Heavy hit
 

HK wrote-: "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". "

I don't really understand the concept of a "heavy hit" in a swinger's action.

Here is a link to a golfer performing a left arm swing.

http://www.youtube.com/watch?v=uUTk7m5PozQ

This is presumably drag loading at its purest. Does he have a "heavy hit"? What would a swinger need to do in order to have a "heavy hit" if PA#2 releases passively/automatically according to the principle of the endless belt?

Jeff.

Jeff,
In studying the Golfing Machine - it's important that you are precise in your terms- otherwise you can get off course quickly. You've quoted Homer Kelley and then thrown in your own words "heavy hit". It would be better for you and all - that you stay with his terminology and then ask the questions in regards to his writings. I don't mean that as an attack on you- rather a piece of advice that I think may help you- or anyone reading the post/thread. It's just that "heavy hit" brings in a whole additional slant- it really is just a reflection of your question/ your mind's issue - in that - How can the swinger have a heavy feeling if they are not actively driving the shaft? Or How can the swinger have a heavy feeling compared to the hitter? (doesn't)

Therefore, there is no "precise measurement" such as 4 lbs- that equals a heavy "hit". It's relative - heavy and slower is better than quick and fast in order to regain lag IF you are experience "throwaway" via over-acceleration creating a condition of dissipating lag before impact.

If having lag is slow and heavy and losing lag is quick and fast - then whether swinging or hitting- if one is feeling quick, fast and having over-acceleration then one solution is to sense slow and heavy. Certainly, the overall sensation between swinging and hitting will not be the same - the one having an active "direct" drive and the other having an "indirect" passive "drive"- one pushing - one pulling.

And so it goes.... Knowledge is ALWAYS relative, contextual. It isn't created separately, independently in a vacuum.

Finally, somewhat outside of this post- but in the same vain - you see many attacking Homer Kelley's idea of "Hitting", that "Pure hitting" is only 54% powerful, etc. etc. Trying to destroy the concept by measuring every single force, fiber, etc. and determining that only X% is pushing and "therefore there is not such thing as "Pure Hitting"- that Homer Kelley had it wrong." The same people would invalidate every concept in existence - For Example, there is no such thing as a "Pure Table" - because we've measured all of them and they are all different sizes, made from different materials, hold different books and magazines, are in different places, different colors, ............ If that's how you see the world or you'd like to join them - then read up on your leader - Immanual Kant - where you can find all you want to know about "Pure Knowledge"- take some LSD while you're at it - so you can get that "Pure Knowledge" - you wouldn't want your senses to get in the way. Meanwhile, the guy on the street can tell you if he's pushing the car or pulling the car- while the professor might ask you "How do you know that's a car?" "For that matter, how do you even know that you exist?" "Maybe it's just a dream?"

Hey, BamBam! What's your mailing address- I've got a package to send you - call it a power package!

Mike - you make a relevant point about "feeling" slow and deliberate ia an important "feeling" in a swinger who suffers from over-acceleration and clubhead throwaway.

However, I am interested in a specific answer to my question's primary implications. One needs lag at impact to hit the ball solidly. The Iron Byron machine is adjusted (in terms of central arm speed and club release point) so that the clubhead is just behind the peripheral hinge joint at impact (like the one arm golfer). That ensures that the clubshaft has forward shaft lean at impact. For a given clubhead speed at impact and given degree of forward shaft lean at impact, does the quality of lag affect ball flight distance? In other words, does a swinger have the ability to modulate the quality of lag at impact and produce a "heavy hit" (? increased smash factor) that can increase the amount of energy imparted to the ball, and therefore ball flight distance, for a given clubhead speed and given amounf of forward shaft lean at impact?

Jeff.

Jeff, I agree with Mike, "heavy hit" is a phrase not in the book and is laced with the blood of previous arguments... but the correct impact feel is as Homer described...slow and heavy and dragging moppish...if that feels like "heavy hit" ...then that is your feel... Homer said "'heavy' feel" (2-E)

But I think that you want some facts about the "quantity of impact"... Homer suggested that the physics of impact could be maximised if the clubhead did not slow down much through impact interval

IMO, the real questions you seek answers for are:

How does Homer explain the benefits of resisting impact deceleration?
The bit of the book you are interested is in 2-E . I do not know if the science is correct but the idea that if you can minimise the deceleration of the clubhead during impact "zero deceleration is what would give maximum ball speed..."

Can a golfer resist impact deceleration? Homer suggested prestressed clubshaft... yet most high speed swing visions show the shaft releasing before impact...

as I am sure you have read - "Search for the Perfect Swing" said the clubhead acted like a free orbiting object...so anything you feel in the shaft at impact is not actually resisting impact deceleration...it is as though there is no shaft...maybe...

That is where a real and unbiased physics person is required....

He was discussing the "feel" of moving a club head that "feels" heavy. Flippy, handsy, over-acceleration through impact makes the club feel light but maintaining the lag through the strike causes the club to feel heavier.

I find this thread very interesting. As a newbie, I have been thinking of what the guys on TV call a "heavy hit" as having a large amount of pressure on the shaft at impact/separation. My thought was a swinger would be feeling this pressure primarily in PP#4.

Before starting on my learning of TGM, I felt ZERO pressure at impact, and my golf swing had never been worse. Perhaps I am thinking of too many ideas in terms of my newly found "secret", lag pressure?

Kevin

Kevin, I think that a swinger will have lost all pp4 sensation at impact...but they will have sustained pp3 lag sensation to and beyond impact.

I think the bit that Jeff is getting at is if you have a clubhead with right forearm on plane and lag pressure pp3 sustained....do you get more ball speed for a given clubhead speed (ie. higher smash factor).

HK seemed to have thought so - (from my understanding of TGM) - the pre-stressed shaft, lots of anatomical support to the shaft at impact to keep it driving....resisting impact deceleration. Analogy like would you prefer to be hit by a free flying fist at 30 mph...or a fist at 30 mph attached to a heavyweight? Some say the ball only knows energy (1/2 x mass x velocity squared)...so what about the size of the guy... fist -head collision is different to clubface - ball...

The science guys would say that any force you exert on the shaft at impact does not get transmitted to the clubhead/ball...the clubhead is just orbiting and colliding on its own...but it orbits in a better manner if you do as HK said....but maybe not resists impact deceleration for the reason he said it.

I do not know enough about the science to work out what is correct... but lag is a good thing...but maybe for reasons other than HK suggested.

Thanks GolfBullDog, wonderful explanation! Now as I remember in my Alignment Golf DVDs, the left arm is starting on it's "blast off" on the downswing. Is that why we lose our feeling of pressure there? In S&T, they also explain the use of Accumulator #4 as a steady acceleration motion beginning at the top of the downstroke. Same principle?

I appreciate your time!

Kevin

Another link in the chain!
 

How many of you have actually done this? I had read about it...cited it...then one day I did it! I didn't actually drag a wet mop, but I did take several strands (5 X 3 ft.) of chain and attach them together then placed them over the end of the grip down to the head of an old club. You talk about heavy this or heavy that but only when you feel it does it make much sense...for me that is. Hitting a golf ball right after dragging the dry chains was almost surreal! You don't get it until you feel it.

Golfbulldog - you are correctly identifying my question.

You wrote-: "the idea that if you can minimise the deceleration of the clubhead during impact "zero deceleration is what would give maximum ball speed...".

Is that possible? Is it possible to ensure that the clubhead does not decelerate during impact by maintaining a lot of clubhead lag pressure (presumably by increasing right triceps muscle push-tone force during impact)? When PA#2 releases, there is presumably a sense of decreased lag pressure at PP#3. I presume that a good golfer instinctively increases right triceps isometric muscle tone to prevent any decrease in the "feel" of lag pressure at PP#3 (during the PA#2 release process) from happening. Is that true considering how fast PA#2 releases? Is that controllable/trainable?

Jeff.

No one is exempt from Newton's Laws
 

Not possible. It is all about resisting the inevitable.

Jeff, To keep it simple - As you are referring to right triceps muscle push- you'd be limiting your discussion to hitting.

If you lose lag pressure when you release an accumulator- you've got problems!

DIG

I didn't think that it is possible. I was wondering whether people were postulating varying amounts of right arm thrust power for a given amount of right wrist bend at impact (= given amount of forward shaft lean = given amount of clubhead lag) even though swingers do not actively hit.

Jeff.

Ea
 

Couldn't this slight increase in right tricept muscle force also be atributed to extensor action, it is impossible for the right tricept to ever be completly inert as some force must be exterted to creast extensor action to take the slack out of the assembly.

Jeff . . . Homer said that he felt lag pressure so strong that he felt like he could lift himself off the ground . . . BUT he also said that lag pressure is measured out in ounces not pounds. That a pound of lag pressure would be too much to sustain . . . hmmmmmmm . . . . not really sure how to reconcile that.

I'm not sure that in your above post you actually are equating lag pressure with shaft lean . . . . there is a connection there . . . however . . . . . . . . . shaft lean must also be metered out in appropriate amounts for the shot at hand and the club in hand . . . . . nicking the loft with shaft lean on the short irons works . . . . but maybe not such a good concept with the longer less lofted irons . . . see Lee Trevino . . . .

This is one of the reasons you want to be sure that you take your grip at fix . . . . a "leany" fix maybe really good with the short irons . . . but you may need the loft with the longer clubs so back of the lean and swing appropriately.

There is "accumulator lag", "lagging components", a "lagging clubhead" and LAG PRESSURE. You don't have to have ooodles of the first 3 to have the last one. Pressure is . . . well pressure. Swingers generally will feel less pressure generally due to the loading and the pressure point loading on the knuckle and moving back to the fleshy pad (or not moving).

Pull up! Pull up!
 

12P,

Do you think this is where the club manufacturers have done a number on us? I feel as my mechanics get better my ball flight becomes lower. I know how to fix this...at...fix, but I love the crunch that a "leany" shaft provides. Is that why Trevino put a 6 wood in the bag? Too much shaft lean made the butter knifes impractical? It seems as though good mechanics and modern lofts are somewhat at odds.

Within the context Jeff's post- I was thinking any comment to right tricep pushing was used in the context of an acceleration force. Certainly, in the context of your post - regarding extensor action there would be right tricep muscle force attributed to extensor action- separate from any pushing acceleration force.

12PB

You wrote-: "Jeff . . . Homer said that he felt lag pressure so strong that he felt like he could lift himself off the ground . . . BUT he also said that lag pressure is measured out in ounces not pounds. That a pound of lag pressure would be too much to sustain . . . hmmmmmmm . . . . not really sure how to reconcile that."

That's my problem understanding lag pressure and its affect on ball flight distance. Each club needs a different level of forward shaft lean at impact (more for short irons). Therefore, for a given amount of forward clubshaft lean and a given clubhead speed at impact, wouldn't the amount of lag pressure experienced at impact be the same for different swinger-golfers who do not drive load the shaft? How could there be variations in the degree of loss of clubhead forward speed due to impact? How could different golfers have different levels of a "heavy hit" (whatever that means)?

Jeff.

resisting impact...
 

Jeff, the section I quoted from 2-E (6th edition) about zero deceleration was Homer's statement - a theoretical ideal not a practical one... but it does appear that he thought that some resistance to deceleration was possible by maintaining shaft stress through lag pressure.

This may be an area for TGM summit people ?

Perhaps scientifically incorrect but a very real feeling.?? LAG pressure at impact is the way to achieve it...if it is possible to resist deceleration....but then we want lag pressure at impact for other reasons (alignment / stop floipping)....

So stick with lag pressure - let science people worry about impact deceleration - but in the back of your mind accept that HK may have got that that bit incorrect...but he got the big bits right.

Resistance is futile...
 

http://nmgolfscience.tripod.com/img/collisions.gif

That's the pertinent equation shown at that link above. (you'll have to copy/paste it into your browser it seems)

Ma - is the "effective" mass striking the ball (Mb)
e - is the coefficient of restitution
Vo - is clubhead speed before impact
Va - is clubhead speed after impact
Vb - is ball speed after impact

If you drop a ball onto a massive hard surface it will (partially) rebound. The ratio of the height it rebounds to to the height it is dropped from is "e" or COR. COR (coefficient of restitution) accounts for energy lost during deformation.

Normally the club head might weigh .2 kg and the ball 0.046 kg. The governing equation tells us that:

Vb = 0.813 * Vo ( 1 + e )

If you are using a modern high-tech driver then

e = 0.83 and Vb = 1.48 Vo

The question is is there anything a golfer can do to increase the "effective mass" - Ma ? Is there anything a golfer can do to make the .2kg club head look more massive?

---------

Think of a diving board. The diver "jumps" on the "spring board" and it deflects. The diving board is a cantilevered beam which is a kind of spring. The golf club is also like a cantilevered beam. But because of the centripetal loading (which is not insignificant) the golf club is an "axial loaded" cantilevered beam. A beam with axial load is significantly more stiff than an ordinary cantilevered beam. Nevertheless it is still a (relatively flexible) spring.

http://nmgolfscience.tripod.com/img/ballspringch.gif

That link shows a diagram of the situation. If the spring supporting the 0.2 kg club head mass (labeled "beam" in the diagram) were infinitely stiff... then the collisions would be identical to the case where a ball bounces off a hard floor. In that case the governing equation tells us :

Vb = (1 + e ) Vo or Vb = 1.83 Vo

But club shafts being swung by fleshy palms are not infinitely stiff. The and the stiffness of a shaft (spring constant) is set by design parameters at the time of manufacture not what the golfer is or is not doing before, during or after impact.

In Conclusion

The golfer can do nothing to resist CH deceleration. Its set by the ratio of the masses (both club head and ball) and to a much much lesser extent the spring stiffness of the shaft (an axial loaded cantilevered beam).

For all practical purposes Cochran and Stobbs got that one correct.

Homer liked a "stock" amount of lag pressure . .. for consistency reasons I think. Hitters typically feel the load more due to the nature of the loading.

I'm not sure that there's a correlation of shaft lean to lag pressure . . . plus you may feel more pressure with longer clubs simply because they are longer. Bottom line you want to have a lag pressure that you can SUSTAIN and the PROPER amount of shaft lean for the shot you have selected and hopefully programmed at fix.

In reference to the heavy feeling through impact, Tom Tomasello said it was sensed by keeping an awareness of moderately light grip pressure. If your grip pressure was too firm, the clubhead felt lighter. If the pressure was light, the clubhead felt heavier. Another slant on the topic, which may or may not help.

UPP in snowy Ohio

Collisions equation:



Austin was talking about a one-iron he made where he brazed a tungsten rod to the back of the club-face at the sweet spot. By doing that he increased Ma from what's normally about 0.2 kg to something much more. Maybe it was 0.3 kg.... So then assuming he could swing a "heavy" one-iron (say 0.3 kg) just as fast as he could swing a "light" one-iron (0.2 kg) tt (remember he was big and quite a strong athlete)

Vb = Vo (.3/.346)(1 + e) or Vo => 0.86 * 1.83 Vo = 1.58 Vo

1.58/1.48 = 7.2%

The ball would leave the club-face of Mike's modified one-iron having 7.2% more speed (provided he could swing the club just as fast). You see there is the catch. The heavier the club the more inertia it has. The more inertia it has the more force (and torque) is required to accelerate it. Over the years golfers have arrived at the optimal compromise for a given body type... we call that that "swing weight".

Its safe to say few people would be able to make Mike Austin's modified one-iron perform. Perhaps Sean Fister or Jason Zubak could...

Thanks for doing the sums NMG!

You're welcome... I'll do a write up with the equations of motion (showing effect of spring stiffness as a variable on the collision response) eventually. I'm learning a new language (java) to make interactive web applets to simulate these effects as I type.

I have a "new" theory on the "heavy hit" idea.

Could variations in the degree of downplane right shoulder thrust affect the amount of clubhead speed loss during impact due to ball collision, and the amount of energy imparted to the ball for a given clubhead speed and a given amount of forward shaft lean?

Consider a swinger's action. The release sequence is 4:2:3. The club reaches impact due to the passive release of PA#2 which is a CF-induced action. The right hand must keep up to maintain clubhead lag through impact. The right arm straightens passively in the downswing, but there must be enough right triceps muscle contraction to allow the right arm to straighten enough to allow the right hand to keep up with the left hand and maintain a bent right wrist/FLW through impact. However, straightening the right arm may not be enough if the right shoulder socket doesn't move forward enough downplane to support the right arm - so that one doesn't run-out-of-right arm. The more the right shoulder moves downplane, the more bent the right arm can be at impact. I am thinking of Hogan who had a very assertive pivot rotational action that allowed him to drive his hands inside very quickly post-impact, and that is presumably due to an actively driving right shoulder downplane. Could that driving right shoulder add thrust power (drive loading power) to the right hand at impact (passively via the bones of the right arm/forearm/hand) and thereby increase swing power at impact - even if one is a swinger?

Jeff.

more Resistance is futile....
 

I've prepared a page for those who might be interested in reading more about the "heavy hit". Its at:

http://nmgolfscience.tripod.com/heavy_hit.htm

Heavy Hit

Don't think so
 

No... The collision takes place so fast, and the equipment is so flexible, there is nothing a golfer can do to change what is, what will be. On another forum I refer to this fact of life as:

Getting it done before hand .... because once ball and club head meet...

as they say...

That's all she wrote.

Jeff, I think that you got to let this one die... the science guys seem pretty strong on this one...and any way it does not matter. Lag and alignments are better places to spend your time IMO.

NMGolfer , you know Mandrin ?

Golfbulldog

I never felt strongly about this issue. I always thought that ball flight distance was related to clubhead speed, and not to the pressure exerted on the shaft at impact in swingers where PA#2 is released passively. I am a little surprised that it also applies to hitters who drive load the clubshaft. Do you therefore believe that in a hitter's drive loading action, that the only factor is clubhead speed at impact and that push-pressure behind the clubshaft has no additive effect?

nmgolfer

I presume that the clubhead must have a finite amount of weight so that the clubface doesn't deform at impact. Presuming that the clubface is sufficiently rigid, you are presumably stating that additional clubhead weight and/or additional push-pressure thrust exerted by the golfer has no effect on ball flight distance (other than its effect on clubhead speed at impact). Is that correct?

What about the possibility of clubhead acceleration through impact due to drive loading in a hitter's action. In your mathematical model, you are presuming that clubhead speed remains constant for the entire duration of ball-clubface contact in both situations. However, wouldn't increased drive loading (thrust force = push-force) allow the clubhead to continue to accelerate while it remains in contact with the ball for a duration of 1/4000 second? A hitter is not simply applying increased mass behind his drive loading action - he is also thrusting and accelerating the club through the impact zone.

Jeff.

even More Resistance is futile...
 

Jeff, There is nothing the golfer can do during impact that can effect the outcome of the shot. More Here

nm golfer

Thanks for adding more commentary.

I need to think about this issue some more, although you seem to be correct.

Did you make a typo error at the end of your collisions paper?

You wrote -: "Prevent the club from drastically accelerating."

Don't you mean "decelerating"?

Jeff.

Jeff.... Yes... I fixed it now. I need to spell check and edit better. Also I like your approach ... simple documents with out fancy backgrounds etc. In time I'm going to put a bunch of docs on that web site and fix the index.htm page.

nmgolfer

I look forward to your papers. I trust your maths more than Mandrin's. What is your url address for your index page?

Jeff.

Whats the story with Mandrin?

http://nmgolfscience.tripod.com/
 

Its not there yet but it will be :

http://nmgolfscience.tripod.com/

After a hiatus I'm beginning to focus on golf again and hope to get things better organized soon.

Who knows... Irritable bowel syndrome?

:laughing9

Clear Liquids
 

I just love the Absolut Mandrin Vodka; it has a-peal.

Mandrin posts (at least he/she did the last time I was there) on Manzella's forum.