Grips And Tilt
 

Zach is definitely 10-2-D. Haven't studied Scott, but...

Check out his extreme 'back' Head position and Axis Tilt here. Look at where his Left Shoulder is in relation to the Ball (not to mention the center of his Stance. There's no doubt he's getting ready to launch one on the Upstroke here!

Offset
 

This may help.
http://www.wishongolf.com/etechrepor...ndex.html#art2

This is no loading. These are illustrations of exceptional hand eye coordination. They will both loose distance because of clubhead impact deceleration (not that they need anymore). Soft Impact. And, with the shaft bending backward, accuracy too. Just serves to demonstrate how talent can be a compensation.

Folks - I swear I am not trying to shake your faith with this forward bending thing, but it is an artifact of the physics. I personally don't see how it materially changes the model that TGM proposes.

Just for the sake of completeness, I will add some references here because people may think I'm making this up.

1) Cochran & Stobbs, "The search for the perfect swing", 1968.
See Figure 32:5 Caption "How bending the shaft forward, as it always is just before impact, closes the face of the club....."

2)Jorgensen, "The Physics of Golf", 1994
See Fig 12.1, also last paragraph of Chapter 12 - "...I think the flexing of the shaft forward as the clubhead comes into the ball is a general characteristic of the golf swing. Photographs made with the use of a focal plane shutter must be ignored in this context. There are few photographs in golf literature made with stroboscopic light sources, but of those I've examined, all of them show clubs flexed in this manner."

3) Horwood (Technical Director Apollo Golf Shafts), "Flexes, Bend Points and Torques", Golf The Scientific Way, 1995 pg 103-108
See Figure 1 "Shaft Bending in Typical Swing" and accompanying text- "Although over half of the 2 second time interval covered by the trace in Figure 1 is taken up by the back swing, it can be seen that the shaft goes from being bent backwards (by about 3 inches) to being bent forwards (by about 2 1/2 inches) in the instant before impact with the ball."

4) Butler & Winfield (True Temper Sports), "What Shaft is Best for You?", Golf The Scientific Way, 1995 pg 113-115
See Figure 1 for deflection curves of a shaft. Accompanying text- "During the load up time, the shaft first loads or deflects anywhere from 2 to 7 inches for a driver. The shaft then unloads and kicks forward at impact."

5) Wishon, "The Search for the Perfect Golf Club", 2005
See Chapter 4 under Three Myths-
"Myth number Two-The second myth is that the clubhead sometimes(usually? often? always?) will "lag behind" just before impact with the ball. .....The release of the wrist-cock also applies something called centrifugal force to the club. That centrifugal force combined with the arms slowing down and the club speeding up causes the shaft to begin to bend forward. And because the arms DO slow down when the wrist-cock is released, the shaft HAS to bend forward before hitting the ball."

Yes I see it too, now that you've pointed it out. Thanks, it's clearer now. Wow, I wonder if trying to launch on the upstroke has lead to the body alignments?

He prolly setup with his head back...I'd guess.

I repeat.......

Excellent post. I can appreciate the amount of work you have researched. However these authors are merely stating observation, not science. They fail to explain why, or state anything other than conjecture.

There is one more Author to consider.

See 6-C-0 #2. There is a reason for that parachute.
6-C-2-A. If the Pressure Point pressure that produced the initial Clubshaft flex is maintained it will maintain the flex also.

The authors I mentioned used high speed video, stroboscopic photographs, and strain gauge measurements to support their reasoning. I'm not sure that HK had those available to him, and, if not, made a perfectly reasonable assumption based on the facts he had at the time. If he did, I'm sure many would be interested in that data.

I'm sure that all of the tools used in "Search for the perfect swing" were available to Homer.

The authors you quote explain their observations. I don't disagree with what they observed. However they fail to explain what causes the shaft to bend backwards. Additionally, they don't conclude what effect this has on impact. Third, they don't advocate this procedure. They have only observed it. In other words, they imply much, prove nothing. Please do me the favor of observing one more photo. Visit the section on this site named "Champions at Impact" and review Lee Trevino at impact. Then, in your own words, if you would kindly do so, explain your observations to me.

So Lee actually played the ball outside of his left foot with an iron? The picture is fuzzy, but to me this looks like a sand shot because part of his foot and the clubhead have been obscured and I would say he's already entered the sand. Great example of a flat left wrist with a 10-2-D.

BTW, some of the authors do discuss the lag situation during the swing - they are all good reads if you can get your hands on them.

I was wondering if you are bold enough to admit that the shaft flex has the Clubhead trailing the shaft?

Yes, it sure does - after impact with a ball, sand or ground.

Do you disagree with the following statement?

6-C-2-A. If the Pressure Point pressure that produced the initial Clubshaft flex is maintained it will maintain the flex also.

Wallop of Centrifugal Force
 

I'm not saying I have the proof regarding shaft flex, or if certain things can be done or not- and certainly there are alot of factors- throwaway etc. that would influence a forward bending shaft. But the above photos of these clubshafts do not necessarily have a forward bending shaft at this point in the swing- if both of these golfers are swingers- which I believe they are- and you have the natural clubshaft "bowing up" that a swinger's shaft has, then when you view that "bowing up" i.e. that upside down "C" from the side as in these photos- then it will appear that the clubshaft is bending forward when it is not. So with so little "bending forward" - and the angle of these photo's - I would think that, that bending forward could be completely attributed to the "bowing up" of the clubshaft- which is the result of the sweetspot lining up with the line of pull/center of gravity application.

I'm sure it probably feels like this happens. All I know is that people who have spent a good deal of scientific study of the dynamic behavior of a shaft indicate that the shaft bends in a certain way during the golf swing and the bend is not constant from the start of the downswing to impact. This happens to be different than the way HK describes it in TGM and that does not cause me any pain but may for others. I have learned a lot from visiting the TGM forums and videos and reading the book and I was a low single-digit to start with. It's amazing how much I didn't know (and still don't) about performing a golf swing. Always room for more learning.....

Strong Single Action Grip
 

Even in a strong single action grip- the back of the left hand does not face in the same horizontal direction as the clubface does.

I guess then, that the 7Th edition may explain this. Then the existing 6-C-2-A section is no longer completely applicable to a swinger.

I'll buy new clubs with extra flexible shafts to get that added "Kick" the shaft will supply as I stop moving my hands to allow the shaft to take over through impact. Hmm? Or I can change to a Hitting stroke pattern.

Ok, you don't agree.

I would have thought so too, and if only a good shaft fitting were that simple, but I probably should have added:

Wishon, "The Search for the Perfect Golf Club", 2005
Chapter 4 Myths-
Myth #3 - "The third myth to bury is that the forward flexing of the shaft just before impact (which some people mistakenly call "buggy-whipping" or "kicking") increases the speed of the clubhead"......

I started this thread by saying I'm much more up on clubfitting than TGM (trying to change that) and that is probably evident in my posts, but I think there's opportunity for incorporating concepts from both to increase one's ability to teach and/or learn to play this game.

Growth
 

Absolutely!-- There's always room for growth and improvement in anything- that's what it is all about.:clap:

Models (Human and Mathematical)
 

One thing to keep in mind specifically with Jorgensen and very likely with the others is the model swing on which their analysis is based. Jorgensen found footage of a particular PGA tour professional (unnamed) and used various images to create a mathematical model. He tweaked his model until it matched up well with that single subject. He may also have commented that his model matched reasonably well to other photographs. At this point he played parametric games with his model to see how the various parameters affected swing speed and other swing features.

What is not known with Jorgensen's human test subject, or possibly with the others as well, is whether the golfer was following the impact principles of TGM or not. Just because someone plays professionally or is a top amateur does not mean they swing in the most optimal fashion in the book. Nothing definitive, therefore, can be said about shaft flex before, during, or after impact unless we have a test subject who unquestionably is retaining maximum on plane lag pressure at impact with flat left wrist and bent right wrist.

BTW, I know the above sounds like some mad lady on a soapbox lecturing the crowd. It is not meant to be that way. I tend to get preachy unintentionally. This thread discussion has been very fun and one I have wanted to start for a long time. You just beat me to it! I think the video footage Yoda referred to will be definitive (one way or another). I also agree that whatever the outcome, the FLW & BRW hands leading clubhead at impact with maximum lag pressure golf stroke will always produce the most ball compression and speed. This is too much fun!!!!

Steph, Thank you for your insight. As a club maker yourself, you've dealt with these issues before and will probably again.

Hmm? Is it possible that someone can do research, get published, and still be wrong? If one then many. Certainly the equipment makers (not the ball makers) with all of their technology have not advanced a players improvement in recent years quite as much as their investment and profits. I don't know that they actually have any interest in improving swing mechanics. I'm sure that they recognize the shortcoming of most teaching professionals and the general population of golfers to make permanent swing mechanic improvements and thus have adopted game improvement equipment to compensate. Certainly they didn't invest million and millions of dollars so that just a few Tour Pro's can make a few more bucks. And certainly, with millions in profits at stake, they aren't going to wait for teaching professionals and the general public to get the job done any time soon. If they can make a shaft, so that anyone can pick up a club and play respectable golf, they certainly would. And maybe that's not as far away as one might think. I think all that is holding them back is the PGA's Club Spec guidelines and the R&A. Until the general golfing public improves their mechanics, and teachers learn the real cause and effects of golf mechanics then game improvement technology will be their crutch, and maybe their savior. Everyone wants to build the ultimate golf club. Besides, historically, equipment makers have sucessfully redefined the game. Four wedges, Metal Drivers, Cavity back irons, graphite shafts. And Golf Course designers seem to be keeping up too. In fact, the only segment that's falling behind is the GOLFER.

Homer Kelley was, and still is, ahead of his time. Something that I have observed in browsing through golf books this evening is that many players exhibit the prestressed clubshaft at impact with shorter clubs and less with longer clubs. This may be due to longer shafts or possibly the difficulty of getting the Pivot to Transport the Power Package fully into the Release area in order to maintain the Prestressed Shaft.

Even Annikan Skywalkers recent thread with pictures of his swinging and hitting Stroke Patterns demonstrate a Prestressed Clubshaft before impact with his Swinging Pattern even more than his Hitting Pattern, though Yoda's comments may lead you to believe the opposite is more likely to be true. The Young man that Annikan illustrates further into the thread exhibits the same tendency. Could these videos be an optical illusion? The mistake would be to abstract these two swings and say that all of his swings work this way. I think that they always want a prestressed shaft but that kind of precision isn't always going to happen in every swing.

Also the mistake would be to take any stop action photo of your sources and conclude that all swings for all golfers demonstrate a similar trait. The majority of the pros can be wrong at the same time. But with time they improve. The Pro's have made some impressive improvements during the past 50 years, and I'm sure that improvements will continue far long after the research you quote fades into obscurity.

THE SECRET

6-C-2-B. ANGULAR ACCELERATION The Clubhead “overtaking” speed is governed by the Law of Conservation of Angular Momentum whereby the increased Mass resulting from any extension of the Swing Radius decelerates the Hands and unless they are supported by Power Package Thrust (6-B-1) or Throw Out Action (2-K), can result in great loss of Clubhead speed. Rely on Clubhead Lag to meter out the necessary support for the Primary Lever Assembly. Strictly speaking, any increase in the product of Mass times Velocity is Acceleration whether or not the speed has changed. But the formula for Kinetic Energy gives Velocity the Greater value. And, actually, the acceptable tolerance in the Ball-to-Clubhead weight ratio is quite small.

6-C-2-C. IMPACT CUSHION The prestressed Clubshaft will resist the added weight of the ball during Impact, instead of cushioning the Impact with an unstressed Clubshaft. See 2-M-1

Clubhead Lag Pressure normally remains constant regardless of the Velocity it has produced. And both #1 and #3 Pressure Points are the product of Accumulator #1.

6-C-2-D. LAG LOSS The very small degree of Clubhead Lag permitted by Clubshaft Flex, makes this procedure especially susceptible to Clubhead Throwaway. And the stiffer the Clubshaft the less margin.

Over-Acceleration is the menace that stalks all Lag and Drag. Here it allows the Hands to reach maximum speed before reaching impact and so dissipates the Lag. So, the length of the Stroke and the amount of Thrust should be adjusted and balanced to produce a “High Thrust-Low Speed” Impact-“heavy” rather than “quick.” Daintiness is dangerous.

Steph - I agree this was fun. I knew it might be a tough crowd, but a honest debate can be a learning experience for everyone. Daryl mentioned some images from Anikan, and I'll have to check those out. It's a miracle sometimes to find some images where contact hasn't already been made. I did find one thread with a sequence of Tiger though caught right before impact that I thought was interesting:

http://www.lynnblakegolf.com/forum/s...ead.php?t=2476

It's probably my crooked straightedge but the clubhead looks bowed forward to me.:) Now to get ready for an early morning round tomorrow.....

I'm sure you have Tigers book. On page 138 the swing sequence shows it Bending the proper way, before contact. I'm sure you can invent a way to dismiss this one too. Interesting how you fail to mention photos that don't support your personal views.

I think that I can move closer to a conclusion on the issue of Prestressed Clubshafts.

Images of golfers using shorter irons exhibit the Prestressed bend through impact that HK wrote about. Most of the pictures of longer shafted clubs did not.

One answer might be that shorter clubs have a greater downward force so that when a clubshaft is initially bent, it may be easier to maintain that bend through impact.

The two photos illustrated in this thread illustrate a reverse bend in the Clubshafts prior to impact but the players appear to be trying to hit up on the ball.

I will keep looking for pictures of a golfer, with a graphite shaft driver who hits down on the ball consistent with TGM theory.

Astute Observation
 

Very astute observation, Mike. If the camera is not perpendicular to the swing plane, in-plane bending cannot always be accurately seen by just observing displacement of the shaft and head in the image. Your explanation in this instance seems the most plausable.

Don't have it - can you post? If it actually is before impact - then we have some conflicting data, but at least we have data.

Mike O - I missed this post from you earlier. What do you mean by "bowing up"? I think you basically reiterated the explanation given by the physics guys for the reason for the forward bend - the fact that the head sweetspot (center of gravity) lines up with the center of gravity of the shaft. Since the sweetspot is actually behind the face and shaft, there is a forward and downward bend (is this what you mean by bowing up?) of the shaft so the head CofG can line up with the shaft axis. For a driver (extreme case) the CofG is usually around 30mm behind the face.

Center of Gravity
 

Actually, bowing up of the shaft was a reference to a vertical frame of reference- that is the Sweetspot is out on the clubhead somewhere- not at the end of the shaft- so the shaft has to bend up or I think Maltby or someone referred to it as clubhead droop. If you have that going on and are looking at it from an angle as in those photo's above-then that alone would look as if the clubhead was ahead of the grip- or bowing forward when really it was just bowing up.

Of course, you bring up a good point- that if the center of gravity of the clubhead is behind the shaft- due to the construction of the club - then that would create a situation for the Swinger who is using centrifugal force- where by during the swing/release -the shaft would be bowing forward.

In that regard, again the Hitter and Swinger are going to have different shaft motions- due to their acceleration methods- and that's why you have the Pre-stressed shaft for the Hitter and the Wallop of Centrifugal force.

For the swinger using centrifugal force (bowing up- to the degree the sweetspot is out away from the end of the shaft i.e. the longer your clubhead the more the shaft will have to bow up or the more the clubhead must droop down)for the Swinger. Likewise, the wider the clubhead/face the more the center of gravity is moved back in relation to the shaft and the more the shaft would have to bend foreward to line the center of gravity up with the #3 pressure point.

Here is the important distinction to make- for the swinger using a driver where the center of gravity of the clubhead is behind the shaft alignment based on the construction of the club. During release centrifugal force will want to line the #3 pressure point or grip end of the clubshaft with the center of gravity of the clubhead i.e. the longitudindal center of gravity of the club itself- thereby creating a situation where the shaft would bow forward. But that wouldn't mean that you don't have a lagging clubhead- if you're pulling/pulling/pulling and creating centrifugal force, you would have clubhead lag- in fact based on the construction of the club- if the shaft was straight and not bowed forward- that would be a situation where you did not have lag if you were Swinging the club!

P.S. pulling/pulling/pulling is more a mechanical description and not a procedural description- because I just invision someone trying to pull/pull/pull to make their movement- so don't go out and do that.

Mike O - Ok, yes I think we're talking about the same thing - and you're right, clubmakers call it droop. I know nobody here gets Golf Digest, but the latest has a good picture of Camilo Villegas on the cover at impact from up the line that shows this. Put a straightedge on the handle and see how much the tip of the shaft has bent downward.

Also, your point on camera angle is well taken. However, I would say that if you could get an image with the head say 6 inches or so before impact the droop would be pretty much invisible (because it's directly perpendicular to the camera angle) to a camera viewing face-on and you'd be seeing the forward or backward bending predominantly. That's why the deflection curves generated by strain gauges that indicate the kind of shaft behavior I described are somewhat more convincing to me. Still, the images I have seen with that just by chance have clubhead very near the impact point have not shown a lagging clubhead - but you never know.:)

Anyways, I think I've kind of beat this subject to death, but while I'm somewhat clear on the difference your referring to with swinging and hitting (longitudinal vs radial), I don't think I understand why the centrifugal (centripetal) force of the clubhead on the shaft would be much different between the two. I'm probably missing the point here but from my college physics days, the centrifugal force would be equal to the clubhead mass times the clubhead speed squared all divided by the radius of the circular motion of the clubhead (at high clubhead speeds it turns out to be quite a large force). None of these factors would seem to be dependent on swinging or hitting given the same clubhead speed(maybe radius slightly?). Maybe TGM is using the term centrifugal force differently than the literal scientific meaning. I'll have to go look at the book again.

BTW, I'm not sure I've been very clear on this, but I wasn't suggesting that there was never clubhead lag in the swing - there certainly is and it is lagging for most of the downswing until the point the clubhead reaches a speed where the centrifugal force overwhelmes any pushing or pulling acceleration on the shaft and drives toward the center of gravity alignment we discussed. Maybe you're saying the same thing in your last paragraph before the PS? Good discussion.

This is an excellent summary and very important to understand for proper clubHEAD control.

Deeper and Deeper
 

[quote=jmessner]Mike O - Ok, yes I think we're talking about the same thing - and you're right, clubmakers call it droop. I know nobody here gets Golf Digest, but the latest has a good picture of Camilo Villegas on the cover at impact from up the line that shows this. Put a straightedge on the handle and see how much the tip of the shaft has bent downward.

Also, your point on camera angle is well taken. However, I would say that if you could get an image with the head say 6 inches or so before impact the droop would be pretty much invisible (because it's directly perpendicular to the camera angle) to a camera viewing face-on and you'd be seeing the forward or backward bending predominantly.
We're in agreement here- exactly my point- thanks for seeing it.

That's why the deflection curves generated by strain gauges that indicate the kind of shaft behavior I described are somewhat more convincing to me. Still, the images I have seen with that just by chance have clubhead very near the impact point have not shown a lagging clubhead - but you never know.:)
See my last comment in this section- I think it applies to your comment here.

Anyways, I think I've kind of beat this subject to death, but while I'm somewhat clear on the difference your referring to with swinging and hitting (longitudinal vs radial), I don't think I understand why the centrifugal (centripetal) force of the clubhead on the shaft would be much different between the two. I'm probably missing the point here but from my college physics days, the centrifugal force would be equal to the clubhead mass times the clubhead speed squared all divided by the radius of the circular motion of the clubhead (at high clubhead speeds it turns out to be quite a large force). None of these factors would seem to be dependent on swinging or hitting given the same clubhead speed(maybe radius slightly?). Maybe TGM is using the term centrifugal force differently than the literal scientific meaning. I'll have to go look at the book again. Good points- would love for you to post the formula with an example- only if you have the time and interest- Hey, there's other things in life to do! As far as your understanding of the clubshaft differences between hitting and swinging- I'm thinking that you aren't quite seeing the difference in regards to TGM- Let's cover it a little later in this thread when I have time.

BTW, I'm not sure I've been very clear on this, but I wasn't suggesting that there was never clubhead lag in the swing - there certainly is and it is lagging for most of the downswing until the point the clubhead reaches a speed where the centrifugal force overwhelmes any pushing or pulling acceleration on the shaft and drives toward the center of gravity alignment we discussed. Maybe you're saying the same thing in your last paragraph before the PS? Good discussion.

I was justing that it might be possible that if the sweet spot was far enough back from the shaft- that you might have a condition where the shaft would curve forward- but the sweetspot would be at or behind that line of pull or longitudinal center of gravity- thereby having lag looked at in relation to the sweetspot but appearing to have throwaway if looking at the clubshaft. That's making a big assumption that the center of gravity that was back of the shaft- would move in line with the shaft by moving forward - and not just close the clubface to get in line with the shaft- as Homer notes on page 82.[/QUOTE]

Notice my comments above, but I'm with you we've beat this horse enough that I've A) lost some interest and B) reached my limit of any significant understanding of the subject matter.

Damn Leo....where you'd get the "Old School" look...Man your your swing looks great!!!!:laughing9

Mike 0 - Just to tie off our discussion because I agree it has run its course - here's the formula and example:

Centripetal Force example
F=m(v^2)/r
m=mass of clubhead (200g for a typical driver)
v=velocity of clubhead (let's assume 100 mph @ impact)
r=radius of curvature of clubhead motion (shaft length is a good approximation, but it could be slightly longer, let's try 45")
Anyway, then F=79 pounds force for this impact condition. The force is considerably less at other points in the swing.

There's a table with similar calcs here plus more discussion on shaft bending.

The second paragraph I quoted I think you have it right. Yes the shaft could bend forward and the sweetspot still not be even with the shaft. In fact, according to some, having the CofG inline with the shaft is the maximum condition that can occur but is not always fully achieved. There is some twisting going on too but I have to assume that it's not the biggest effect - otherwise we'd all be hooking our large headed drivers off the planet and most people tend to have more trouble getting the larger heads around.

thanks
 

thanks- some very good points!

It seems as though the stiffer the shaft the less forward bend the shaft would have at impact with Swinging. If this is the case why wouldn't the Swinger always use the stiffest shaft possible to allow the Hinge Action control the club face more accurately?:question:

As already suggested, I'm no TGM expert on the differences between swinging and hitting but I can give you my view on shaft flex. In general, it takes a faster swingspeed to bend a stiffer shaft a given amount, and shaft bending significantly contributes to the feel of the shaft. So if the golfer can't really bend a shaft it feels harsh, like a pipe, and it might be harder to "feel" the head through your hands during the swing. For some golfers, the feel is important and if the feel isn't just right it throws them off. It also might be harder to square up the face somewhat with less bending and you'll also likely get a lower launch angle. The general rule of thumb is that you'll get a little more control with a stiffer shaft (assuming the golfer swings the same which is a big question if the feel is poor) but better trajectory (maybe distance too) and more solid feel with a more flexible shaft. It is recommended to always go with the more flexible shaft if there is any question.

Hopefully, some experts will weigh in on the application to swingers...

Good subject for a new thread
 

Shaft stiffness should be the subject of a new thread. One thread one subject. I'll start.