Sasho Mackenzie's latest

[drewyallop]

http://people.stfx.ca/smackenz/Publications/MacKenzie%202012%20Club%20position%20relative%20to%20the%20golfer's%20swing%20plane%20meaningfully%20affects%20swing%20dynamics.pdf


There is a very interesting thread on this forum about "laying off" the club. Many opinions and points of view but I did not see any reference to this research on the subject. I just read the paper and anyone interested in the subject should read it too. Scientific yes but intuitively it makes sense. Most important it cuts through all the fog propagated by swing experts. Especially interesting was the irrelevance (under certain bounds) of flat vs. upright swing planes in making good impact.

There is valuable simplification here. I went out and tried to discover what people were talking about on the "laid off" thread with no success. I read this paper and immediately knew what laid off meant and how it related to the downswing. And, most important, how it organized and simplified the application of torques in the downswing.

I am always amazed that fruitless, uniformed debate continues on these topics when there is hard science available that , while not always conclusive, can at least focus the discussion on something more concrete than dogma or video "evidence". And I believe this research is more evidence that BM, MJ and associates are on to something very important. Read BM's tag line again. After reading this paper it starting to make even more sense.

 

[spktho]

Great find, thanks for posting that up. Especially like the conclusions that being steep in the beginning of the downswing leads to face squaring problems and that being underplane(laid off) early in the downswing will facilitate face squaring. He defines the swing plane as the plane traced by the lead hand then compares where the club is to that plane. This makes the hand path pretty important too.

 

[Robbierob99]

This Says it all

Conclusion
In conclusion, it was found that the positioning of the club relative to the plane traced out by the lead hand of the golfer can have a meaningful effect on the golfer’s ability to square the clubface for impact. Positioning the club below the golfer’s swing plane, early in the downswing, will facilitate the squaring of the clubface for impact, while positioning the club above the plane will have the opposite effect. It was also demonstrated that changing the steepness of the golfer’s swing plane does not appear to have any meaningful effect on the delivery of the clubhead to the ball.
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[Dariusz J.]

Interesting read. A beauty of EEP, early squaring of the face and no need to rapid closure in the impact zone as a consequence ? I believe YES.

Cheers

 

[Kevin Shields]

I hate to disagree, but his findings have been addressed here a lot. Perhaps he didn't get enough of the credit for his papers but we've said for awhile that a laid off shaft will result in a better squaring opportunity with good hand path. Negative beta before positive.

 

[drewyallop]

I hate to disagree, but his findings have been addressed here a lot. Perhaps he didn't get enough of the credit for his papers but we've said for awhile that a laid off shaft will result in a better squaring opportunity with good hand path. Negative beta before positive.

I agree with you Kevin. You and your colleagues have recommended this move often. But I had trouble understanding it in terms of negative and positive torques and, i may be wrong, but there are outstanding questions on things like should you lay off before or after transition, how much and so on. MacKenzie's paper talks about all this and, for me, makes the mechanics and implementation of the move clearer.

 

[spktho]

I hate to disagree, but his findings have been addressed here a lot. Perhaps he didn't get enough of the credit for his papers but we've said for awhile that a laid off shaft will result in a better squaring opportunity with good hand path. Negative beta before positive.

I too agree Kevin that this is exactly what you have been talking about, just didn't know there was a published paper on it.

 

[Mike Richardson]

On page 12 it says:

"In the absence of a forearm supination torque, the clubface can still be squared for impact if the club is below the golfer’s
swing plane at the start of the downswing."

Forearm supination torgue suggests tumble to me so is this saying that, if the club is below the plane, there's no need to tumble?

 

[natep]

I thought he said it just requires less torque, but I could be wrong. But yes, the general idea is that if you lay the club off and have a good hand path, the club will tend to come closer to "squaring itself up" automatically.

 

[Mike Richardson]

I thought he said it just requires less torque, but I could be wrong. But yes, the general idea is that if you lay the club off and have a good hand path, the club will tend to come closer to "squaring itself up" automatically.

Thanks, just been reading it again and it talks about "an angular impulse" which as you say suggests squaring itself. There's also a "moment arm" for the component of force which is the difference between the club and the swing plane. Do you or anyone know what a "moment arm" means?

A component of force acting within the arm abduction plane produces an angular impulse on the club about the longitudinal axis of the lead arm.

 

[SteveT]

Conclusion
In conclusion, it was found that the positioning of the club relative to the plane traced out by the lead hand of the golfer can have a meaningful effect on the golfer’s ability to square the clubface for impact. Positioning the club below the golfer’s swing plane, early in the downswing, will facilitate the squaring of the clubface for impact, while positioning the club above the plane will have the opposite effect. It was also demonstrated that changing the steepness of the golfer’s swing plane does not appear to have any meaningful effect on the delivery of the clubhead to the ball.

So can we agree that the reference "swing plane" is the one traced out by the lead hand ... and the club plane relative to the hand plane affects clubface squaring? Ideally, the shaft plane should be BELOW the hand plane but only early in the downswing.

This relationship is essentially also unaffected by the steepness of the hand plane... or is it?

Now this brings into question the repositioning of the club relative to the hands later in the downswing. Mike Jacobs observes there is an "under the table" positioning of the club relative to the lead arm, which means the club plane is ABOVE the hand plane going into impact!

So when should the club plane orientation change from BELOW to ABOVE the hand plane?

 

[Mike Richardson]

So can we agree that the reference "swing plane" is the one traced out by the lead hand ... and the club plane relative to the hand plane affects clubface squaring? Ideally, the shaft plane should be BELOW the hand plane but only early in the downswing.

This relationship is essentially also unaffected by the steepness of the hand plane... or is it?

Now this brings into question the repositioning of the club relative to the hands later in the downswing. Mike Jacobs observes there is an "under the table" positioning of the club relative to the lead arm, which means the club plane is ABOVE the hand plane going into impact!

So when should the club plane orientation change from BELOW to ABOVE the hand plane?

When the club gets below the hands?

 

[SteveT]

When the club gets below the hands?

Mackenzie calls it the "hand" plane... not hands. You figure it out.

 

[leon]

Mackenzie calls it the "hand" plane... not hands. You figure it out.

Pretty sure Mike meant after last parallel, i.e. when the clubhead is nearer the ground than the hands.

In any case, doesn't a steep club in transition, as defined in the paper, result in a clubhead that is below the hand plane at impact? Which would mean that conversely an initially below hand plane clubhead would end up above the hand plane?

What I find more puzzling is that the paper seems to be saying that for an initially below hand plane clubhead, no effort, at least in terms of forearm torque, is required to square the club. So what happens when you do apply some?

 

[ekennedy]

What I find more puzzling is that the paper seems to be saying that for an initially below hand plane clubhead, no effort, at least in terms of forearm torque, is required to square the club. So what happens when you do apply some?

 

[Mike Richardson]

Pretty sure Mike meant after last parallel, i.e. when the clubhead is nearer the ground than the hands.

In any case, doesn't a steep club in transition, as defined in the paper, result in a clubhead that is below the hand plane at impact? Which would mean that conversely an initially below hand plane clubhead would end up above the hand plane?

What I find more puzzling is that the paper seems to be saying that for an initially below hand plane clubhead, no effort, at least in terms of forearm torque, is required to square the club. So what happens when you do apply some?

Thanks for that, you put it far better than I did.

Your question is really interesting, it'll be interesting to see what the experts say.

 

[spktho]

What I find more puzzling is that the paper seems to be saying that for an initially below hand plane clubhead, no effort, at least in terms of forearm torque, is required to square the club. So what happens when you do apply some?

Apply positive torque="fore left"?

Apply negative torque= "fore right"?

 

[lia41985]

On page 12 it says:

"In the absence of a forearm supination torque, the clubface can still be squared for impact if the club is below the golfer’s
swing plane at the start of the downswing."

Forearm supination torgue suggests tumble to me so is this saying that, if the club is below the plane, there's no need to tumble?

Basically what Kevin once termed "automated squaring".

A. Putting slack in my swing at the top
B. Getting the shaft under the plane of the handpath in the downswing

Automated squaring, baby!

Slack so I can control not yanking the handle horizontally, i.e., so I can control my handpath.

Preparing the shaft under this hand route so it can automatically flop or tumble outward to the ball

 

[drewyallop]

Maybe this will help clear up some confusion. This is what I got from the paper:

There are two planes defined. The "golfer swing plane" which is the plane traced out by a point in the middle of the lead arm wrist bone. The second plane is the "club plane" which is traced out by a line connecting the end of the grip and the centre of the clubface.

There are several simulations tested but they fall into three categories:

1. club plane above golfer swing plane at the start of the downswing

2. club plane below golfer swing plane at the start of the downswing

3. club plane the same as golfer swing plane at the start of the downswing

All else being equal number 1 makes squaring the clubface difficult, is the main cause of an over the top downswing, and a slice producer.

Number 2 makes squaring much easier. In fact the simulation with no forearm supination torque squared the clubface as long as the club plane was below the golfer swing plane at the start of the downswing. The illustration showing the moment arm explains why. There is a force in the direction of the arrow which pulls clubhead up closer to the golfer swing plane. This is I think is the tumble feel.

Number 3 assumes that the golfer and club planes are the same at start down and that gravity immediately pulls the club plane below the golfer swing plane (reminds me of Kevin's advice to let the hands drop). At this point two alternatives were tested.

In the first case the golfer immediately applies forearm supination torque. In the second case forearm supination torque is applied mid-swing i.e. when lead forearm is parallel to ground (the magic position).

Early supination was found to be sub-optimum. Applying supination torque at the start of the downswing results in something like premature ejaculation. The work stops before the job is done. Angular momentum increases very quickly at the start of the downswing but quickly peters out to nothing before mid-swing is reached (MikeG may want to provide a graphic showing the peter-out effect).

On the other hand starting the supination torque mid-downswing allows a smooth build-up of angular momentum to just before impact. Interesting to note that Kevin's advice to let the arms drop also implies that the arms are passive and relaxed at start down, thus no early application of torque.

Other things I think are significant ...

The best clubhead velocity was achieved by starting the downswing with the club swing plane and the golfer swing plane equal, the club plane then dropping below the golfer swing plane, then the application of forearm supination torque at lead arm parallel. For me this exact timing of the torque application is most difficult. The instinct is to start torquing right away. Patience! Let the arms drop.

The highest velocity downswing (sim5) showed the club swing plane 11 degrees flatter than the golfer swing plane at impact c.f. Mike Jacobs under the table video.

Clubhead velocities were significantly higher when forearm supination torque was applied compared to the passive case of letting the club square itself. Active rotation of the forearm resulting from a muscular torque can contribute significantly to clubhead speed.

Finally this quote from the paper ...

"The relationship that any variable (e.g. weight shift, delayed release, or swing plane) has on the outcome of a golf swing (e.g. clubhead speed, path, or face angle) can be understood by determining how that variable affected the force and/or torque being applied to the club by the golfer."

Chew on that one for a while.

 

[spktho]

Nice synopsis Drew. That pretty much sums it up.

"...something like premature ejaculation." Don't remember that one though