of the lead arm abduction plane so that the clubshaft will be inclined to line up with the direction of that red arrow.
I do not dispute the logic of his claim (based on the laws of physics), but I think that it is of no relevance when it comes to explaining what is happening in a "real life" golf swing action of some pro golfers.
First of all, when a golfer is pulling the club handle down the hand arc path between P4 => P7 there may be another "force" in play that shallows the clubshaft between P4 => P6 so that the clubshaft never steepens between P4 => P6 (as suggested by that diagram). In fact, I know of no pro golfer who shallows the clubshaft in the early downswing between P4 => P5 and then steepens the clubshaft between P5 => P6. Most pro golfers who start to shallow the clubshaft between P4 => P5 will continue to shallow the clubshaft even more between P5 => P6.
SMK's secondary claim is that the practical value of shallowing the clubshaft between P4 => P6 is that it will diminish the "about-the-shaft" torque needed to square the clubface relative to the clubhead path, a phenomenon which usually happens in the later downswing between P6 => P7. That claim makes no sense to me and I will further analyse his claim.
If a golfer adopts a very strong lead hand grip, then the amount of "about-the-shaft" torque needed to square the clubface relative to the clubhead path between P6 => P7 is very small because the clubface is nearly square to the clubhead path by P6 (simply due to the fact that the clubface is already =/>60 degrees closed relative to the back of the lead hand at address).
Consider a golfer who uses a very strong lead hand grip - Matthew Fitzpatrick
Note that his clubface is >60 degrees closed relative to the back of his lead hand at P6 and it is nearly square to his clubhead path and it only has to close another ~20 degrees between P6 => P7 to be square to the clubhead path by impact.
Here are capture images of Matthew Fitzpatrick's P6 => P7 time period.
Image 1 is at address, image 2 is at P6, image 3 is at P6.5 and image 4 is at P7.
Note that his clubface is >60 degrees closed relative to the back of his lead hand at address and note that it is closed by the same amount at P6.
Note that there is minimal counterclockwise rotation of his lead hand happening (secondary to a PA#3 release action) between P6 => P7.
Therefore, there is no need for him to shallow the clubshaft between P4 => P6 in order to make it easier to square the clubface relative to the clubhead path between P6 => P7 - presuming that you believe that SMK's claim is true.
The "real life" reality is that many pro golfers, who use a very strong lead hand grip, arbitrarily/personally decide to shallow their clubshaft between P4 => P6.
Consider an example- Milo Lines.
Capture image of Milo Lines clubshaft shallowing action.
The red splined path is his hand arc path.
Image 1 is atP4, image 2 is at P4.5, image 3 is at P5, image 4 is at P5.2 and image 5 is at P5.5.
Note that ML shallows his clubshaft in his early downswing between P4 => P5, and even more in his mid-downswing between P5 => P5.5. Note that his clubshaft has shallowed groundwards from being on the TSP at P4 to becoming close to the elbow plane by P5.5.
Then, from P5.5 => P7 it remains close to the elbow plane - as seen in the images below (iron swing are images 1 and 2 and driver swing are images 3 and 4).
Image 1/3 is at P6 and image 2/4 is at P7.
I have drawn a red line down his lead arm and a yellow line down his clubshaft at impact, and the angular difference between the two lines represents the magnitude of his accumulator #3 angle at impact. Note that Milo prefers to have his lead arm more outstretched away from his body at impact when swinging a driver, and that results in a smaller accumulator #3 angle at impact.
Note that there has been minimal counterclockwise rotation of the back of his lead hand happening between P6 => P7 due to lead forearm supination - which makes sense because he uses a strong lead hand grip.
Milo may have personal/arbitrary reasons for why he prefers to shallow his clubshaft between P4 => P6, but it makes no sense to claim that the reason is that he needs to ensure that he needs to decrease the amount of active force required to perform a PA#3 release action between P6 => P7 (which is the basis of SMK's reasoning).
If you look at Milo's clubshaft in image 3 it is shallower than his lead arm abduction plane, and his clubshaft does move closer to his lead arm abduction plane between P6 => P7 (which means that the clubshaft can be conceived to being subjected, and responding, to the "component of force" as described in SMK's image).
Now, consider Sergio Garcia's clubshaft shallowing action.
The red splined path represents his hand arc path.
Image 1 is at P4, image 2 is at P4.5, image 3 is at P5, image 4 is at P5.5, image 5 is at P5.7, and image 6 is at P6.2.
Note that SG shallows his clubshaft a lot between P4 => P5 and slightly more between P5 => P5.7.
Note that the back of his lead hand is more horizontal at P5.5 (image 4) compared to P4 (image 1), which means that it is more pronated.
Note that SG is starting to supinate his lead forearm early between P5.7 => P6.2, which happens at a time when he still has a large clubhead lag angle (which means that his MOI relative to any "about-the-shaft" torque must be large). That means that SG needs to use more lead forearm supinatory force than usual - compared to a golfer (like Phil Mickelson) who only starts to supinate his lead forearm after P6.5 when PA#2 is already significantly released and when the MOI is going to be much smaller. What makes it biomechanically possible for SG to generate more active lead forearm supinatory force starting at ~P5.7 is the fact that his lead forearm is pronated, which means that his lead forearm supinatory muscles are more optimally pre-stretched and therefore biomechanically capable of generating more supinatory muscular force when they actively contract. I cannot understand SMK's argument that SG needs less lead forearm supinatory force as a result of his clubshaft shallowing action - and I think that the opposite fact is more likely to be true.
Consider another point. SMK argues that the clubshaft will tend to line up with the lead arm abduction plane due to a "component of force" that exists when the lead hand is pulling the club handle along the hand arc path. I can see/perceive that "passive phenomenon" happening in Milo Lines P5.5 => P7 time period when he is swinging a driver because his clubshaft is moving towards his lead arm abduction plane between P5.5 => P7 (as previously described). However, SG's clubshaft is moving in the opposite direction between P5.5 => P7 and it is moving in a more underplane direction (see image 6) away from his lead arm abduction plane, which is steepening due to the fact that his lead arm becomes more vertically-aligned between P5.5 => P7).
That means that SMK's predicted passive "component of force" factor is not seemingly in play in SG's later downswing action. As I have previously argued, it is more likely that SG has to use more lead forearm supinatory force than usual because he starts his lead forearm supinatory action much sooner when he still has a large clubhead lag angle, which should result in a larger MOI relative to any existing "about-the-shaft" torque force that could be in play.
Jeff.