Golf Physics - Why the DST Golf Training Aid Clubs Fail

[Vinsk]

2 hours ago, Divot Tool said:

The best ball strikers who ever lived utilized lag pressure and knew when to release it.

I think you’re running with an idea with this term ‘lag pressure/tension’ which you’ve yet to explain the physics of. No offense to Bertie here but he’s apparently taken some views of pros where some have more shaft lean than others, slapped a ‘physics sounding’ term to it and created a bit of a pseudo-scientific device. 

And honestly I’m not impressed when a pro uses a training aid. Many times if not most pros don’t really know the mechanics or physics behind a golf swing. They can be easily sold on a device just because they like it and not really have much idea as to how it really works. And let’s face it, these guys don’t really need training devices for things such as impact. They’re impact is consistently damn good.

It would be a great discussion to read/listen to between Bertie and Erik. But as an outsider and much, much less educated reader on the subject, Erik has made points with physics explanations and you’ve really just used vague explanations with some undefined terms. 

 

[Divot Tool]

4 hours ago, Vinsk said:

I think you’re running with an idea with this term ‘lag pressure/tension’ which you’ve yet to explain the physics of. . . 

I would define Lag Pressure as the increasing pressure you feel in the right index finger (PP3) imparted by the shaft as a result of the handle leading the clubhead as it approaches impact.

On that note. . . Do you think that great ball strikers of the game could explain the exact physics of the golf swing in order to strike it well?  They understood the swing in terms of feels, pressures and visual concepts.  They didn't have Trackman, Bodi-trak, Swing Catalyst etc. to quantify things for them.  

Cordle's research has 96% of all golfers reaching full extension before ball contact.  You think it's merely a coincidence that the majority amateur golfers-who don't exactly flush it-dump all lag pressure before contact? Do you think it's a coincidence that the vast majority of professional players-who stripe it-produce and retain lag pressure into impact?  I don't think it's a coincidence. . .and neither does Bertie Cordle.  That very premise is the foundation of the DST compressor.  

 

5 hours ago, Vinsk said:

 No offense to Bertie here but he’s apparently taken some views of pros where some have more shaft lean than others, slapped a ‘physics sounding’ term to it and created a bit of a pseudo-scientific device. 

That's called 'observation' and its often employed in scientific Method. 

[Divot Tool]

6 hours ago, iacas said:

No.

If they weren't producing lag pressure, are you implying that the best ball strikers to ever play the game 'flipped' at the ball?  We'll just leave this here because it's not even debatable.  

 

6 hours ago, iacas said:

Fred Couples had a cupped lead wrist at impact (still does). Jordan Spieth and Lee Westwood do/did too. Plenty of great ball strikers have had arched left wrists, too.

Freddie Couples may have employed a strong grip but he surely did NOT have a cupped lead wrist at impact. . . he surely wasn't flipping the club at the ball.  That's absolutely false.   

 

6 hours ago, iacas said:

The club shaft straightens out when you swing it at a certain speed.

As a result of you reaching full extension before impact.  

 

6 hours ago, iacas said:

The DST is a visual-only training aid. 

And yet you have countless Tour pros using it voluntarily at tournaments to replicate feels, develop proprioception and kinesthetic awareness while hitting balls.  

5 hours ago, Vinsk said:

. . .No offense to Bertie here but he’s apparently taken some views of pros where some have more shaft lean than others, slapped a ‘physics sounding’ term to it and created a bit of a pseudo-scientific device. 

Big difference between shaft lean and lag pressure btw. 

[Vinsk]

6 hours ago, Divot Tool said:

Big difference between shaft lean and lag pressure btw. 

Ok, what is it? How is lag pressure measured? Why does Koepka have ‘tons’ and JT only have ‘ a lot’? 

[boogielicious]

13 minutes ago, Vinsk said:

Ok, what is it? How is lag pressure measured? Why does Koepka have ‘tons’ and JT only have ‘ a lot’? 

Come on @Vinsk ! Lag pressure is explained by this simple equation! All the kids are using it!

[Vinsk]

9 hours ago, Divot Tool said:

Freddie Couples may have employed a strong grip but he surely did NOT have a cupped lead wrist at impact.

But he has ‘negative lag pressure’ right? Which is described as ‘disastrous’.

[amished]

10 hours ago, Divot Tool said:

I would define Lag Pressure as the increasing pressure you feel in the right index finger (PP3) imparted by the shaft as a result of the handle leading the clubhead as it approaches impact.

On that note. . . Do you think that great ball strikers of the game could explain the exact physics of the golf swing in order to strike it well?  They understood the swing in terms of feels, pressures and visual concepts.  They didn't have Trackman, Bodi-trak, Swing Catalyst etc. to quantify things for them.  

Cordle's research has 96% of all golfers reaching full extension before ball contact.  You think it's merely a coincidence that the majority amateur golfers-who don't exactly flush it-dump all lag pressure before contact? Do you think it's a coincidence that the vast majority of professional players-who stripe it-produce and retain lag pressure into impact?  I don't think it's a coincidence. . .and neither does Bertie Cordle.  That very premise is the foundation of the DST compressor.  

 

That's called 'observation' and its often employed in scientific Method. 

If you look at a basketball close enough it appears flat.  Not all observations are correct, or relevant. 

While we're talking about pseudo-science, where do your data concerning "the majority of amateur golfers... dump all lag pressure before contact" from?  And what does that mean?  Does that mean 50.001% of amateur golfers do this?  100%?  And is "all" really all?  So they have no pressure at the point you specified?  Sorry, we deal with actual science here, so we're going to need proof about your claims.

[Vinsk]

10 hours ago, Divot Tool said:

I would define Lag Pressure as the increasing pressure you feel in the right index finger (PP3) imparted by the shaft as a result of the handle leading the clubhead as it approaches impact.

Lovely. Now where is the data showing how this pressure differs among players. Show me that data that measures this pressure from a good ball striker to a poor one. 

[iacas]

10 hours ago, Divot Tool said:

I would define Lag Pressure as the increasing pressure you feel in the right index finger (PP3) imparted by the shaft as a result of the handle leading the clubhead as it approaches impact.

I thought so. And that should be a clue as to why you're wrong.

Look, you're into TGM. That's fine, but man, those ideas are outdated. It's great that you can say PP3 and I know what you're talking about, but science has advanced since then. Homer himself would have been interested in the advances, and much of TGM would be very different now had he stayed alive.

Think about this: for every action, there's an equal and opposite reaction. By pushing against PP3, which is below the coupling point of the hands, you're actually more likely to THROW AWAY the lag you have. If you hold a club in your hands, how are you going to push at PP3? By flexing the trail wrist and extending the lead wrist.

Here's a lead arm and a club shaft. The coupling point is the red dot. If you apply a force at PP3 (where the arrow is pointing), in the direction of the arrow, it will lead to "throwing out the lag."

11 hours ago, Divot Tool said:

On that note. . . Do you think that great ball strikers of the game could explain the exact physics of the golf swing in order to strike it well?  They understood the swing in terms of feels, pressures and visual concepts.  They didn't have Trackman, Bodi-trak, Swing Catalyst etc. to quantify things for them.

What's the point of that paragraph? I'm honestly asking.

Because where I'm coming from, I get to rely on actual data, actual science, physics, math, biomechanics, etc. to know what is actually happening. Then I turn around and teach the "feelings" to people, because nobody's an actual robot, but it certainly helps to discuss what actually happens.

That's what I'm doing here.

If you're interested in talking about only what something feels like to you, I'm not interested, because I have no idea what something "feels like" to you, and I've had enough students tell me something feels almost the exact opposite of what they're actually DOING that I've settled on how pointless it is to discuss it when not in person.

11 hours ago, Divot Tool said:

Cordle's research has 96% of all golfers reaching full extension before ball contact.

If he actually had a sensor at PP3, he'd find a HUGE variation among Tour players and amongst average players. Of that 96%, some would have a great deal of "lag pressure" at PP3… because that's part of how they THROW away the lag.

Look, dude, we're in agreement that lining the shaft up at impact is important. It's Key #3 in the 5 Simple Keys®.

But the DST is a visual-only training aid. When swung at any real speed, the bend in the shaft disappears. Simple physics.

11 hours ago, Divot Tool said:

You think it's merely a coincidence that the majority amateur golfers-who don't exactly flush it-dump all lag pressure before contact?

They don't. A great many of them have more of what you're calling "lag pressure" at impact than PGA Tour players.

11 hours ago, Divot Tool said:

That's called 'observation' and its often employed in scientific Method. 

Science disagrees with your ideas about "lag pressure."

9 hours ago, Divot Tool said:

If they weren't producing lag pressure, are you implying that the best ball strikers to ever play the game 'flipped' at the ball?  We'll just leave this here because it's not even debatable.

How much "lag pressure" do you think Vijay, Freddie, and Phil have in the photos above?

How am I able to "lag" the club properly (and release it properly) holding it in just my left hand?

Here's how: the arms accelerate, which builds lag, and as the arms (and hands) slow down, the clubhead catches up, lines up, and then overtakes the lead arm.

That's it. That's all that really happens in the downswing. There are forces in all directions, too, but while the club shaft is increasing the angle between it and the left arm, there's actually more force on the FRONT of the right hand grip (on Vijay's right index finger) than on PP3, because that's the direction the shaft is trying to move. The hands are slowing down, and the shaft is catching up.

9 hours ago, Divot Tool said:

Freddie Couples may have employed a strong grip but he surely did NOT have a cupped lead wrist at impact. . . he surely wasn't flipping the club at the ball.  That's absolutely false.

I didn't say he flipped.

But his left wrist is definitely cupped. It's been measured, and you can see it plain as day in the images I posted.

10 hours ago, Divot Tool said:

17 hours ago, iacas said:

The club shaft straightens out when you swing it at a certain speed.

As a result of you reaching full extension before impact.  

Not remotely accurate. You're flat out wrong here, for reasons I've already explained, and you seem to have completely missed the part where Justin Rose is swinging it and it's straight when he hits it, too.

Here's a fact I think you're going to have trouble wrapping your brain around so long as you think PP3 matters like you think it does: the shaft of virtually every PGA Tour player is in FORWARD DEFLECTION at impact.

Just physics, man. This has been observed, explained, measured, captured, etc. It's a fact.

[iacas]

You can watch the videos in that topic.

BTW, I was reminded of this topic:

So, it's not like I didn't once "like" the idea of PP3. This topic dates back to almost a decade ago, though, and I've learned and grown quite a bit in that time, as has our overall understanding of what happens in a golf swing.

[Divot Tool]

On 9/6/2019 at 9:42 AM, Vinsk said:

But he has ‘negative lag pressure’ right? Which is described as ‘disastrous’.

 

Nice photo of impact, mind you it's clearly shot from an angle that diminishes the reality his optimal impact.  But feel free to be subjective about impact. 

 

Freddie had produced plenty of lag pressure and knew when to release it.  Guy is almost 60 years old and averages close to 300 yards. . .he sure ain't flipping it.  

 

 

 

[iacas]

3 minutes ago, Divot Tool said:

Nice photo of impact, mind you it's clearly shot from an angle that diminishes the reality his optimal impact.  But feel free to be subjective about impact. 

Oh brother.

3 minutes ago, Divot Tool said:

Freddie had produced plenty of lag pressure and knew when to release it.  Guy is almost 60 years old and averages close to 300 yards. . .he sure ain't flipping it.

You're apparently not reading what anyone is saying.

And again, high lag pressure would actually increase the odds of flipping for many people, as you're applying a force below the coupling point in the hands, which makes the shaft move through its arc sooner.

P.S. Your picture of Fred's impact position is from a pretty bad camera angle. Fred isn't hitting the driver out of the middle of his stance.

[Vinsk]

1 minute ago, Divot Tool said:

 

Nice photo of impact, mind you it's clearly shot from an angle that diminishes the reality his optimal impact.  But feel free to be subjective about impact. 

 

Freddie had produced plenty of lag pressure and knew when to release it.  Guy is almost 60 years old and averages close to 300 yards. . .he sure ain't flipping it.  

 

 

 

Again....nobody said he flips.

2 minutes ago, Divot Tool said:

Freddie had produced plenty of lag pressure and knew when to release it. 

And again...this is a pseudoscience based comment. You haven’t scientifically explained how your definition of ‘lag pressure’ works. You’re not reading/understanding what @iacas has posted. 

Your statements are like me saying, ‘ DJ hits the ball far because he has a lot of torque pressure applied to his sternum which creates powerful rotational force.’

It’s an idea for which I have no data, nor physics to support it. These tour pros are not superior ball strikers because of what they do with their right index finger.

[Divot Tool]

On 9/6/2019 at 11:34 AM, iacas said:

Think about this: for every action, there's an equal and opposite reaction. By pushing against PP3, which is below the coupling point of the hands, you're actually more likely to THROW AWAY the lag you have. If you hold a club in your hands, how are you going to push at PP3? By flexing the trail wrist and extending the lead wrist.Just physics, man. This has been observed, explained, measured, captured, etc. It's a fact.

I'm not debating the fact that the lag isn't thrown away. . it must be inevitably released.  All great ball hitters had lag pressure and understood HOW and WHEN to release it.  

All I'm saying the difference between the best ball strikers that ever lived and every the average weekend chop as Cordle illustrates is that they reach a straight line condition after impact and the average chop dumps it before impact.  It can not be any more clear. 

Are we really pushing at PP3, or is that pressure a result of the shaft loading? 

The technology that we are blessed with today was created from the need to quantify and thus comprehend why the BEST do what they do.  Force Plates, Bodi-Trak, Trackman, Gears et al don't make you a great ball stiker, they are merely tools.  

 

On 9/6/2019 at 11:34 AM, iacas said:

Look, dude, we're in agreement that lining the shaft up at impact is important. It's Key #3 in the 5 Simple Keys®.

Actually, no we're not in agreement here.  Great ball strikers don't reach a straight line condition until well after impact.  

 

Here's a photo of Vijay Singh that actually captures his impact conditions.  Looks familiar.  

 

Here's a photo of Couples at impact. No cupping here at impact.  Just a strong left hand grip.  If one were to look at the photo you posted above where the club is already parallel with the ground well past impact, one might come to the conclusion that he flipped it as the cupping suggests.  If the left wrist didn't cup post impact, he'd be hooking it off the planet.  Nonetheless, it's not cupped at impact because he's hasn't dumped his lag like the weekend chopper.  

 

On 9/6/2019 at 6:58 AM, Vinsk said:

Ok, what is it? How is lag pressure measured? Why does Koepka have ‘tons’ and JT only have ‘ a lot’? 

you should ask Bertie Cordle that and all the great ball strikers.  We're not trying to quantify it, merely acknowledging that it exists and there is a correlation between lag tension and it's importance with respect to impact.  We're not saying you have to have "x" amount of lag pressure to be Elite. . .that's a bit silly.

You are feel differently despite a history of great ball strikers effectively illustrating Bertie Cordle's thesis.  To each their own.  

[iacas]

1 minute ago, Divot Tool said:

I'm not debating the fact that the lag isn't thrown away. . it must be inevitably released.  All great ball hitters had lag pressure and understood HOW and WHEN to release it.

Lag is not actively "released." The clubhead comes out of lag and is thrown out because the hands slow down. It's a matter of sequencing, not anyone actively "releasing" anything.

1 minute ago, Divot Tool said:

All I'm saying the difference between the best ball strikers that ever lived and every the average weekend chop as Cordle illustrates is that they reach a straight line condition after impact and the average chop dumps it before impact.  It can not be any more clear. 

Nobody has ever debated that.

What has been debated is:

• That maintaining PP3 into and just past impact (you've talked about how they still have a ton of "lag pressure" AT impact) is what's actually happening, and
• Whether the DST will remain bent when swung "properly" in your eyes (it does not).

1 minute ago, Divot Tool said:

Are we really pushing at PP3, or is that pressure a result of the shaft loading?

The shaft isn't still "loading" at impact. PP3, regardless of how you get it, is dramatically decreasing throughout much of the downswing. This is contrary to your statements about how Brooks Koepka et al have a "ton" of lag pressure at impact, and how it needs to be "maintained" or some such.

That's not what happens.

1 minute ago, Divot Tool said:

The technology that we are blessed with today was created from the need to quantify and thus comprehend why the BEST do what they do.  Force Plates, Bodi-Trak, Trackman, Gears et al don't make you a great ball stiker, they are merely tools.

These tools have helped us understand what's actually happening in the golf swing.

1 minute ago, Divot Tool said:

Actually, no we're not in agreement here.  Great ball strikers don't reach a straight line condition until well after impact.

You're wrong here. Hell, your very first picture of Vijay has it lined up at impact.

1 minute ago, Divot Tool said:

Here's a photo of Vijay Singh that actually captures his impact conditions.  Looks familiar.  

Right hand is barely on the club. Virtually no "lag pressure" here.

1 minute ago, Divot Tool said:

Here's a photo of Couples at impact. No cupping here at impact.

It's cupped. As it has to be because of the left-hand grip being a bit strong. But, clearly, cupped, as the left wrist has been on many, many good ball strikers.

1 minute ago, Divot Tool said:

If one were to look at the photo you posted above where the club is already parallel with the ground well past impact, one might come to the conclusion that he flipped it

I don't think anyone who knows much about golf is going to "come to the conclusion that a major winner flipped it."

1 minute ago, Divot Tool said:

If the left wrist didn't cup post impact, he'd be hooking it off the planet.  Nonetheless, it's not cupped at impact because he's hasn't dumped his lag like the weekend chopper.

Oy.

[Divot Tool]

1 hour ago, Vinsk said:

Again....nobody said he flips. . .

 

It’s an idea for which I have no data, nor physics to support it. These tour pros are not superior ball strikers because of what they do with their right index finger.

Great ball strikers load, lag and understand their release point.  Ball ball strikers throw it out, flip it cast it etc before impact.  So you're either a flipper/caster or you're compressing it with leverage.  You're free to choose which one is more effective for you.  I think the best ball strikers that ever lived would agree with me.

 

Lastly, It's not about their index finger or PP3. It's about 96% of golfers (per Cordle research) casting the club, reaching a straight line condition before impact and the vast majority of golfers retaining lag and reaching full extension after impact. 

 But if you're going to conflate effective ball striking with solely the index finger, that's your prerogative.  

 

[Vinsk]

1 minute ago, Divot Tool said:

Great ball strikers load, lag and understand their release point.  Ball ball strikers throw it out, flip it cast it etc before impact.  So you're either a flipper/caster or you're compressing it with leverage.  You're free to choose which one is more effective for you.  I think the best ball strikers that ever lived would agree with me.

 

Lastly, It's not about their index finger or PP3. It's about 96% of golfers (per Cordle research) casting the club, reaching a straight line condition before impact and the vast majority of golfers retaining lag and reaching full extension after impact. 

 But if you're going to conflate effective ball striking with solely the index finger, that's your prerogative.  

 

We’re not discussing lag. We’re all aware of lag. You’re phrase is ‘lag pressure’ which as you’ve defined doesn’t correlate with physics. And don’t be silly, nobody here is saying good ball strikers flip the club. We’re simply saying you have made statements that don’t correlate with the physics of what’s actually happening. 

7 minutes ago, Divot Tool said:

Great ball strikers load, lag and understand their release point.  Ball ball strikers throw it out, flip it cast it etc before impact.  So you're either a flipper/caster or you're compressing it with leverage.  You're free to choose which one is more effective for you.  I think the best ball strikers that ever lived would agree with me.

 

Lastly, It's not about their index finger or PP3. It's about 96% of golfers (per Cordle research) casting the club, reaching a straight line condition before impact and the vast majority of golfers retaining lag and reaching full extension after impact. 

 But if you're going to conflate effective ball striking with solely the index finger, that's your prerogative.  

 

Let me guess...bad angle? Not even close to being in line huh?

[iacas]

1 hour ago, Divot Tool said:

Great ball strikers load, lag and understand their release point. Ball ball strikers throw it out, flip it cast it etc before impact.

Please show me where anyone has disagreed with any of that.

1 hour ago, Divot Tool said:

So you're either a flipper/caster or you're compressing it with leverage.

I prefer the term "deforming" (deformation, not compression), and I'm with you again right up until the bold words, which given your post history, I read as "with lag pressure supplying that leverage."

1 hour ago, Divot Tool said:

Lastly, It's not about their index finger or PP3. It's about 96% of golfers (per Cordle research) casting the club, reaching a straight line condition before impact and the vast majority of golfers retaining lag and reaching full extension after impact. 

Buddy, you're the one who has made it about "lag pressure" and PP3!

You've gotten no debate from anyone here that the great majority of golfers line it up prematurely. None.

1 hour ago, Divot Tool said:

But if you're going to conflate effective ball striking with solely the index finger, that's your prerogative.

🤦‍♂️