Kelvin Miyahira: pro or con

[Tod Johnson]

[color=#282828][quote name='russc' timestamp='1412302991' post='10227515'][/color]
[b]There is no doubt that grip and setup affects the way that a golfer swings. and I think in Jamie's swing hugely affects the way that he swings [/b][color=#282828].[/quote][/color]

[color=#282828]Agreed.[/color]


[color=#282828][quote][/color][b]Jamies very strong right hand grip is a factor in his rolling his arm going back(right arm going below left in the backswing ) .[/b][color=#282828][/quote][/color]

[color=#282828]I wouldn't get hung up on that, since the arms lift straight up with a high right elbow Nicklaus would be proud of.[/color]


[color=#282828][quote][/color][b]The rule of thumb is that the stronger the rotation going down,the stronger that the grip should be(Mr Hogan is the obvious exception)[/b][color=#282828][/quote][/color]

[color=#282828]That sounds like the worst rule of thumb I've ever heard, a recipe for hooking and misery. [/color]

[color=#282828]EDIT: Oops, I misunderstood. I thought you meant arm rotation going down. Any strength grip will do so long as you use the correct combination of left forearm supination, left wrist palmar flexion, right forearm pronation and right wrist extension. I agree, though, that it is easier to manage all those things with a stronger grip, which is why Lucas and all his students use one. Kel is willing to work with weaker grips.[/color]

[Tod Johnson]

[quote][b]His stance is very wide even in comparison with Kelvin's other gold medal winners .Among other things this wide stance is a major factor in his large amount of tilt at setup ,his arm position at setup and his tilt at impact.[/b][/quote]

His stance and setup reflects the shot he is trying to hit. What's the big deal?


[quote][b]A wider stance makes it difficult to rotate the right knee and(hip) inwards. going back. [/b][/quote]

Not in my experience.

[quote][b]His very wide stance facilitates his huge "Snead squat"which is in another league even compared to most other gold medal winners. [/b][/quote]

One of the best in golf.


[quote][b]It makes it impossible to move enough laterally to avoid the "look" of spinning in the lower downswing.[/b][/quote]

First of all, that's rubbish, second, who cares what it "looks" like?

[Tod Johnson]

[quote][b]The problem IMOP in using Jamie as a model is that golfers who try to imitate him without proper instruction just do not have his abilties and often end up with an mish mash of a swing with the right knee moving outside the right heel,the head rotating way too far ,the left heel coming too far off of the ground.[/b][/quote]

Give me a break. Other than talented teens, every student who tries to do anything significant without proper instruction will screw things up. The swing is just too damned complicated.


[quote][b]Much better would be to use another gold medal winner .like Gary Woodland as a model.[/b][/quote]

Ha. Believe me, Woodland's weak grip and flat arm swing require much more strength and body control than Jamie's strong grip and high hands. Just look at 4' 11", 100 pound Sofia. Crushes it past contemporaries twice her size and has no problem hitting the grid.

[media=]http://www.youtube.com/watch?v=GwRB8fSBDAQ[/media]

[eightiron]

Getting into that McGill interview , it seems that he thinks SG theory is bunk


Stu McGill: Exactly. See I wasn’t a political back in those days. I was the guy who wanted to know why was the sixty-two year old lady getting injured lifting boxes at the post office and a twenty-two year old wasn’t. We sort of know why, the tissues were weaker. But was she doing other things that, perhaps, loaded the tissues closer to tolerance.

Then we realized that with this entire spectrum of biological variability, you can’t come up with single numbers. This is politics that lawyers want these numbers. We’re going to get into some controversies that are later in my career.

Getting back to these spinal engine and these theories of Doctor Gracovetsky, he was a brilliant engineer and very persuasive speaker. He came up with his colleague, Harry Farfan at the time, who was a spine surgeon who had theories on how the spine worked. He would say things like, “Well, the muscles of the spine are not strong enough.” Now let’s look at this power lifter picking up 400 Kilos from the floor. There’s no way the spine muscles are large enough. Therefore, there must be mechanisms that we do not understand or are in current models. So he came up with the lumbodorsal fascia theory where the fascia gets stretched behind the muscles and takes some of the load. And increases the mechanical advantage of the extensors and this sort of thing.

But when I went at it with my model, I in those days had something like 96 lips of muscle. Everything that crossed the low back and if you take an MRI slice through the lumbar spine, you will see the lumbar musculature cutting cross-section and you’ll measure its size. What you don’t realize is there are muscles all the way up the back that also contribute to that force. But when they are at the lumbar level through the layer of the skin, they’re just a little tendon so you can’t see the muscle. So the fact that his models were ignoring all of this musculature, the latisimmus dorsi, big lat muscles working through the fascia, I didn’t think it was anatomically accurate. If you just captured the anatomy correctly, you didn’t need these very esoteric explanations about how the back was. In fact, it became quite simplified. Then his ideas on when we walk, we move the hips.

Bret: Stu before we get into this spinal engine let me elaborate on that. I actually embedded a video in my blog two years ago because it was a video of Gracovetsky talking about the first facial congress (link is here: http://www.youtube.com/watch?v=B-SMUA3QfVw&list=PL5DC2627D5F32C664&index=1) and he brought that up, and he’s a wonderful speaker and made a joke and the whole audience erupted in laughter. This just goes to show you just how little people know about biomechanics and spinal biomechanics because you could tell them anything and they will believe it. he said that if you look at what the muscles are capable of doing, it is a very small amount. So the lumbar fascia has to be contributing to stabilizing the back. But correct me if I’m wrong, wasn’t he using a smaller moment arm and also the physiological cross sectional area of ordinary people and not power lifters. Correct?

Stu McGill: I don’t even think he captured ordinary people with enough ability for my satisfaction.

Bret: They were elderly cadavers or something.

Stu McGill: I can’t recall exactly where the data came from but again, if you look at the whole spine and capture it, the statement that the muscles are not strong enough is patently wrong.

Bret: You’ve talked about how the thoracic extensors are great stabilizers of the lumbar spine because of their longer moment arms.

Stu McGill: If we get into a study or a conversation on stability, do you wanna spend three or four minutes on that?

Bret: No. Let’s get into that later. So essentially, a lot of this stuff he was talking about at the time. One-by-one you would kind of pick it off. Just talk about the spinal engine real quick. I remember reading that and it just doesn’t make sense. Like you said, it’s very esoteric and elusive. I will tell you that people in our industry are drawn to this. He talked about how if you take a metal rod and you bend it and then twisted and side bend it, it will create rotational torque. That’s what drives gait. What are the problems with that?

Stu McGill: Well the problem is that it’s true for a rod made of fiberglass or graphite or something like that. So let’s replicate the motions that he’s showing in his graphite rod in a real person. What you have to do is walk while swinging your hips, rolling each hip over. Well when you measure people there are some people who have totally the opposite pattern in their hips. In other words, their spinal engine is in reverse. Yet, they’re still able to walk forward. I remember being at a spine meeting one time and Gunnar Andersson, who is a very well known spine surgeon and scientist out of Chicago. He stood up and said, Yes, but this patient right over here. They’ve had a fusion from L1 down to the sacrum. Their spine is stuck in neutral and cannot move. Does that mean they can’t walk?” The fact that the room erupted in laughter the other way. The point is that you have big leg muscles for a reason and that’s how you walk.

Bret: The hips are the engine in most situations, huh?

Stu McGill: Thank you. I thought you might appreciate that.

[AnotherTodJohnson]

Dap,

 

You wrote-: "So far in this bout,TJ has come out swinging and throwing as many punches as he can muster hoping that more blows can score more points and overwhelm the opposition into confusion.

 

ATJ has his gloves up absorbing the blows and perhaps playing rope a dope and not really on the offensive......yet."

 

It is very easy for me to counter Jeffy's blows (which are mainly ad hominem insults) by simply igoring the insults. I no longer have any psychological need to counter his personal insults by generating uncivilized ad hominem insults, and I will simply concentrate my effort on providing an alternative opinion to Jeffys regarding topics related to golf swing biomechanics/mechanics.

 

Here is an example of an alternative opinion relating to the topic of the spine engine.

 

In post #762 Jeffy posted a u-tube video of Jamie Sadlowski hitting a 331 yard drive off his knees and then he rhetorically asked-: "Here is Jamie hitting it 331 off his knees. How much do you think the spine engine contributes relative to the hips and legs in that swing?"

 

I don't think that Jeffy was really seeking an answer (or an alternative opinion) and he is seemingly implying that the spine engine mechanisim is primarily responsible for producing the swing power that allows JS to hit a 331 yard drive without any contribution from significant pelvic motion (because his potential pelvic motion is severely limited in that kneeling position). However, that Jeffy-opinion doesn't make sense to me because the primary purpose of the spine engine is to help rotate the pelvis counterclockwise (= amplify the counterclockwise rotary motion of the pelvis which is being primarily rotated by the pelvic girdle muscles), but if the pelvis cannot significantly rotate (because it is impeded by being so close to the ground rather than free-floating on two legs) then it should not be possible for the spine engine to be contributing to the generation of swing power. The true reality is that JS generates his swing power in the kneeling position by a very active rotation of his mid-upper torso secondary to an active contraction of the core muscles of his mid-upper torso. The rotation of his upper torso, and therefore his two shoulder sockets, provides the pivot-induced swing power that allows him to swing his arms at a very fast velocity into impact. Clubhead speed at impact is directly correlated with left arm speed (speed of release of PA#4 in TGM terms), and his left arm speed between P6 and impact is primarily affected by the speed of rotation of his mid-upper torso - when he is in the kneeling position. There is simply no reason to posit the scientifically-unsupported concept of a "spine engine".

 

Jeffy also posted a comparison image of JS and Tiger Woods at P6 in post #763

 

 

 

Jeffy stated with respect to this image-: "Pretty similar, except I'd say Jamie has more right side lateral bend, so his hips and shoulders are more open than Tiger's. He's probably gonna generate 140mph of CHS v. Tiger's 125."

 

He has made two claims that I think are irrational and without logical merit. First of all, he claims that JS's pelvis is more open than TW's pelvis at P6 because he has more right lateral bend. I think that his claim has zero merit because I don't believe that right lateral bend can contribute to an increase in pelvic rotational velocity - because I don't believe in the spine engine theory. I suspect that JS's pelvis is more open than TW's pelvis at P6 because JS is generating more pelvic rotational velocity between P4 and P6 due to a more efficient contraction of his 6 lateral pelvic rotatror muscles that are the causative agents that are primarily responsible for generating pelvic rotational speed in the early-mid downswing. Secondly, he is implying that the difference in CH speeds (140mph for JS versus 125mp for TW) is due to this small difference in pelvic rotational velocity at P6. I totally disagree! I can think of much more significant differences between their two swing actions that are much more likely to be responsible for their CH speed differences - i) JS has a much greater degree of upper torso (shoulder rotation) in his backswing generating a much greater degree of static X-factor and also a much greater potential range of upper torso counterclockwise rotary motion that can be utilized during his downswing action; ii) JS has his left arm much further back at the P4 position and his left arm is positioned higher above his right mid-clavicle, which combined with his ultra-flexible left wrist, allows him to get his clubshaft to go well beyond the horizontal position with a much greater degree of lag; iii) JS maintains a much greater of lag for much longer in his early-mid downswing. I also suspect that JS can pivot much faster than TW because he is much lighter in weight, and because he is ultra-flexible and because he uses a reverse-weight shift pattern between P6 and P7. Another less significant factor is that JS uses a very strong left hand grip, which means that he doesn't have to rotate his left forearm counterclockwise in the late downswing (which represents the release of PA#3 in TGM terms) in order to square his clubface by impact. By contrast, TW used a weak-neutral left hand grip in 2000, and that means that he had to marginally slow his left arm motion in the very late downswing to allow for the complete release of PA#3, which is a necessary requirement if if he wants to have a square clubface at impact.

 

Finally, I also noted that Jeffy made the following comment in his discussion of the JS-TW comparison-: "Second fire happens from P5 to P7, with extension of both hips and knees, and contraction of both hip adductors, pulling the thighs together". Jeffy believes that this 2nd pelvic firing phenomenon can increase swing power. However, I don't agree - because I have never read any biomechanically-rational explanation that can explain how extending the legs (and thereby lifting the body in a vertical direction) can increase CH speed at impact other than through the mechanism of parametric acceleration (which is not seen to any significant degree in either JS's or TW's swings if you carefully examine their hand arc paths between P6 and P7).

 

ATJ.

[Mitchell]

So a party can have been banned from site for inappropriate behavior, yet a discussion perpetuated by and about same individual and his behaviors and opinions on another site is allowed to continue incessantly here? Disappointing.

[eightiron]

^^^ Tod will counter that claim above by saying that with the hips and spine engine second fire being unrestrained Jamie gets another 100 yards lmao

[eightiron]

Interesting stuff by SG using evolution as a platform for the spine engine theory


In his interview, Gracovetsky stated-: "The presumed starting point (as it is only a hypothesis) is that primitive fish, 450 million years ago, moved in the same way as modern fish, i.e. by a lateral inflection movement of the spine. Fish which subsequently ventured onto dry land were faced with several problems,the first being to move by planting their fins into the mud by means of an alternating movement. This axial rotation movement combined with the lateral flexion movement resulted in the movements of flexion and extension. Thus, the simple need to move over small pebbles led our fish to invent flexion and extension movements. This same flexion-extension movement subsequently allowed galloping and the development of the lower limbs, as the para-axial muscles gradually moved outside of the abdominal cavity to become hamstring muscles, in order to increase the brute power available for locomotion."


Hmmm more like they got on dry land and flapped around for a minute , but I have located the missing link . A piranha evolving into a human

[Tod Johnson]

I also want to mention in kelvins article that he uses woods and it looks like his hip moves left before the right said bend. That is apparent in your sequences also. JS already way compressed - tiger wasn't. Think that was at p5/6 ish. Where I saw the biggest difference - if the Right side lateral bend is supposed to send the left hip open. I don't see it in that dTL Tiger sequence at all.

 

 

Take a look at this GIF. Tiger has a huge amount of lateral bend in the 1997 sequence and his left hip is open the most in that one Over time, he reduces lateral bend, until, by 2013, he starts looking like he did when he was two years old.

 

[Tod Johnson]

[quote name='eightiron' timestamp='1412318044' post='10228367']
^^^ [b]Tod will counter that claim above by saying that with the hips and spine engine second fire being unrestrained Jamie gets another 100 yards lmao[/b]
[/quote]

Another 75 yards, at least: he easily hits it 400 on his feet. Kinda obvious. Lucas gets another 60 or more. LMAO

[eightiron]

I also want to mention in kelvins article that he uses woods and it looks like his hip moves left before the right said bend. That is apparent in your sequences also. JS already way compressed - tiger wasn't. Think that was at p5/6 ish. Where I saw the biggest difference - if the Right side lateral bend is supposed to send the left hip open. I don't see it in that dTL Tiger sequence at all.

 

 

Take a look at this GIF. Tiger has a huge amount of lateral bend in the 1997 sequence and his left hip is open the most in that one Over time, he reduces lateral bend, until, by 2013, he starts looking like he did when he was two years old.

 

 

Wouldn't it be better to use the back view to observe when right side lateral bend starts in the downswing? Jeff Mann does some nice sequences of sadlowski and woodland showing the lateral bend occurs mid downswing. Although it might be hard to spot how much lead side lateral bend has to be reversed out of . Don't we have machines that measure this stuff now

[AnotherTodJohnson]

Eightiron,

 

You wrote-: "Tod will counter that claim above by saying that with the hips and spine engine second fire being unrestrained Jamie gets another 100 yards."

 

It is obvious that JS will be able to hit the ball further (75-100 yards further) if his pelvis can move in a more unrestrained fashion. However, that doesn't mean that the swing power contribution from an unrestrained pelvic motion involves the spine engine. The 6 pelvic lateral rotator muscles are perfectly capable of rotating the pelvis counterclockwise at great speed between P4 and P6, and there is no need to believe that a golfer needs any swing power contribution from the rotating upper torso (either via the spine engine idea or via the coupling mechanism's passive forces which I previously described). The rotary motion of the pelvis only contributes to swing power in the early-mid downswing, and generating a faster pelvic rotation between P6 and P7 doesn't contribute to swing power. Jeffy has previoulsy tried to prove that JamieS was accelerating his pelvis (from a rotational perspective) all the way into impact, but he was eventually proven wrong and he now concedes that pelvic rotation reaches its peak rotational velocity well before impact. Rory McIlroy is one of the longest hitters on the PGA tour - despite his small size and despite the stalling of his rotary pelvic motion between P6 and P8. However, I believe that he generates his considerable swing power secondary to an optimised kinetic sequence where the pelvis rotates superfast between P4 and P6 while the upper torso (shoulders) continue to rotate superfast throughout the remainder of the downswing and followthrough. In fact, his shoulders rotate so fast after impact that it causes a temporary reversal of pelvic motion as can be seen in this TPI image.

 

 

Note that his pelvic rotational velocity (red curve) peaks well before impact, and that it then slows down and even temporarily reverses direction shortly after impact - due to the rapid shoulder rotation that is happening at that time.

 

Jeff.

[AnotherTodJohnson]

Tod posted this image of Tiger Woods showing a variable degree of right lateral bend during his playing career - with less right lateral bend in 2013.

 

 

Presuming that the images are accurately reflective of his standard driver swing (and not only his iron swings), then what point is he trying to make. Is he trying to infer that Tiger is hitting the ball less far now because he has less right lateral bend and therefore less spine engine involvement? Then, he would need to demonstrate that Tiger's rotary pelvic motion is consequentially more sluggish secondary to a lesser contribution from the spine engine (because that's how the spine engine is supposed to contribute to swing power by supplementing the pelvic rotary motion power that is primarily produced by the pelvic girdle muscles). I suspect that Tiger has not slowed down his pelvic rotary speed between P4 and P6, although I much prefer his 1997/2000 swing action compared to his 2013 swing action. In his 2013 swing action, his pelvis stalls between P6 and P7 due to his propensity to use the Sean Foley (S&T-derived) technique of pelvic motion while in 1997/2000 his pelvic motion was much more rotary (like Jamie Sadlowski). I very much dislike Tiger's 2013 swing action where he bobs down in his early downswing and then "jumps-up" in his later (pre-impact) downswing action. He was not doing that in 1997/2000 where his pelvic motion was very rotary and where he maintained his spinal bend alignment angle through impact.

 

Although I don't believe that right lateral bend contributes to swing power (via the spine engine theory) I am very much in favor of a golfer acquiring right lateral bend during the mid-late downswing. It has two major advantages.

 

Advantage number 1:

 

It allows a golfer to get his clubshaft on a shallower plane (eg. hand plane or elbow plane rather than the TSP) during the club's travel through the general impact zone between P6 and impact.

 

Here is a comparative photo of 5 golfers through impact - Alvaros Quiros, JB Holmes, Phil Mickelson, Hunter Mahan and Keegan Bradley.

 

 

Phil Mickelson has virtually no right lateral bend and his clubshaft is on the steeper TSP, while Hunter Mahan and Keegan Bradley have much more right lateral bend and they can therefore get their clubshaft on a shallower plane while simultaneously getting their right forearm more horizontally-aligned.

 

Advantage number 2:

 

Having a lot of right lateral bend is a great advantage if a golfer wants to use a no-roll DH-hand release action - rather than a less stable full-roll DH-hand release action - through impact. I discussed the difference between these two different types of hand release action in great detail in my impact chapter - http://perfectgolfsw....net/impact.htm

 

Ben Hogan is the prototypical example of a golfer who used a no-roll DH-hand release action as can be seen in this next sequence of capture images from this you-tube video.

 

[media=]

[/media]

 

Capture images

 

 

Lee Trevino also routinely used a no-roll DH-hand release action through impact as can be seen in this next series of images.

 

 

See images 9 and 10 - note that LT is using a no-roll DH-hand release action between P7 and P7.5 , and note that he has a lot of right lateral bend that allows him to get his right shoulder well downplane through impact so that he doesn't run-out-of-right arm (note that he still has a bent right wrist at P7.5).

 

Here is another example of a golfer using a no-roll DH-hand release action through impact.

 

Charley Hoffman

 

 

 

ATJ.

[ej002]

You cannot put hogan in that hold off drive / block release nonsense category.

Worked for Lee aiming 20* left. No one else really.

[eightiron]

[quote name='ej002' timestamp='1412354151' post='10230087']
You cannot put hogan in that hold off drive / block release nonsense category.

Worked for Lee aiming 20* left. No one else really.
[/quote]

It never ceases to amaze me how we get the no roll baloney . I will bet the house if Mann could ever find elbow plane with all the 3 accum and no rolled it , he wouldn't hit the ball

[pappaf2]

I also want to mention in kelvins article that he uses woods and it looks like his hip moves left before the right said bend. That is apparent in your sequences also. JS already way compressed - tiger wasn't. Think that was at p5/6 ish. Where I saw the biggest difference - if the Right side lateral bend is supposed to send the left hip open. I don't see it in that dTL Tiger sequence at all.

 

 

Take a look at this GIF. Tiger has a huge amount of lateral bend in the 1997 sequence and his left hip is open the most in that one Over time, he reduces lateral bend, until, by 2013, he starts looking like he did when he was two years old.

 

 

It's been mentioned before but I don't think the picture titled 2013 is from 2013. It looks much more like tiger in the Haney days with the high handed follow through. Plus he isn't wearing the nike free shoes, they are an older model shoe.

[spider]

I'm so lost and it has nothing to do with spine engine theory blah blah blah. So TJ is Jeffy and ATJ is Jeff Mann. right? So many 3rd person references gets me lost. Waiting for Mike Finney or Shields to pop up here prefereably from some bush taking pictures.

[Mcaesq]

I also want to mention in kelvins article that he uses woods and it looks like his hip moves left before the right said bend. That is apparent in your sequences also. JS already way compressed - tiger wasn't. Think that was at p5/6 ish. Where I saw the biggest difference - if the Right side lateral bend is supposed to send the left hip open. I don't see it in that dTL Tiger sequence at all.

 

 

Take a look at this GIF. Tiger has a huge amount of lateral bend in the 1997 sequence and his left hip is open the most in that one Over time, he reduces lateral bend, until, by 2013, he starts looking like he did when he was two years old.

 

 

It's been mentioned before but I don't think the picture titled 2013 is from 2013. It looks much more like tiger in the Haney days with the high handed follow through. Plus he isn't wearing the nike free shoes, they are an older model shoe.

Personally, I prefer the 1978 swing.

[RichieHunt]

[quote name='spider' timestamp='1412361744' post='10230737']
I'm so lost and it has nothing to do with spine engine theory blah blah blah. So TJ is Jeffy and ATJ is Jeff Mann. right? So many 3rd person references gets me lost. Waiting for Mike Finney or Shields to pop up here prefereably from some bush taking pictures.
[/quote]

As long as they post under the handle Jon Tohdson, that would work with me.




RH

[AnotherTodJohnson]

ej002 wrote-: "[i]You cannot put hogan in that hold off drive / block release nonsense category[/i]."

He seemingly has no idea what's my definition of a no-roll DH-hand release action because it is definitely not a hold-off or a block release action.

Hogan is clearly using a no-roll DH-hand release action in the capture image swing sequence that I posted. Hogan is using it in conjunction with a CP-arm release action while Lee Trevino used it in combination with a CF-arm release action.

eightiron wrote-: "[i]It never ceases to amaze me how we get the no roll baloney . I will bet the house if Mann could ever find elbow plane with all the 3 accum and no rolled it , he wouldn't hit the ball[/i]".

I strongly suspect that he also has no idea what I mean by a no-roll DH-hand release action because the no-roll only refers to the P7 to P7.2 time period and it doesn't refer to the pre-impact downswing time period.

Jeff.

[Tod Johnson]

[quote name='eightiron' timestamp='1412313770' post='10228259']
Getting into that McGill interview , it seems that he thinks SG theory is bunk


Stu McGill: Exactly. See I wasn’t a political back in those days. I was the guy who wanted to know why was the sixty-two year old lady getting injured lifting boxes at the post office and a twenty-two year old wasn’t. We sort of know why, the tissues were weaker. But was she doing other things that, perhaps, loaded the tissues closer to tolerance.

Then we realized that with this entire spectrum of biological variability, you can’t come up with single numbers. This is politics that lawyers want these numbers. We’re going to get into some controversies that are later in my career.

Getting back to these spinal engine and these theories of Doctor Gracovetsky, he was a brilliant engineer and very persuasive speaker. He came up with his colleague, Harry Farfan at the time, who was a spine surgeon who had theories on how the spine worked. He would say things like, “Well, the muscles of the spine are not strong enough.” Now let’s look at this power lifter picking up 400 Kilos from the floor. There’s no way the spine muscles are large enough. Therefore, there must be mechanisms that we do not understand or are in current models. So he came up with the lumbodorsal fascia theory where the fascia gets stretched behind the muscles and takes some of the load. And increases the mechanical advantage of the extensors and this sort of thing.

[b]But when I went at it with my model,[/b] I in those days had something like 96 lips of muscle. Everything that crossed the low back and if you take an MRI slice through the lumbar spine, you will see the lumbar musculature cutting cross-section and you’ll measure its size. What you don’t realize is there are muscles all the way up the back that also contribute to that force. But when they are at the lumbar level through the layer of the skin, they’re just a little tendon so you can’t see the muscle. So the fact that his models were ignoring all of this musculature, the latisimmus dorsi, big lat muscles working through the fascia, I didn’t think it was anatomically accurate. If you just captured the anatomy correctly, you didn’t need these very esoteric explanations about how the back was. In fact, it became quite simplified. Then his ideas on when we walk, we move the hips.[/quote]

Two sides to every story. First thing you should know is they were debating conclusions from computer models they had built, not a study of actual subjects. Gracovetsky notes in his book that one can design a model of a complex system to give you any answer you want. Second, Gracovetsky noted that the conclusions from McGill's model were never verified with experimental data. Third, McGill concedes in his book that "further study" remains to be done in this area.

[Tod Johnson]

Eightiron,

 

However, I believe that he generates his considerable swing power secondary to an optimised kinetic sequence where the pelvis rotates superfast between P4 and P6 while the upper torso (shoulders) continue to rotate superfast throughout the remainder of the downswing and followthrough. In fact, his shoulders rotate so fast after impact that it causes a temporary reversal of pelvic motion as can be seen in this TPI image.

 

 

Note that his pelvic rotational velocity (red curve) peaks well before impact, and that it then slows down and even temporarily reverses direction shortly after impact - due to the rapid shoulder rotation that is happening at that time.

 

Jeff.

 

 

Interesting concept.

 

Let's step back into reality. For the thorax to be accelerating counter-clockwise post-impact, a torque must be applied in the counter-clockwise direction. For the pelvis to accelerate clockwise, a torque must be applied in the clockwise direction. What is the mechanism by which applying a counter-clockwise torque to the thorax creates a clockwise torque that is simultaneously applied to the pelvis? Also, what is the source of the torque that accelerates the thorax?

 

 

 

Jeff

[Tod Johnson]

[quote name='eightiron' timestamp='1412354711' post='10230129']
[quote name='ej002' timestamp='1412354151' post='10230087']
You cannot put hogan in that hold off drive / block release nonsense category.

Worked for Lee aiming 20* left. No one else really.
[/quote]

[b]It never ceases to amaze me how we get the no roll baloney [/b]. I will bet the house if Mann could ever find elbow plane with all the 3 accum and no rolled it , he wouldn't hit the ball
[/quote]

[quote name='AnotherTodJohnson' timestamp='1412379286' post='10231905']

[b]I strongly suspect that he also has no idea what I mean by a no-roll DH-hand release action because the no-roll only refers to the P7 to P7.2 time period[/b] and it doesn't refer to the pre-impact downswing time period.
[/quote]

Well, the thing about Dr. Mann is he picks and chooses the facts he wants to believe. He has been shown TPI data wrist angle graphs for many tour level players, as well as Sadlowski, and he knows that none have a period of "no roll" between P7 to P7.2. It's physically impossible. But he could not care less.



Jeff

[AnotherTodJohnson]

Jeffy wrote-: "[i]Let's step back into reality. For the thorax to be accelerating counter-clockwise post-impact, a torque must be applied in the counter-clockwise direction. For the pelvis to accelerate clockwise, a torque must be applied in the clockwise direction. What is the mechanism by which applying a counter-clockwise torque to the thorax creates a clockwise torque that is simultaneously applied to the pelvis? Also, what is the source of the torque that accelerates the thorax?[/i]"

Those are two reasonable questions.

First of all, view this video produced by Greg Rose showing Rory's pelvic reversal phenomenon.

[url="https://www.youtube.com/watch?v=UeF9-U5r3So"]https://www.youtube....h?v=UeF9-U5r3So[/url]

Greg Rose claims that the pelvic reversal is due to the contraction of his abdominal oblique muscles. I have little sympathy for that explantion.

I believe that it is due the superfast thorax acceleration that is happening at that same time. I prefer Phil Cheetham's explanation - see the next you-tube video.

[url="https://www.youtube.com/watch?v=UXL63p893GQ"]https://www.youtube....h?v=UXL63p893G[/url]

Note that his pelvis moves in the opposite direction when he accelerates his thorax in a counterclockwise direction. That pelvic reversal phenomenon can only happen in that scenario because he is sitting in a swivel-chair and his feet are not grounded - and it is predicted by Newton's 3rd law (for every action, there is an equal and opposite reaction). Normally, there is too much impedance to see a golfer manifest the pelvic reversal when the feet are grounded, but I presume that Rory has so much rotary mobility/laxity in his lower thoracic spine area that Newton's 3rd law phenomenon can become visibly manifest.

I cannot explain why Rory's upper torso accelerates in that 3-D graph. I suspect that it is not due to an increased contraction of the core muscles that are rotating his upper torso (shoulders) counterclockwise, but rather due to the fact that the impedance-to-counterclockwise rotation suddenly decreases - possibly due to some intrinsic mobility-property of his lower thoracic spine area that allows for a sudden temporal disjunction between the rotary motion of the upper spine relative to the lower spine.

Jeff.

p.s. The you-tube videos are not visible. I clicked on the "link" button when I linked to the you-tube video. Should I be clicking on some other button to make them visible in the post?

I

[AnotherTodJohnson]

Jeffy wrote-: "Well, the thing about Dr. Mann is he picks and chooses the facts he wants to believe. He has been shown TPI data wrist angle graphs for many tour level players, as well as Sadlowski, and he knows that none have a period of "no roll" between P7 to P7.2. It's physically impossible. But he could not care less."

 

I have had this debate with Jeffy in the past. He prefers to believe in the legitimacy of TPI's 3-D graphs taken at 200 measurements/second while I prefer to believe in the measurements obtained by a Phantom camera video system taken at 5,000 - 10,000 frames/second.

 

Here is John Oda's hand motion through the immediate impact zone taken with Kelvin's Phantom camera at 8,200 frames/second.

 

 

Addendum added later:

 

I have just produced a new capture sequence of Kelli Oride's hand motion through the immediate impact zone - taken with Kelvin's Phantom camera.

 

Here is Kelvin's you-tube video

 

 

Here is the capture sequence.

 

 

Here are the measured angles (using Photoshop)

 

 

 

ATJ.

[eightiron]

[quote name='AnotherTodJohnson' timestamp='1412379286' post='10231905']
ej002 wrote-: "[i]You cannot put hogan in that hold off drive / block release nonsense category[/i]."

He seemingly has no idea what's my definition of a no-roll DH-hand release action because it is definitely not a hold-off or a block release action.

Hogan is clearly using a no-roll DH-hand release action in the capture image swing sequence that I posted. Hogan is using it in conjunction with a CP-arm release action while Lee Trevino used it in combination with a CF-arm release action.

eightiron wrote-: "[i]It never ceases to amaze me how we get the no roll baloney . I will bet the house if Mann could ever find elbow plane with all the 3 accum and no rolled it , he wouldn't hit the ball[/i]".

I strongly suspect that he also has no idea what I mean by a no-roll DH-hand release action because the no-roll only refers to the P7 to P7.2 time period and it doesn't refer to the pre-impact downswing time period.

Jeff.
[/quote]

How on earth can you tell if there is no roll between p7 and p7.2 and what's exactly holding . How is hogan a cp arm release action ? Where did you get that definition from?

[Tod Johnson]

Jeffy wrote-: "Well, the thing about Dr. Mann is he picks and chooses the facts he wants to believe. He has been shown TPI data wrist angle graphs for many tour level players, as well as Sadlowski, and he knows that none have a period of "no roll" between P7 to P7.2. It's physically impossible. But he could not care less."

 

I have had this debate with Jeffy in the past. He prefers to believe in the legitimacy of TPI's 3-D graphs taken at 200 measurements/second while I prefer to believe in the measurements obtained by a Phantom camera video system taken at 5,000 - 10,000 frames/second.

 

Here is John Oda's hand motion through the immediate impact zone taken with Kelvin's Phantom camera at 8,200 frames/second.

 

 

 

Jeff.

 

 

OK, that is the raw data. To determine the wrist movements, you need to perform a tracking analysis. What elements in the video are you tracking, what software are you using to do the tracking, and where are the results of the tracking analysis? What filtering did you use? Could you please plot for us the data you collected?

 

 

 

Jeff

[Tod Johnson]

[quote name='AnotherTodJohnson' timestamp='1412393962' post='10232985']
[b]I cannot explain why Rory's upper torso accelerates in that 3-D graph. [/b][/quote]

Then why are you voicing an opinion on this topic? If you haven't researched this topic in sufficient detail to answer the most basic questions, you have no business authoritatively opining on it. But you couldn't care less.

[quote][b]I suspect that it is not due to an increased contraction of the core muscles that are rotating his upper torso (shoulders) counterclockwise, but rather due to the fact that the impedance-to-counterclockwise rotation suddenly decreases - possibly due to some intrinsic mobility-property of his lower thoracic spine area that allows disjunction between the rotary motion of the upper spine relative to the lower spine.[/b]
[/quote]


Very interesting. What would the generally accepted laws of coupled motion of the spine suggest?

[Tod Johnson]

[quote name='eightiron' timestamp='1412313770' post='10228259']
Bret: No. Let’s get into that later. So essentially, a lot of this stuff he was talking about at the time. One-by-one you would kind of pick it off. Just talk about the spinal engine real quick. I remember reading that and it just doesn’t make sense. Like you said, it’s very esoteric and elusive. I will tell you that people in our industry are drawn to this. He talked about how if you take a metal rod and you bend it and then twisted and side bend it, it will create rotational torque. That’s what drives gait. What are the problems with that?

Stu McGill: Well the problem is that it’s true for a rod made of fiberglass or graphite or something like that. [b]So let’s replicate the motions that he’s showing in his graphite rod in a real person. What you have to do is walk while swinging your hips, rolling each hip over. Well when you measure people there are some people who have totally the opposite pattern in their hips. In other words, their spinal engine is in reverse. Yet, they’re still able to walk forward.[/b][/quote]

This is a blatant straw man. The spinal engine theory does not say such a person can't walk forward. In fact, in his book, Gracovetsky describes the circumstances when a person's spine engine would be in "reverse". Of course, McGill did not describe the gait of such persons. I doubt it would be considered normal.


[quote][b]I remember being at a spine meeting one time and Gunnar Andersson, who is a very well known spine surgeon and scientist out of Chicago. He stood up and said, Yes, but this patient right over here. They’ve had a fusion from L1 down to the sacrum. Their spine is stuck in neutral and cannot move. Does that mean they can’t walk?”[/b] The fact that the room erupted in laughter the other way. The point is that you have big leg muscles for a reason and that’s how you walk.[/quote]

I think this is the low point in the interview and makes McGill look like a low-rent ****** bag. Gracovetsky never said such a person cannot walk. He said such a person would likely have an impaired gait and be susceptible to injury to the adjacent vertebrae. McGill discloses none of this, nor does he disclose whether or not the patient had a normal gait. I highly doubt that he did.



Jeff

[AnotherTodJohnson]

Jeffy wrote-: "[i]Then why are you voicing an opinion on this topic? If you haven't researched this topic in sufficient detail to answer the most basic questions, you have no business authoritatively opining on it. But you couldn't care less[/i]."

It is well known that we are both not golf researchers (scientists) with access to sophisticated scientific techniques. I am also not opining authoritatively, but merely expressing a personal opinion (personal interpretation of 3-D data presented by Greg Rose).

Here is Jeffy opining about Jamie Sadlowski's pelvic rotational velocity during the downswing - [url="http://jeffygolf.com/showthread.php?518-Jamie-Sadlowski-s-hip-rotation-into-impact"]http://jeffygolf.com/showthread.php?518-Jamie-Sadlowski-s-hip-rotation-into-impact[/url]

If you read the 4-page thread, you will soon discover that he is voicing an opinion without having the expertise to be authoritatively analysing the evidence. He later admitted that he was wrong.

What amazing hypocrisy!

Jeff.