Is Lag from the left shoulder through impact possible?

[BerntR]

I was really intrigued by reading the 1.68 thread, the hand path and the forces at work throughout the down stroke. Thanks for a lot for a sharing some of the findings.

But there was something that really puzzled me. I got the impression that impact lag pressure have been declared non existent. That the club is freewheeling through impact. Because there's no lag in the shaft? Because there's no shear forces imposed and sustained by the golfer on the shaft? No torque on the handle?

But towards the release you can create lag pressure by just pulling from the left shoulder. A plain ol' fashioned shoulder turn through impact will give some of the same as the "parametric acceleration" effort.

The shoulder turn creates a forward alignment from the shoulder, through the hands and to the sweet spot. As long as you turn, the left shoulder will stay in front of the swing center. So you're not just pulling in towards the swing center. You are also pulling forward. You have linear force (per TGM) right there.

Then of course you can have more of the same by pushing from the right. It will tighten the rope. Which means increased axial force from the hands to the sweet spot. Don't need any shear forces to create lag pressure.

Admittedly, the shaft bending that goes on towards impact complicates matters. It makes the club temporarily longer, to some extent like a rubber band that is being stretched. But with the right shaft there should still be some power transmission going on.

I wonder if you guys measured the axial forces in the shaft throughout the swing? If there is any impact lag pressure there, the axial force in the shaft will be bigger than what it takes to simply keep the sweet spot in orbit. I figure this is measurable.

If there isn't any lag pressure there anyway it is tempting to think that you might as well stall the shoulder turn right at impact. I guess some world class golfers are closer to that than others. Others turn hard and fast through impact and beyond as Hogan did.

Perhaps Trackman data for smash factor could shed a light on this too. Is there any correlation between smash factor and the speed of the left shoulder through impact?

 

[Brian Manzella]

ZERO to be gained by any pushing through impact.

ZeeeeeeRow

 

[BerntR]

Thank you Brian for an excellent answer;-)

ZERO to be gained by any pushing through impact.

ZeeeeeeRow

Unfortunately your response had nothing to do with my question. My question was about pulling and not pushing.

From the response it looks like my opening lines in this thread didn't make sense to you at all. But these questions are rooted in physics and mechanical science.

I have been suspecting that pp#3 pressure through impacted have been overrated for quite some time and I applaud that you guys have hammered home that point. But there's more to lag pressure than pushing through impact. There's pulling too. I have reason to believe that lag pressure is created by pulling as well. I may be wrong, but there's no way anyone can know this until it has been investigated thoroughly. And so far no one I'm aware of have asked and answered the right questions.

I applaud your findings, but I think you guys have left out a couple of important issues from your investigations.

 

[Brian Manzella]

What do you think all the force going normal pre/at/&just-post impact is????

PULLING LIKE CRAZY.

Inward.

Toward the golfer.

 

[BerntR]

What do you think all the force going normal pre/at/&just-post impact is????

PULLING LIKE CRAZY.

Inward.

Toward the golfer.

Inward and forward. Forward because of pulling from the left shoulder.

Big diff between just inward and inward + forward.

I'm not questioning the motion, btw. What you guys have come up with there makes a lot of sense.

I'm curious about how and why it works. I am certain that the forward part of the pulling creates lag pressure and I am also open to that this lag pressure increases as a response to the impact shock - and that this happens fast enough to make a difference to the ball compression.

Have you guys checked the speed of sound in a modern graphite or steel shaft? There's plenty of time for the shaft to respond before the ball has left the club face. Not with shear forces, mind you, but with axial forces.

I've also broken the shaft a couple of times right at impact and right above the hosel so I've seen what happens to the ball flight when the club head and the ball is having a private moment at impact.

 

[BerntR]

dbl,

I use the conventional definition of lag pressure to the extent that it is applicable. But perhaps translated to a more generalized understanding. Lag pressure is really a "linear force" component per TGM that is sustained. Homer had his lever systems and lag pressure points 1-4 defined so anyone who thinks about this strictly in TGM terms will look for linear pressure from one of the four pressure points defined in TGM.

But I am looking at the left side - shoulder and arm - with new eyes. I see lag pressure generated from the left shoulder.

Not quite a lag pressure point in TGM sense since HK was a bit trapped in his lever based system, with hinge pins, moving clubhead mass and a (lag pressure) force that worked at right angles somewhere on the lever. All of Homer's lag pressure points work somewhere down either the primary or secondary lever.

In my opinion he got it very wrong with pp#4 because he failed to see how the turning left shoulder leverage the swing. If it worked as per the book, we would all have black bruises on our chest and our upper arms, wouldn't we? From the "tremendous" pp#4 pressure - the only true channel for leveraging the efforts of the pivot rotation. And it wouldn't be any point in pulling from the left shoulder towards impact after the left arm hat separated from pp#4 since the left shoulder didn't have any pressure point to leverage through....

In TGM it is implicit that accumulator #4 has reached its inline condition when the left hand is straight in front of your left shoulder. That is about as wrong as it can be, because that's the alignment that gives the left shoulder max levarage.

You can look at this strictly geometrically and you will see that there is close to a 90 degree angle between your left shoulder girdle and the left arm + club shaft towards impact. That means that the left shoulder is pulling from an angle that is about as far away from the swing center as it can get.

The forward lean runs up the shaft and through the left arm and all the way to the left shoulder so you don't need any shear forces somewhere down on the primary lever to have lag pressure. Good old pulling does the trick.

The angle between the shoulder girdle and the primary lever works in pretty much the same way as the wrist cock did between the primary and secondary lever earlier in the down stroke. Only you don't need a pp#1 equivalent up there to keep the left shoulder in the lead. There is plenty of "extensior action" - structural support- in the shoulder girdle from birth that is far more solid than any extensior action you can come up with. Then you have all the mass of the pivot that has picked up some rotational speed as well. All you need to do is turn your shoulders and assure that the club head doesn't turn past the hand before impact.

I think the lag pressure and the pulling from the left shoulder can be so strong that hands more forward will only weaken the lag pressure at impact because you then introduce slack between the shoulder and the sweet spot. The ideal would have been a fully uncocked left wrist, a very inert grip and the distance between the left shoulder and the sweet spot was max before impact, because then there wouldn't be any buffers left between a strong, heavy rotating shoulder girdle and the sweet spot.

If Homer had been born later he might have gone to college and learned a bit more mechanics than he had at his disposal. The term TORQUE is sadly missing from TGM. With Torque you can create lag pressure without having a lag pressure point somewhere down on the lever assembly. The shoulder motion is basically a torque, leveraged to the golf ball by push-pull from both hands.

The "parametric" acceleration that has been launched recently is really just the same as the torque that I've described above. This is only a new discovery to the extent that the basic physics involved in the golf swing hasn't been properly understood.

The pivot torque has of course a right side too, the pushing part. I am sure a lot can be said about that as well but all in good time.

 

[Brian Manzella]

Luke Donald loses ALL of his right wrist bend from last parallel to his left thigh.

All 55° of it.

ANY LAG PRESSURE WOULD KILL THAT DEAD.

Please comment.

 

[BerntR]

Luke Donald loses ALL of his right wrist bend from last parallel to his left thigh.

All 55° of it.

ANY LAG PRESSURE WOULD KILL THAT DEAD.

Please comment.

Yes. If you pull something that's ahead of you, deceleration is probably one of the better outcomes you can hope for.

I think Homer was onto something important with his definition of rhythm. Unfortunately, part of his definition stated that club and arm travels on the same RPM throughout which isn't true. The shaft lags the arms with approx 90 degrees at the top and approx 0 degrees at imapact and rotates at least 90 degrees more than the arms to the end. Knowing that most of the extra 180 degrees of rotation happens from hip height to hip height it's fair to say that the cpm difference between club and arms are vast from hip height to hip height. A flat left wrist maintained through forearm rotation doesn't change that.

The videos I've seen of Luke lately looks better than they used to, btw. He looks really good here for instance: Luke Donald - YouTube


But why do you ask this question?

 

[Brian Manzella]

These questions were brought up by BerntR about a week ago.

I am giving him OUR FULL ATTENTION.

I will call as many of our scientists as I have to get get the answers.


Bernt, can you simply make three points out of your posts, and I will start calling.


Best I can figure, these are the points you are making.


1. Since the left shoulder is "in front of" the sweetspot, no matter how much you are pulling up on the grip, no matter how much the shaft is bending forward, the sheer sweetspot being "behind" the left shoulder, and the left shoulder is attached to the arm, and the arm is attached to the hand, and the hand is holding the grip—then the left shoulder is moving the club forward just pre-impact and at impact.

2. The forward part of the pulling of the left shoulder creates lag pressure—which is by definition, pressure on the backside of the shaft—and this lag pressure increases as a response to the impact shock—pre-impact—and that this happens fast enough to make a difference to the ball compression.

3. I think Homer Kelley was onto something important with his definition of rhythm & a flat left wrist maintained through forearm rotation doesn't change that.


And, I may be 100% wrong, but here are my answers to those questions based on my 30 years of experience and last few years of research with real scientists.


1. Any "lag pressure" at impact is incidental and has no bearing on the impact collision and the distance the ball travels.

2. Nothing going on just before impact, as a response to the impact shock—pre-impact, has any bearing on the impact collision or distance.

3. I think that any idea of rhythm in the golf swing, as per TGM, is closer to being 100% wrong than 100% correct.


I may be 100% wrong, and Bernt you may be correct.


But, I will find the answers and put them up here.


Please correct me, if I have any of your premises incorrect.

 

[Mike O]

Free Guidance

BM "creates lag pressure—which is by definition, pressure on the backside of the shaft"

Brian, I've seen you posting ideas over and over which have puzzled me or not made any sense to me. Your quote above really isolates the issue, in regards to why I've had this disagreement in my mind. A more proper definition would be "Lag pressure is the result of sensing inertia". It would be improper to isolate it to the back of the shaft (maybe lingering TGM concepts), but since you have and with some of the newer information you're working with - you've essentially said "you don't want lag pressure" at or near impact, given you're definition of lag pressure and the idea of no radial force. Use the appropriate and broader defintion and you'll be headed more in the right direction.

The golf concept lag pressure refers to the sensory awareness of something lagging, which requires:
1) a living entity that can sense i.e. normal human being, and
2) acceleration of something attached to the sensing entity i.e. club, arm, leg i.e. different joints, etc. regardless of whether that's a push or a pull and
finally to use lag pressure as a procedural que you need
3) to be aware of it. (otherwise it's just a scientific notation)

2nd issue
Much like way back when you guys i.e. MJ, Mandarin, and yourself, were analyzing impact and hinging, through to the stuff you're working on today, you keep isolating a section of the movement, such as impact and then make judgements and coming up with conclusions without taking into account the context of what created that section, the overall factors, and how it relates to the player.

Which leads to stuff like this:
1. Any "lag pressure" at impact is incidental and has no bearing on the impact collision and the distance the ball travels.

2. Nothing going on just before impact, as a response to the impact shock—pre-impact, has any bearing on the impact collision or distance.

Which doesn't have alot of merit one way or the other - since as a golfer someone would ask themselves (even if it was true) "How do I use this information?" For number 2 above "should I not worry or not do anything right before impact? If not "what should I do before that?" Hence, that's the problem working with scientists - that you have to overcome - becuase they have the same problem - "isolationism". Get the pieces from them but follow the proper rules for putting the puzzle together - becuase they don't know them.

 

[drewyallop]

"2. Nothing going on just before impact, as a response to the impact shock—pre-impact, has any bearing on the impact collision or distance."


I don't get this. How can something be a response to something that has not happened yet, i.e. impact?

 

[footwedge]

"2. Nothing going on just before impact, as a response to the impact shock—pre-impact, has any bearing on the impact collision or distance."


I don't get this. How can something be a response to something that has not happened yet, i.e. impact?

Ever flinch before getting hit with something?

 

[birly-shirly]

I'll bet Wulsy has.

 

[spktho]

BM "creates lag pressure—which is by definition, pressure on the backside of the shaft"

Much like way back when you guys i.e. MJ, Mandarin, and yourself, were analyzing impact and hinging, through to the stuff you're working on today, you keep isolating a section of the movement, such as impact and then make judgements and coming up with conclusions without taking into account the context of what created that section, the overall factors, and how it relates to the player.

Which leads to stuff like this:
1. Any "lag pressure" at impact is incidental and has no bearing on the impact collision and the distance the ball travels.

2. Nothing going on just before impact, as a response to the impact shock—pre-impact, has any bearing on the impact collision or distance.

Which doesn't have alot of merit one way or the other - since as a golfer someone would ask themselves (even if it was true) "How do I use this information?" For number 2 above "should I not worry or not do anything right before impact? If not "what should I do before that?" Hence, that's the problem working with scientists - that you have to overcome - becuase they have the same problem - "isolationism". Get the pieces from them but follow the proper rules for putting the puzzle together - becuase they don't know them.

I'm not too sure the scientists are losing perspective as to how the parts of the swing relate to the whole. I guess it would all depend on what each individual scientist is most interested in finding out about the golf swing.

It is my understanding on this issue that their studies show any force across the shaft from the hands/pivot occurs somewhere in the transition and in the downswing--the timing is individual and there is more than likely an individual optimum. By the time impact comes, there is a negligible to no force across the shaft from the hands. The force measured near and at impact from the hands is up the shaft or toward the golfer.

Ideally, this is purely evidence from their own measurements and from their models. This is why the 2 things you pointed out as conclusions and judgements aren't viewed that way by scientists. They are measured and are consequences of some action(s) by the golfer. It is not saying a golfer does not try to impart the radial force (pushing or pulling) all the way through impact.

I also think that Bman and his team are definitely finding ways to implement the information they find through their study of the swing in their teaching. The information they leak is just that, information. Brian has said many times it is not instructional material from him. He is implementing the information in his teaching, but has not informed the forum of how he is implementing it.

 

[dbl]

Good stuff, spktho. I am in agreement. The scientists are not necessarily, and even unlikely, to do be doing what Mike accused them (or BM/MJ) of.

As well, Mike, if you have a desire to find out what's bugging you about the analysis or model...let's ask up front...when all the info is laid out who do you think will need to adjust their thinking...the scientists and BM/MJ....OR....you? Right now I'm hearing you say that what they are saying is not matching the throughts or principles you hold. I'm sure when BM/MJ put their full info out a lot of people who previously thought X or Y or x' or Z'' or B3 or J2 aren't going to initially like what is presented. Brian has already indicated the rising attacks and criticism.

 

[drewyallop]

Ever flinch before getting hit with something?

OK now I think I understand. It is the impending impact, no? Your body knows that impact is coming so it does what? FATS? Flinch? What?

 

[footwedge]

OK now I think I understand. Your body knows that impact is coming so it does what? FATS? Flinch? What?

If something does happen how does it square with Zick's assertion that once release starts there is nothing more the golfer can do to affect the physics of the club (I am paraphrasing, could be wrong)

Oh! I was talking about the ball knowing what's coming...lol. I have no idea what someone might do or not do anticipating impact, I wish I knew wtf I was doing, but self 2 won't talk to me the uncommunicating dictator that he is.

 

[footwedge]

I'll bet Wulsy has.

That's funny but probably true.

 

[Mike O]

By the time impact comes, there is a negligible to no radial force on the shaft from the hands. The force measured near and at impact from the hands is up the shaft or toward the golfer.

Not arguing, or commenting except that - make sure you are using the term properly - Radial Force IS up the shaft.

 

[Mike O]

Good stuff, spktho. I am in agreement. The scientists are not necessarily, and even unlikely, to do be doing what Mike accused them (or BM/MJ) of.

As well, Mike, if you have a desire to find out what's bugging you about the analysis or model...let's ask up front...when all the info is laid out who do you think will need to adjust their thinking...the scientists and BM/MJ....OR....you? Right now I'm hearing you say that what they are saying is not matching the throughts or principles you hold. I'm sure when BM/MJ put their full info out a lot of people who previously thought X or Y or x' or Z'' or B3 or J2 aren't going to initially like what is presented. Brian has already indicated the rising attacks and criticism.

You didn't understand my post