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Post by imperfectgolfer on Aug 4, 2014 16:13:48 GMT -5
Jeffy addressed my last post as follows in post #30 of his Jeffy-forum thread on "Jeff Mann". I posted the following statement in my previous post-: " On page 115, he describes the 6 lateral rotator muscles that are used to rotate the pelvis externally from a position of internal rotation (eg. baseball player performing a hitting or pitching action) - piriformis, gemellus superior. gemullus inferior, obturator externus, obturator internus and quadrator femoris". Jeffy replied as follows-: " That sentence is nonsensical because the pelvis does not rotate internally or externally: only the femur in the hip joint rotates internally or externally." Jeffy is partly correct because the left pelvis really undergoes the process of "left transverse pelvic rotation" (which is the counterclockwise rotation of the lead pelvis in a right-handed golfer) while the left femur is being externally rotated and abducted during the transitional time period between P4 and P4.5 (as shown in Bubba Watson's animated gif). However, what causes the biomechanical process of "left transverse pelvic rotation"? Jeffy doesn't deal with this issue. I believe that it occurs automatically/naturally due to activation of the six left lateral rotator muscles that not only rotate the left femoral head within the left hip joint - in a biomechanical scenario where the left leg is relatively unweighted and where the left hemipelvis is relatively free-floating. The counterclockwise rotation of the left femur causes the left knee to move outwards (targetwards) and it also causes the left hip joint (left femoral head/left acetabular socket) to be driven backwards (away from the ball-target line) and also away from the target in a counterclockwise rotary manner - because there is little impedance to the counterclockwise rotation of the left hip joint/left pelvis (left buttocks) in the early downswing when the left hemipelvis is free-floating and the left leg is relatively unweighted. As the left leg progressively straightens in the later downswing, and the left leg/foot become increasingly pressure-weighted, then those 6 lateral rotator muscles do not have the muscle power to continue to unilaterally rotate the left femur, and therefore the left hip joint, counterclockwise. However, that's when the powerful gluteus maximus muscle comes into play and it can cause the left hip joint (and left femur) to continue to rotate counterclockwise, and this rotary pelvic motion is synergistically assisted by "rotary torque forces" that are generated by the downplane motion of the right shoulder and right upper torso. Golfers (like Bubba Watson and Jamie Sadlowski) who manifest the "reverse group" pattern of COP-measurements (where the COP-measurement under the lead foot reverses in magnitude between P5.5 and P7 thereby decreasing the "pressure-weighting" of the lead foot) can potentially generate more pelvic rotation than "front foot" golfers during the later downswing - given the same magnitude of pelvic rotary force - and it can partly explain why golfers like Bubba Watson/Jamie Sadlowski have a more open pelvis at impact. Jeffy also wrote-: " For starters, for the pelvis to rotate around the left hip joint during external rotation would require the left femur to be immobilized.". I think that Jeffy's claim is totally wrongheaded. I think that is very wrongheaded to think of the counterclockwise rotation of the left pelvis (Hogan's left hip clearing action move - where the left pelvis is pulled back to the tush line and where the left buttocks rotates counterclockwise) as being due to rotation of the left pelvis around an immobilised left femur. In fact, I think that the left femur has to be very mobile so that the left femoral head (and left acetabular socket) can more easily move in a counterclockwise manner that drives the lead buttocks to rotate in a counterclockwise manner. One can clearly see that biomechanical phenomenon happening in Bubba Watson's early downswing. Note how extremely mobile BW's lead femur is during the P4 to P4.5 time period - while the lead femur is being externally rotated by the lead pelvic lateral rotator muscles and while the lead femur is being abducted by the lead hip abductor muscles. BW's lead pelvis rotates clockwise secondary to a translatory-rotary movement of the lead femoral head/lead acetabular socket and that requires a very mobile (and not an immobile) femur. Finally, Jeffy wrote-: " What does external rotation and abduction of the left femur have to do with transverse rotation of the pelvis? Mann is acting like a schizophrenic, creating his own world lacking reason or logic.I am not surprised that Jeffy doesn't get it - considering that he believes that the spine engine is needed to produce transverse rotation of the pelvis during the P4 to P4.5 time period (which is actually the same rotary motion as thinking of the "lead pelvis being externally rotated") even though there is no significant amount of right lateral bend present between P4 and P4.5)! Jeff.
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Post by imperfectgolfer on Aug 4, 2014 17:28:50 GMT -5
Grant is obviously miffed when I deleted all his recent posts to this thread and when I finally banned him from this forum - see this thread that he started in the Jeffy forum-: jeffygolf.com/showthread.php?1214-Jeff-Mann-hides-the-evidence-whenever-he-is-caught-red-handedGrant wrote-: " First off, We all know that only people who are bias and have an agenda that does not include the possibility of considering ideas contrary to their own, are the same people that delete posts and ban forum members that dissent. Throughout time, cults, dictators, oppressive governments, corrupt religious institutions have used the tactics that involved attempts to silence opposition and control the information flow. Can we think of one instance where these tactics have been used by someone who wasn't either corrupt, or wrong? Just look at North Korea." Grant wrongly thinks that I deleted his posts because I cannot tolerate a contrary point-of-view regarding topics related to golf swing biomechanics/mechanics. He is delusional! I banned him because he repeatedly (despite many previous warnings) accused me of being deceitful (= not "being honest" = being the antonym of honest). I warned him repeatedly in the past that he could label my personal opinions as being wrongheaded, or misrepresentational, or frankly idiotic - but that I would not tolerate him calling me a blatant liar ( = being blatantly "not honest"). Grant also wrote-: " For all the things jeff says about jeffy... Jeff doesn't delete posts and rarely bans members You can find all sorts of dissenting posts on this forum, still standing". Wow!!!! Talk about being delusional! Grant wasn't around when Jeffy banned me, and many other forum members, from his forum - because he would not accept the "evidentiary quality" of our posts. Grant also made this outrageously wrongheaded allegation that I was lying when he wrote-: " even blatantly changing words like "Should" and "must." Obviously this is important as "Should" is a recommendation meaning essentially "I think that this is the best way, but there may be another." "Must" is a word that means "if you don't do it this way it cannot be done." The two terms "should" and "must" may have a different meaning for Grant, but I personally use those two terms interchangeably/equally without implying a different intent. Grant also wrote-: " Not only that.... and this is unbelievable... but he will do so with one swing, from one angle, with 6 frames, by trying to see what is happening beneath their shirt!!! Haha! Hardly science. Jeff, kelvin has done mutliple research sessions with phantoms, and people removing their shirts, live in 3d from multiple angles with multiple frames. Have you? ... If you haven't, then not only might you be wrong.... but YOU DONT EVEN HAVE THE NECESSARY TOOLS TO MAKE A DETERMINATION OF RIGHT OR WRONG, compared to kelvin. You using a pen and pad, while Kelvin has a calculator." This is a bizarre argument! He doesn't like my analysis of the "degree of rotation/lateral bend of the thoracic spine" as seen from a back viewing perspective, and he thinks that KM is much more precise. Do you think that KM is being precise in delineating the actual position/bend of the spine in this Jamie Sadlowski image? Grant also wrote-: " But all that aside... we go back and find out that Jeff argues against kel's supposed theory that "RIGHT side lateral bend MUST be occurring in transition." Now that may sound like what kel said. But its not. What kel said and what kel believes is that "Lateral bending should occur in transition." Should occur. Important word, especially when coupled with the additional knowledge, THAT JEFF MANN IS AWARE OF, Kel has applauded players like Carl Patterson and acknowledged they don't lateral bend until later in the swing. As if that is not enough, Jeff Mann changes "Should" to "must" and argues against kel as though he said that there must be right side bend in transition. But Clearly that is not the case. Lateral bend must start in transition. A player has left lateral bend at the top, so they begin to stretch in the opposite direction. Their spine must go neutral before it goes to right side bend. So if Jeff mann shows that a player actually has right side bend a frame after transiton, he actually proves kel's theory for him. Why? Because at the top of the swing the player had left side bend. So naturally, in between.... the spine had bent from left to neutral.... and then right. Again, Jeff omits that information." The bold-highlighted statement shows the illogicality/irrationality of Grant's argument. The "fact" that the spine is moving (transitioning) from left lateral bend at P4 to right lateral bend at P5 (or P5.5 or P6) doesn't mean that KM's spine engine theory is "correct" - because the legitimacy of the spine engine theory is dependent on i) the "fact" that the degree of right lateral bend must obviously be of a finite magnitude (eg. probably >30 degrees) to cause a sufficient amount of side-compression of the ipsilateral interfacet joints on the concave side of the lateral bend curve and ii) the compressed interfacet joints must also be capable of interlocking (which is not biomechanically possible when the concave curve only involves the lower thoracic vertebra and not the lumbar vertebra). Here again is an image of the thoracic vertebral interfacet joint articular processes - which are flat like "roof shingles" and therefore incapable of interlocking. There is no "evidence" to support KM's spine engine theory as being the primary motor that powers the pelvic rotary motion during the downswing. Grant is free to present any "evidence" (in that Jeffy-forum thread) that he believes legitimizes a "belief" in the spine engine theory. Jeff.
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Post by imperfectgolfer on Aug 5, 2014 0:19:06 GMT -5
Consider yet again this animated gif of Bubba Watson's early downswing between P4 and P4.5. If you observe the first 2 frames of the animated gif very carefully, then you will note that the first downswing motion involves external rotation of the lead femur combined with lead femur abduction that moves the lead knee targetwards. I believe that those motions are directly due to activation of the lead hip abductor muscle and the 6 lead hip lateral rotator muscles. Note that the lead hip joint rotates clockwise during this same time period - even though there is ZERO motion of the upper torso and lead shoulder socket . That means that a rotary motion of the upper torso doesn't contribute to the clockwise rotation of the pelvis at the very start of the downswing. However, note how much the lead shoulder moves in the last few frames and this is due to rotation of the upper torso that occurs secondary to activation of the core muscles of the mid-upper torso. I can readily imagine that rotation of the upper torso, and therefore the thoracic spine, synergistically helps to induce a continuing clockwise rotation of the pelvis as the downswing further evolves - but it doesn't require any lateral bend for this biomechanical phenomenon to manifest. Note that KM never discussed these biomechanical phenomena in his articles. In fact, consider what Jeffy claims causes the pelvic rotation that happens during the early downswing. See post #19 in this Jeffy-forum thread - jeffygolf.com/showthread.php?1089-Jeff-Mann/page2Jeffy stated in that post-: " More specifically, what does Kel say about the initiator of the pelvic motion? Could it be what Dr. Mann calls "pelvic girdle muscles"?" What pelvic girdle muscles is Jeffy referencing as being the initiator (causal agent) of the initial pelvic motion? Note that Jeffy posts extracts from KM's article - referencing dual hip flexion and left pelvic tilt. I personally disagree that they are causally responsible for the early pelvic rotation! I think that the iliopsoas muscle is not a pelvic girdle muscle and that any hip flexion phenomenon secondary to contraction of the iliopsoas muscle is a superadded biomechanical phenomenon that is not primarily responsible for causing the initial pelvic rotation (which is a rotary motion). I also think that KM is being wrongheaded when he states that the left iliopsoas muscle must contract to induce left pelvic tilt in order to initiate the initial weight shift to the left, and that this same biomechanical phenomenon is also necessary in order to induce a stretch-shorten cycle that will be needed to ensure that the left hip joint moves vertically upwards just before impact. There is world of difference between my understanding of what represents the most important biomechanical elements that are needed to induce pelvic rotation at the start of the early downswing - compared to Jeffy's understanding? Jeff.
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Post by imperfectgolfer on Aug 6, 2014 19:58:03 GMT -5
Jeffy posted this image of page 115 in his "Jeff Mann" forum thread Jeffy then stated-: " The action of the lateral rotaters is external hip rotation, i.e. to rotate the femur externally. Similarly, the gluteus medius actions listed below include abduction, external hip rotation and internal hip rotation, but no reference to transverse pelvic rotation." Jeffy then also stated-: " Mann follows with another gem:
Also, read the section on gluteus medius on page 117. It states that the posterior fibres externally rotate the pelvis when the ipsilateral femur abducts. How can Jeffy justifiably claim that the gluteus medius muscle is not positioned in a way that it can cause the pelvis to externally rotate in a horizontal plane?
Again, Dr. Mann incorrectly substitutes "pelvis" for "hip", creating an absurdity: the pelvis does not rotate internally or externally.
And Mann does it again, substituting "pelvis" for "hip", creating more nonsense:" (The bold-highlighted quoted statement was my original claim). Jeffy is asserting that I am misinterpreting that author's statements about the action of the 6 lateral rotator muscles. Jeffy is free to harbor a different opinion, but Jeffy goes even further and mounts an uncivilized ad hominem attack. This is what jeffy also stated in the Grant thread-: " Engaging with Jeff Mann is pointless. He unashamedly ignores reality; I think he could well suffer from a sort of schizophrenia where logic and truth telling doesn't exist.
For example, he has regularly claimed that the "pelvic girdle muscles" can cause the pelvis to rotate in the horizontal plane (called "transverse pelvic rotation"). To "prove" he was correct, Mann produced a text book chapter and claimed it showed he was right. In fact, the text showed that I was right: none of the pelvic girdle muscles where identified as causing transverse pelvic rotation. Incredibly, he identified muscles that control external rotation of the femur (called "external hip rotation") and pretended that movement was transverse pelvic rotation! He was "caught red-handed", yet he continues to deny he was wrong (as well as was deceitful)." He shamelessly labels me as being a "sort of schizophrenic" who is also "deceitful" and a "pretender" who deliberately substitutes words. That's typical of Jeffy's uncivilized/vulgar method of arguing. I don't mind him asserting that I misinterpret reality, but he (like Grant) calls me a liar because I have a different opinion. Do I have any justification for using the "pelvis" and not "hip joint" in my original statement? I deliberately chose the word "pelvis" because I believe that active contraction of the 6 left lateral rotators can not only produce external rotation of the left femur, but I believe that they can also cause left transverse pelvis rotation (which is equivalent to external rotation of the left hemipelvis). Where is my proof? The proof is right there on page 115 (see Jeffy's image above), and here is a closeup of the relevant paragraph on page 115. Look at the yellow-highlighted sentence where the author asserts that the contraction of the 6 lateral rotator muscles are powerful enough to " forcefully turn the body" which is even a greater degree of rotary movement than transverse pelvic rotation. In other words, a very active/forceful contraction of those muscles can obviously rotate the left pelvis (as occurs in Hogan's left hip clearing action" move) if the left leg is unweighted and not immobile, and if the left hemipelvis is relatively free-floating. If the pelvis was not free-floating, and if it was rigidly fixed in space, then contraction of those muscles would only produce external rotation of the left femur in the left hip joint. However, at P4, a pro golfer has 70-80% of his COP-measurement over the right foot, and only 20-30% over the left foot, and the left femur and left hemipelvis can freely move about in space, and they can both easily rotate counterclockwise in response to an active contraction of the 6 left lateral rotator muscles. I believe that Jeffy is misinterpreting that author's article! To confirm that I am likely correct, I am going to contact a number of biomechanists and pose that question to them. I will then post their response in this forum. Jeffy again accuses me of misrepresenting KM when he wrote-: " Another example from late last night illustrates so many of his loathsome traits. He has repeatedly stated that Kelvin's belief is that lateral bend and lordosis initiates the movement of the pelvis in the downswing, despite me directing him to Kel's article where Kel clearly states that contraction of the iliopsoas muscle (which pulls the pelvis and thigh together) is the initiator". Jeffy has given up defending his personally-stated opinion that the spine engine initiates the downswing's pelvic motion and now he claims that KM clearly states that contraction of the iliopsoas muscle (which pulls the pelvis and thighs closer together) is the initiator? However, what has that iliopsoas muscle action got to do with the topic of left transverse pelvic rotation (Hogan's "left hip clearing action" move)? Where does KM ever discuss the biomechanical mechanism underlying the "left transverse pelvic rotation" that is the "true" pelvic rotary move that Hogan asserted should start the downswing action? I cannot find any KM-discussion of this core downswing-initiating action in any of his articles. Can you? Jeff.
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Post by imperfectgolfer on Aug 7, 2014 10:47:54 GMT -5
I posted the following capture image. Jeffy responded as follows in his Jeffy-forum thread-: " He has it exactly backwards: externally rotating the left hip with a immobile left thigh will rotate the pelvis clockwise, away from the target. If the left leg is free floating, the left thigh will rotate towards the target, which happens during the squat into dual ER. Internal rotation of the left hip at the end of the downswing continues the rotation of the hips towards the target." Why does he think that the left thigh is immobile? In a pro golfer, the left thigh is not immobile, and it is relatively mobile (relatively free-floating). Under those conditions, the left thigh will rotate towards the target when a golfer activates the 6 lateral rotators of the lead pelvis? That muscle action should also cause the lead pelvis (which is rotated away from the target at the P4 position and which is also free-floating) to rotate counterclockwise. I am not inferring that the counterclockwise rotation of the lead pelvis between P4 and P5 is due to activation of the lateral rotators muscles of the rear pelvis, which is suspended over a relatively immobile right leg/foot. When I start the downswing and initiate the "Hogan left hip-clearing action" move, I contract the muscles in my left buttocks and not my right buttocks. If I try to activate the muscles in my right buttocks to start the downswing action, it causes my right pelvis to spin outwards, which is very undesirable. I try to keep my right buttocks against the tush line between P4 and P5 as I actively pull my left buttocks back towards the tush line. Also, when I stand on my right leg (as described in that yellow-highlighted sentence) - keeping my balance by holding onto a nearby structure (eg wall or table) - I move my body away from the standing leg by activating the muscles in my left buttocks, and not the right buttocks, as I try to "forcefully" externally rotate my left femur that is free-floating. That "forceful" attempt to externally rotate my left thigh actually causes my left hemipelvis to rotate counterclockise and my upper body also moves in the same counterclockwise direction. Jeff.
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Post by imperfectgolfer on Aug 9, 2014 11:03:51 GMT -5
Consider this video by Rob Houlding describing the motion of the pelvis in the downswing. vimeo.com/67192884Note that he thinks of starting the downswing by "feeling" that he pushes off the right leg. I think that he is using the lateral rotator muscles of his right hemipelvis, which will rotate the pelvis counterclockwise if the right leg is immobile. I believe that if a golfer simultaneously contracts the lateral rotator muscles of the left hemipelvis, that they can both act synergistically to cause left transverse pelvic rotation at the start of the downswing. So, one needs the combination of an immobile right leg and freely mobile left leg between P4 and P4.5 to best perform Hogan's left hip clearing action (which is equivalent to a left transverse pelvic rotation), using both the left-and-right lateral rotator muscles, at the start of the downswing. Those two muscle groups are perfectly positioned at P4 to initiate the rotary pelvic motion - even though Jeffy claimed that the pelvic girdle muscles are not correctly positioned to start the downswing in a horizontal plane of motion. Jeff.
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Post by imperfectgolfer on Aug 11, 2014 11:10:38 GMT -5
Grant has attacked me relentlessly in the following Jeffy-forum thread - jeffygolf.com/showthread.php?1214-Jeff-Mann-hides-the-evidence-whenever-he-is-caught-red-handedHe labels me a misrepresenter/liar who is incapable of telling the truth. If that is his "belief" then why does he even bother asking me questions about golf swing biomechanics/mechanics. He is particularly focused on the following question, which he bold-highlighted-: "j ust once dr mann? argue against our ACTUAL BELIEF.
here.... ill give you a perfect opportunity. are you ready? The ACTUAL belief of kelvin and most of the people on this forum is this: On a typical swing where there is left lateral bend at the top of the swing.... the stretch that will cause lateral bending to start going in the opposite direction SHOULD (NOT MUST) occur in transition. Right lateral bend will be visible later in the swing.... but the bending the other way started in transition. This is the move of players like Keegan Bradley for instance." If the right lateral bend only starts in transition, then there cannot be a significant amount of right lateral bend present between P4 and P4.5. That means that the spinal engine cannot be operating between P4 and P4.5. Grant claims that I am misrepresenting KM by claiming that the spine engine is operant during the P4 and P4.5 transitional time period. However, how can I be misrepresenting KM when he made this claim regarding Rory McIlroy's P4-P4.5 time period. KM posted this animated gif of Rory McIlroy. KM then stated-: "Here's an animation of Rory's right shoulder moving down in transition. This was shot at 300 frames per second and but I'm showing it as 150 frames per second so as to cut down on the amount of stills needed.
Approximately 24 frames of 300 fps video or .08 seconds worth of lateral bending occurs without any shoulder rotation at this point.
This gives the spine facets some time to connect before any rotation begins". I didn't make that bold-highlighted claim about the interfacet joints having time to interconnect during the P4 - P4.5 time period. Has KM subsequently disavowed his "claim" that the spine engine is operant during the P4 - P4.5 time period? Grant is also implying that right lateral bend only has to develop later (eg. at P5.5+) to legitimize the spine engine theory. However, any right lateral bend that develops in the mid-late downswing only causes side-compression of the lower thoracic spine (and not the lumbar spine) and the thoracic interfacet joints are flat and incapable of interlocking. Why doesn't Grant/Jeffy respond to this criticism? Jeffy has also claimed that the lateral bend is responsible for Bubba Watson/Jamie Sadlowski having a more open pelvis at impact - compared to the "average" pro golfer. However, I can think of three more plausible biomechanical reasons for that "fact" - i) BW/JS are more actively rotating their pelvis than the "average" pro golfer because they are more efficiently/actively using their pelvic girdle muscles to rotate their pelvis; ii) BW/JS rotate their upper torso much faster than the "average" pro golfer between P4.5 and P7 and that produces passive mechanical "torque forces" that are transmitted down the spine/paraspinal tissue to induce the pelvis to rotate faster; and iii) BW/JS are reverse-group golfers while the "average" pro golfer (like Grant Waite) is a front-foot golfer. A reverse group golfer only has 50% of his COP-measurement under his lead foot at impact, while Grant Waite has 90%. That means that Grant Waite's lead leg/foot is much more pressure-weighted, and therefore much more firmly immobile, between P6 and P7, and it is obviously much harder to rotate the pelvis under those conditions - for any given degree of muscular rotary power. Jeff.
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Post by imperfectgolfer on Aug 11, 2014 15:50:03 GMT -5
Grant wrote the following in the jeffy forum thread-: "You seem to long to be some great golf teacher. But you aren't even that good at applying your anatomy knowledge to the golf swing. And you have NEVER produced on elite level golf swing in yourself or anyone else."
It is fair enough to contest whether I am good at applying my knowledge of anatomy to the golf swing, and that's a mootable point that can be fairly debated. However, it is not mootable as to whether I have ever produced an elite golf swing in a student golfer because I don't teach golfers. It is also not mootable to debate whether I have an elite golf swing because I am too inflexible and too athletic to perform a golf swing even reasonably well. However, that doesn't mean that my "mind" doesn't know what my body should/must do if it were more flexible and more athletic, and if it could follow my mind's mental instructions. This argument has been previously brought up by Grant and it is a foolish argument that has no intellectual merit.
Jeff.
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Post by imperfectgolfer on Aug 19, 2014 9:31:31 GMT -5
See this Jeffy forum thread - jeffygolf.com/showthread.php?1237-Teenager-Victor-qualifies-for-Remax-World-Long-Drive-Championships-based-off-studying-kelvinGrant stated the following-: " i love the diversity among dynamic /drive hold swings that kelvin would be proud of. this is, of course, contrary to folks like jeff mann who would act as though kelvin preaches "one method" with no variation. i would say THERE IS A HUGE RANGE OF VARIATION.... polar opposites even among the swings we say are good. the one thing they all have is that they are athletic and use the spine." Grant is attempting to show that KM teaches a diversity of swing styles, but then he contradicts himself by saying that the one thing they all have in common is that they use the spine. Interestingly, that's one thing they do not use to power their swing - because there is no validity to the spine engine theory. That golfer (like Lucas or Jamie Sadlowski) rotates his pelvis primarily by using the lateral pelvic rotator muscles of his pelvis and he rotates his mid-upper torso using the core muscles of the mid-upper torso. The lumbar spine simply rotates in unison with the pelvic rotation and the thoracic spine simply rotates in unison with the upper torso rotation. The spine doesn't power the swing. The spine secondarily moves due to the activity of pelvic girdle muscles and mid-upper torso muscles. I am not surprised that Grant is so ridiculously wrongheaded, considering that he asked Jeffy for advice regarding his father's slow CH speed and received the following advice from Jeffy-: " One thing that helped was the Posture Pump, which I started using then (2010) and still use for 15 minutes three times a week. It hydrates the discs between the vertebrae, keeping the spine healthy and flexible."The "belief" in a the posture pump's ability to hydrate intervertebral discs and keep the spine healthy has no scientific validity. It's pure junk science! And, it is amazing that Jeffy had the audacity to tell Mike Duffey that he was not welcome in the Jeffy-forum because he hadn't published enough articles related to golf swing biomechanics. Mike Duffey may not have published many articles on golf swing biomechanics, but he was at least a "real scientist" rather than a "junk scientist" who believes that the spine engine initiates, or powers, the downswing and who believes in the scientifically-unproven value of the posture pump. Jeff.
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Post by imperfectgolfer on Dec 24, 2014 20:33:41 GMT -5
See this Jeffy forum thread - jeffygolf.com/showthread.php?1363-Congratulations-Andy-Plummer-Stack-and-Tilt!&p=11888#post11888 Note that Jeffy stated that lateral bend will only cause rotation of the lumbar spine/pelvis in the opposite direction if the lumbar spine is in lordosis. That's factually incorrect and he is simply referring to his "spine engine" belief. Jeffy even tried to show that more recent medical studies have confirmed this fact. Ths is Jeffy's quote in post #698 of the Golf WRX.com thread - see www.golfwrx.com/forums/topic/1082799-kelvin-miyahira-pro-or-con/page__st__690" Much research has been done since the days of Fryette. More recent research states that lordosis is a prerequisite for contralateral rotation from lateral bending of the lumbar spine, and that flexion of the lumbar spine and lateral bend will cause rotation in the same direction (ipsilateral rotation). For example, Pearcy MJ, Tibrewal SB. Axial rotation and lateral bending in the normal lumbar spine measured by three-dimensional radiography. Spine 1984:9:582-587. and Panjabi M, Yamamoto I, Oxland T, Crisco J. How does posture affect coupling in the lumbar spine? Spine 1989; 14:1002-1011. " Note that Jeffy has again claimed that the lumbar spine must be in lordosis in order to get contralateral rotation from lateral bending. However, Jeffy used selective studies to reinforce his wrong-headed belief. Here is a list of all the scientific studies that have been performed. perfectgolfswingreview.net/CoupledMotionLumbarSpineStudy.jpg" alt=" "] Here is a link to the pdf format of the article (from which this literature review image was derived) - www.shelbournephysio.ca/images/uploads/79/coupledmotions.pdfNote that the studies show either no effect or a contralateral rotation effect secondary to lateral bend. Also, note that the contralateral (opposite) effect is seen irrespective of whether the lumbar spine is neutral, or in flexion or extension (lordosis). In particular, Jeffy quoted Panjabi, but note Panjabi's results - which show that opposite rotation occurs throughout all ranges of lumbar flexion/extension. Jeff.
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Post by lumbarjack on Jan 30, 2015 18:30:27 GMT -5
Hello This is serge gracovetsky, and I saw this forum for the first time. What strikes me is the hard language used by Jeff against anyone that does not agree with him. Accordingly, I will not spend time arguing everything except to suggest that getting informed is the best course of action. Indeed, ignorance is generally not a prerequisite for rationale debate. As a first example (and possibly my last here) I suggest the reading of chapter 8 of my book "The spinal Engine" that is titled "The gearbox of the spinal engine”. Here Jeff will belatedly discover (what I publicly released in 1985 - 30 years ago !!) why a lateral bend to the left may or may not induce an axial rotation to the left, may induce a rotation to the right or no rotation at all. The control of the switching is done by the positioning of the instantaneous center of rotation and in that chapter I explain how this is done. The various studies indicated in Jeff’s post of December 2014 can be understood by the simple fact that these studies did not control the position of the center of rotation and hence everything becomes possible. That is unfortunately the norm in the business. Did you know that the function of the lumbar spine was deduced by some famous people by studying the motion of the cervical spine of pigs? No joke here. I have the reference if you want. The authors pushed the ridicule to a level never seen before by writing that “. If I showed a pig neck or vertebra to a human surgeon, and we do this in the lab, they don’t know whether it’s a pig C4 or a lumbar C4 out of a human. They are that close.” I beg to differ. Even if I was called a “male chauvinist pig” in my younger times, I maintain the heretic view that there is a fundamental difference between a pig and (most) men with perhaps the exception of some politicians. This demonstrates that medicine is perhaps the only human activity where an attractive idea will survive experimental annihilation. Not good, but real. Anyway…. If anyone is interested in the real thing, directly from the horse’s mouth, then I invite them to come to Washington on September 15, 2015 for the fourth conference on fascia research. I will be holding a full day seminar on the function of the spine. That is, I will spend a minimum of six hours (with 400 slides and movies) explaining how the spine works and get injured. That complexity is the reason I am reluctant to spend hours in sterile arguments on this forum analyzing and speculating on spinal motions hidden by the clothing of various golfers. I wish you all the best and perhaps will see you in beautiful Washington this fall. www.fasciacongress.org/2015/program/conference-program/Warm regards to all Serge
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Post by imperfectgolfer on Jan 31, 2015 0:19:16 GMT -5
Serge, You wrote-: " Did you know that the function of the lumbar spine was deduced by some famous people by studying the motion of the cervical spine of pigs? No joke here. I have the reference if you want. The authors pushed the ridicule to a level never seen before by writing that “. If I showed a pig neck or vertebra to a human surgeon, and we do this in the lab, they don’t know whether it’s a pig C4 or a lumbar C4 out of a human. They are that close.” I beg to differ. Even if I was called a “male chauvinist pig” in my younger times, I maintain the heretic view that there is a fundamental difference between a pig and (most) men with perhaps the exception of some politiciansThis represents your usual comedic method of arguing as evidenced in your lecture to the fascia congress. That's a worthless argument and it doesn't deal with the relevant "facts" that I have written about ad nauseum. You have not shown that I am wrong regarding my criticism of your "spine engine" theory by presenting a coherent counterargument. I summarised my opinions regarding the "spine engine theory as it pertains to a golf swing" in topic number 1 and topic number 6 of my latest review paper - perfectgolfswingreview.net/spinalmotion.htm - and you are free to criticise my opinions if you want to present a counterargument. Jeff.
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Post by imperfectgolfer on Apr 16, 2015 9:56:14 GMT -5
See this Jeffy-forum thread - jeffygolf.com/showthread.php?1490-Coupled-Motion-of-the-Spine-in-SportsMax Propkopy stated-: " I'm sure many people misrepresent his work...people do the same for McGill all the time. What I'm less certain of is which "version" Gracovetsky wants to to promote himself? His ideas might even be self-contradictory...my hope is they evolved over time because he presents no evidence of this "gear effect" from the facets themselves. For example: the thoracic spine also experiences spine coupling but does not have the facet anatomy to interlock in anywhere near the same capacity. Yet, the coupled thoracic motion is arguably greater. The troubling part is that none of these works are peer-reviewed and he presents no evidence for this aspect of the theory. For obvious reasons, people were pretty skeptical about that. Clearly a very smart man but it's easy to see how he became marginalized. Just so you understand, I don't care about marginalizing him, I care about evaluating the ideas. " Max is seemingly smart enough to question the validity of Serge Gracovetsky's "junk science" opinions, which could never survive peer-review by "true scientists". I bet that Max will eventually be banned from Jeffy's forum - because Jeffy doesn't countenance criticism of his beloved "spine engine" theory. Jeff.
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Post by imperfectgolfer on Apr 18, 2015 10:52:59 GMT -5
When Max Prokopy expressed scepticism about the "interlocking gears" concept in the Jeffy-forum thread, Jeffy replied as follows-: " Max,
Have you read chapter 8 of The Spinal Engine yet? The interlocking facets are described as the "gearbox", and the "engine" is the musculature and fascia.
Except, the gearbox isn't exactly interlocking facets (page 148):
"As the right facets make contact, (or more realistically, as the cartilage between the bones is sufficiently compressed)..." Note the bold-highlighted claim about "sufficient compression of the cartilage" lining the right-sided lumbar interfacet joints. If that truly happened in a pro golfer's swing, then the pro golfer would likely end up with severe osteoarthritis of the interfacet joints after a few decades because the cartilage would be worn-away with the passage of time. I don't believe that a large amount of cartilage compression of the interfacet joints happens in a pro golfer's downswing - because I don't believe that the right lateral bend is actively torquing the lumbar spine when the right-sided lumbar spine interfacet joints become compressed - which only happens between P6 and P7. Consider this diagram used by KM. Note that he is showing compression of the right-sided lumbar interfacet joints that only happens when the lateral bend involves the lumbar spine. But, when does the lumbar spine get affected by the right lateral bend phenomenon? It doesn't happen between P4 and P6 because any right lateral bend (that may be present) only affects the thoracic spine, and not the lumbar spine. Right lateral bend affecting the lumbar spine only happens in some pro golfers between P6 and P7. Which pro golfers? Consider this image of 5 pro golfers at impact. Image 3 shows Phil Mickelson who has virtually no right lateral bend. Image 1 and 2 show Alvaros Quiros and JB Holmes with a moderate amount of right lateral bend that only affects their thoracic spine and not their lumbar spine. Image 4 and 5 show Hunter Mahan and Keegan Bradley with a far greater amount of right lateral bend that also affects the lumbar spine, and not only the thoracic spine. The reason is that they both have i) an open pelvis, ii) have their clubshaft and therefore their hands in a low position (below the elbow plane), and they both have iii) their right forearm nearly horizontal. To come into impact with those impact alignments requires a lot of right lateral bend that will also affect the lumbar spine, and not only the thoracic spine. So, do I believe that their right-sided lumbar interfacet joints are being markedly compressed to a degree that will cause significant compression of the cartilage lining those joint surfaces, and that will predispose them to premature osteoarthritis of their lumbar interfacet joints? The answer is negative! The reason for my opinion is that the right lateral bend affecting the lumbar spine only happens between P6 and P7 and it happens when the pelvis is naturally slowing down, and I believe that their pelvic rotation is not being actively driven by an axial torque generated by right lateral bend during that time period (as claimed by KM and Jeffy). If it was, then the likelihood of premature osteoarthritis of the interfacet joints would probably increase dramatically in golfers (like HM and KB) who use that technique. I believe that the "interlocking gearbox" concept is an imaginary concept that has never being verified in scientific testing. Here again is the article describing all the research studies on the coupling motion. www.shelbournephysio.ca/images/uploads/79/coupledmotions.pdfIf you read the article, you will see that the researchers have not even definitively concluded what causes the coupling phenomenon from a biomechanical perspective, and there is no scientific evidence that proves that the coupling phenomenon occurs due to unilateral compression of the lumbar interfacet joints (which is the theoretical basis for the "spine engine" theory's "interlocking gearbox" belief). Jeff.
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