McLeans' X factor

[JeffMann]

Robby

I apologise if I have offended you. I actually very much welcome your expertise. I am very respectful of [b]true [/b]expertise and if you can contribute useful scientific knowledge to this debate, it may change many minds (like mine). I am simply stating that I think that the X-factor is seemingly based on junk science rather than real science (which I basically define as rigorous scientific experimentation where the design experiment minimises the presence of confounding variables and where the scientist's conclusion is proportional to the experiment's design parameters - scientific conclusion must only relate to the primary hypothesis being tested).

Regarding the elastic properties of tendons. I was not implying that tendons have zero elastic properties. I was implying that tendons do not act as elastic structures designed to store and release energy, and that they do not therefore contribute significantly to work output. Consider the example I gave in another post about a knee extension exercise action. During that movement, the patellar tendon is stretched when the person slowly relaxes the active knee extension so that the knee can bend back to its rest position. I believe that any stretch of the patellar tendon doesn't store [b]significant[/b] energy in the patellar tendon (via its elastic properties), which the tendon can subsequently release during the next muscle contractile movement. Please correct me if you think that I am wrong, and tell me how much of the work output in the next knee extension action is due to elastic power stored by the patellar tendon?

Regrding that journal article, the experimenters were seemingly trying to see whether repetitive muscle contractions could affect a tendon's ability to be compliantly stretched. If the tendon is stretched, it obviously implies a certain degree of elasticity in the tendon. However, the experimenters did not demonstrate the [b]significance[/b] of that elastic stretch phenomenon. They supplied no reference values that would allow me to judge the[b] clinical significance[/b], rather than the statistical significance, of their research results.

You state that you are not personally involved in golf-research. However, have you seen any scientific research papers underpinning McLean's X-factor claims? Are those studies scientifically rigorous - in the sense that they significantly eliminate the problem of confounding variables?

I hope that you continue to contribute to this debate, because with your background expertise, you could make a[b] major [/b]contribution to scientifically-based opinions, rather than authority-based opinions, and help us better understand whether the X-factor is based on real science rather than junk science.

Jeff.

[JeffMann]

HF/Points

You are both implying that MA had a large X-factor. That's my point-of-contention. MA swung in a certain biomechanically efficient way - where the shoulders turn much more than the hips. MA's swing style is simply a product of efficient human biomechanics during a full golf swing. That's how the body moves optimally in space when executing a full golf swing. The X-factor implies that a [b]significant[/b] amount of MA's swing power comes from [b]stretch[/b] and not from the alignments/ body positions/degree of body rotation adopted by MA during his swing. That's the true issue-of-contention - differentiating stretch-induced force enhancement from those other factors, so that one can scientifically quantitfy the contribution of stretch!

Jeff.

[Jrose]

Didn't McLean also do an article on the "Y" factor couple years ago?

[Points]

Jeff,

Again, even further proof that you are not grasping the concept of the X factor. What the x factor states is that there is a difference between the amount the hips and shoulders turn. In all swings, the shoulders will turn more than the hips. For the player who turns his hips 60 degrees and his shoulders 65 degree, there is an x factor of 5. Assuming the player has no physical limitations, he is not maximizing his distance potential.

The x factor stretch or two way motion refers to the change in direction. During the transition, there is a small amount of time when the hips move first and the shoulders are either moving back or are still. When this occurs, your X factor stretches or increases. Meaning that static difference at the top might be and the difference during the downswing between hips and shoulders might be 20. You would not want an x factor of 15 at the top and as you start down the difference decreases right away. The reason that the stretch is important is that helps mazimize when certain areas of the body reach their peak speed thus trasfering the energy into the clubhead and to the ball. You would not want your hips or your shoulders to reach max speed when the club first starts down.

[JeffMann]

Points - I think that it is you that doesn't understand the X-factor (not me). You state "For the player who turns his hips 60 degrees and his shoulders 65 degree, there is an x factor of 5." That's true. And if the golfer turns his shoulders 90 degrees, then his X-factor figure is 30. That larger X-factor translates into a longer driving distance, but I believe that the [b]extra[/b] distance is simply due to a greater degree of shoulder rotation and therefore an enhanced ability to swing the clubshaft at a faster speed, and that it is not due to any stretch-induced force enhancement of torso muscle contractile power. Golfers who have large X-factors have much better body positions/alignments, and therefore better biodynamics, than golfers with low X-factors, and it is those factors that result in greater swing power - not stretch!

Jeff.

[Texsport]

The comparison of baseball and golf swings for utilizing X-factor physics for power is very valid.

Just as Hogan increased X-factor(torque) by starting his lower body back to the ball before he completed his upper body backswing, so did Ted Williams **** his upper body away from the pitcher as he began striding.

[url="http://www.youtube.com/watch?v=JwogLVGtDa8&feature=related"]http://www.youtube.com/watch?v=JwogLVGtDa8...feature=related[/url]

Another player who clearly utilizes this move is Manny Ramerez---a current Red Sox slugger who generates tremendous power dispite being a normal sized guy.

[url="http://www.youtube.com/watch?v=iS4tvvPgbKk"]http://www.youtube.com/watch?v=iS4tvvPgbKk[/url]


And , of course, there is the One Plne, X-Factor, Rotational Torque batting technique!

[url="http://www.youtube.com/watch?v=Byuht5bfR20&feature=related"]http://www.youtube.com/watch?v=Byuht5bfR20...feature=related[/url]

So, this idea is nothing new to baseball guys.

Texsport

[JeffMann]

Texsport

It is true that Hogan (and many pro golfers) move their lower body back towards the target before the upper torso has completed its backswing movement. However, I am not aware of any research that demonstrates how much that [b]tendency[/b] contributes to [b]total[/b] swing power. There are many pro golfers who don't have that [b]particular[/b] dynamic X-factor feature, and I have never seen any studies that quantify what effect that "difference in swing style" will have on driving distance. Have you?

Jeff.

[Veritas]

Ok so I am on a quick lunch break and wanted to do a quick dive into the literature and found this article that I think is relevant to the current discussion
[url="http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=17852693&ordinalpos=26&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum"]http://www.ncbi.nlm.nih.gov/sites/entrez?D...Pubmed_RVDocSum[/url]

I have only looked at the abstract so far but will try and download the article and get a good read on it later.

As a reference, if you are looking for papers on these subjects go to www.pubmed.org. Just do a search on golf and you will find a lot of papers on the subject. I for one am going to look at reading some when I get the chance.

[JeffMann]

Jarid

I read section 5 in that pdf article by Rob Neal. He basically states that if the shoulders turn 40-50 degrees more than the hips that the abdominal oblique muscles are stretched. That's true. However, he doesn't actually present any scientific data to show how much more effectively the abdominal muscles contract if they are more stretched (X-factor of 50 degrees) than less stretched (X-factor of 30 degrees). He also doesn't demonstrate whether [b]over-stretching [/b]can actually decrease muscle power. Consider two examples.

Tiger Woods has a hip turn of 30 degrees and a shoulder turn of 100 degrees. His X-factor is 70. Sam Snead had a hip turn of approximately 60 degrees and a shoulder turn of 110 degrees. His X-factor is 50. One could (falsely) conclude that TW's greater X-factor will result in greater swing power, but that belief requires proof. It could well be that TW is over-stretching his abdominal obliques and under-stretching his pelvic/gluteal/thigh muscles - compared to Sam Snead. Sam Snead's bigger hip turn may also allow him to have better downswing dynamics than TW - for biomechanical reasons other than those due to torso muscle stretching.

Jeff.

p.s. By the way, I have communicated with Rob Neal by email and by telephone earlier this year - when we discussed his paper on the S&T swing.

[JeffMann]

Robby - that looks like it could be an excellent paper and worth reading. Keep up the good work, and provide us with more scientifically-based research material. I would very much appreciate it if you could send me a full text copy of the article by e-mail - [email protected] . If we both read the article carefully, then we can fruitfully debate the study's scientific strengths/weaknesses and the scientific validity of its conclusions.

Jeff.

[Points]

Based on your statement, the range of motion of the shoulders is what creates the distance boost not the realtionships with its hip. So a swing with 90 degree of shoulder turn and 80 degree of hip turn will hit it the same distance as someone with 90 shoulder and 45 hip as well as someone with 90 degree of shoulder and 20 degree of hip turn. I don't know about anyone else reading this thread but when I see the statement with numbers it looks a bit silly.

Finally, trying reading stretch as increase or widen the difference and not the medical version.

[Veritas]

ugh...Neither Cornell's library nor Penns library has a subscription to this journal. I will try some other avenues but I don't know that I can get this article without paying for it. Anyone else at a college with a sports science department that might subscribe to this journal out there?

EDIT: I have made an interlibrary loan request for this article so hopefully they will be able to find it and get it to me.

[Veritas]

As for tendons functioning as an energy storage structure. There is actually a decent amount of evidence that this happens. What is mostly seen is that this is extremely relevant in large mammals and not as much in smaller animals. An elephant when running has tendons providing around 60% of the work for locomotion. There is even around a 90% work load done by tendon in kangaroos when jumping. The reason for this is based on the size of muscle and the loads that can be put on the tendon. However, our muscles are no where near the size of an elephant, obviously, and so we will not get nearly such a high affect due to not putting such high loads on the tendon. However, there are studies showing that during walking the gastrocnemius tendon provides around 6% of the work in the locomotive system and would be higher if running. So I'm currently trying to find load values in the torsional stretch to see what kind of work we could expect in the tendons under torsional stretch. I don't think it is an unreasonable estimate to say that we would see at least a couple of percent contribution from stored energy in the tendons; however, this is yet to be determined. There is also the argument that a stronger golfer could produce a larger stress on these tendons and cause a greater amount of energy to be stored in the tendon. As a result, stronger golfers could store more energy in tendons when increasing there x-factor. Just some thoughts.

[caryk]

Here’s some more interesting stuff and food for thought on the subject. This is an excerpt from an article published in the December 1999 issue of Golf Tips magazine by Jeff Parks at GolfTEC. He looked at Jim McLean’s research on the X-Factor and thought that lost in McLean’s theory was the need to create an efficient X-Factor, not simply a large one. He felt that an efficient X-Factor would allow a player to hit longer, more accurate shots – without having to swing any harder. (BTW, I’ll try to scan and post the entire article as soon as I can):

[color="#0000FF"]“Most amateurs think that the farther back they turn, the more power they’ll get, which is only partially true. Power doesn’t come from how much you rotate your shoulders. Power results from 1) separating your shoulders from your hips on the backswing, and 2) by how fast you turn them towards the target to release the energy on the downswing.

A common misperception is that a golfer must turn his or her shoulders at least 90 degrees on the backswing in order to get good power. This is only true if you’re flexible enough to do, i.e., have the ability to turn your shoulders without turning your hips. Many weekend golfers and amateurs will try to turn their shoulders 90 degrees, and when they can’t get there, they turn their hips, which reduces their X-Factor and kills their power. It’s much better to have a reduced shoulder turn, say 80 degrees or whatever your body can handle, and keep your hips still, which creates a larger separation (and X-Factor).

If your shoulders turn 90 degrees on your backswing, and your hips turn 45 degrees, you have an X-Factor or 45 degrees. If you turn your shoulders 120 degrees on the backswing and your hips 75 degrees, your X-Factor is still 45 degrees – two different rotations, one X-Factor. But the latter is much less efficient. The inefficiency results because you have a much greater distance to turn your hips and shoulders back to the ball to create a powerful position at impact.

To measure the efficiency of your X-Factor, take the difference between your shoulder and hip turns, then divide the result by the degrees of shoulder rotation. For example, an X-Factor with 89 degrees of shoulder turn and 48 degrees of hip turn gives an efficiency percentile of 46 [(89-48)/89 = 0.46 or 46%]. With this formula, the closer a golfer gets to 50% (or more), the more efficient his or her X-Factor.

Let’s take a look at the same degree of separation, but with a larger turn. Taking 120 degrees of shoulder turn and 75 degrees of hip turn, we get an efficiency rating of 37.5% [(120-75)/120 = 0.375]. To grasp this in simpler terms, think of how you throw a baseball. You reach back to build up potential energy, but if you reach too far back or turn too far around, it takes most of your energy just to get back to your starting point before you can release the ball. The golf swing is just the same. There’s a range on your backswing to which you can rotate, but if you go too far, you’ll lose your balance and waste most of your energy trying to get back to the ball.

Most recreational players can’t get an X-Factor to exceed 20 or 30 degrees much less 41 degrees that the pros average. Obviously, they’re turning their hips too much and their shoulders too little, which kills the efficiency of their X-Factor.

Professional golfers X-Factors that were measured:
Stewart Cink … Shoulder turn (83°), Hip turn (36°) = X-Factor (47°) and Efficiency Rating of 57%
Skip Kendall … Shoulder turn (104°), Hip turn (48°) = X-Factor (56°) and Efficiency Rating of 54%

Key point is … in order to develop the most efficient X-Factor, you need to limit the rotation of your hips and maximize the rotation of your shoulders. A secondary point is that the less you’re able to rotate your shoulders (in response to physical limitations), the less you should rotate your hips.

These guidelines are served up in response to the requirements of impact – the moment of truth in the golf swing. At impact, you want to get both the shoulders and hips about 40 degrees open, like Skip Kendall, whose hips and shoulders we measured at 44 and 47 degrees open at impact, respectively. Skip’s strong position at impact is a major reason for his scoring consistency. Most amateurs don’t even sniff these numbers for one very simple reason: When you rotate too far back on the backswing, there’s simply not enough time in the swing to get your hips and shoulders open at impact. That’s why we advocate a reduced backswing, but a stronger X-Factor and efficiency rating. Not only is the energy more efficiently stored, you’ll have more time to get the shoulders and hips wide open at impact.”[/color]

[Texsport]

[quote name='JeffMann' post='822938' date='Dec 13 2007, 10:53 AM']Texsport

It is true that Hogan (and many pro golfers) move their lower body back towards the target before the upper torso has completed its backswing movement. However, I am not aware of any research that demonstrates how much that [b]tendency[/b] contributes to [b]total[/b] swing power. There are many pro golfers who don't have that [b]particular[/b] dynamic X-factor feature, and I have never seen any studies that quantify what effect that "difference in swing style" will have on driving distance. Have you?

Jeff.[/quote]


Jeff

Of course not----that's why we're discussing it here! But why else study the swing methods of the greats if their methods are solely individual idiosyncrasies, not useable by any other person?

The evidence I listed is intended to suggest that the similar mechanics used by great baseball sluggers and one of the all time great golfers represents a method with proven success in more than one individual case. This is one way to do it---not the only way---but one that works/worked similarly for great players.

I would say that there are many ways to hit a golf/base ball----as many ways as there are golfers/bb players. Different methods fit the individual needs and levels of development of each player. But very few players excell at their sports. These are three examples of players who did/do excell. The proof is in the doing!

I would further suggest that these primere athletes use/d very little extraneous movements or devices in their swings that they didn't believe were helpful to their performances.

To suggest otherwise would claim that this common bio-mechanical movement was developed accidentally, and independently, while offering no advantage to each world class athlete----just a little too coincidental for credibility to my mind.

I chose to believe that they knew what they were doing--and why. That is precisely why they were/are all-time greats.

Texsport

[bennycoop9882]

Caryk- interesting stuff. I only had a question about the two professionals mentioned.

Stewart Cink: Shoulder Turn (83 degrees) Hip Turn (47 degrees)= (83-47/83)*100=[b]43.3 percent efficiency[/b]
Skip Kendal: Shoulder Turn (104 degrees) Hip Turn (48 degrees)= (104-48/104)*100=[b]53.8 percent efficiency[/b]

[JeffMann]

Points - you write-: "Based on your statement, the range of motion of the shoulders is what creates the distance boost not the realtionships with its hip. So a swing with 90 degree of shoulder turn and 80 degree of hip turn will hit it the same distance as someone with 90 shoulder and 45 hip as well as someone with 90 degree of shoulder and 20 degree of hip turn."

You totally misunderstand my position. I don't believe in the X-factor whether expressed as an absolute value or a percentage. I simply believe that the torso turn in a golf swing is near-exactly the same type of torso turn as occurs when skipping stones or performing a side-throwing action (eg. baseball pitching). I think that one should adopt an end-backswing position that will optimise the ability of the body to perform a good downswing torso pivoting-rotational motion. I therefore believe that one should turn the hips about 30-60 degrees, and the shoulders about 90+ degrees. I believe that a shoulder turn of 100-110 degrees is only suitable for a golfer who can maintain his clubshaft on plane and prevent any disconnection between the arms and upper body during that extra 20 degrees of shoulder travel. I don't think that there is any [b]direct[/b] correlation between the degree of differential turn (difference between the degree of turn of the hips and shoulders) and swing power. I think it depends on the physique, athletic ability, and time-coordination of body movements that an individual golfer can achieve, and I think that it should be tailored for each individual golfer. I also think that the idea of starting the downswing with a lower body move[b] before [/b]the backswing is complete is a good move for [b]many[/b] golfers, because it results in a more coordinated and more powerful downswing action that can result in greater swing power - but that this increased swing power is not due to any stretch phenomenon (dynamic X-factor), but rather due to better coordination of movements between the upper and lower body that allows the [b]entire torso[/b] to better act as a synchronised torso-rotational unit during the downswing.

Jeff.

[caryk]

Benny,

Good catch!!!

Looks like I typed the wrong numbers for that. No wonder it didn't make any sense to you. I corrected it in my previous post. Glad it wasn't a math exam. Probably explains why I'm not a rocket scientist ...

Thanks for bringing that to my attention.

[JeffMann]

Robby - if you theorised that a strong golfer could store 1-5% of his potential downswing swing power by stretching torso muscles/tendons during the backswing, I wouldn't bother to question the scientific legitimacy of that figure. However, I would seriously question the legitimacy of any postulated value above 5% and I would probably request scientific proof.

Jeff.

[caryk]

"A swing with 90 degree of shoulder turn and 80 degree of hip turn will hit it the same distance as someone with 90 shoulder and 45 hip as well as someone with 90 degree of shoulder and 20 degree of hip turn."

Here's how the "efficiency" rating would be for those three swings according to the GolfTEC article:

90° shoulder turn with 80° hip turn = (90-80)/90 = X-Factor of 10° and efficiency rating of 11%
90° shoulder turn with 45° hip turn = (90-45)/90 = X-Factor of 45° and efficiency rating of 50%
90° shoulder turn with 20° hip turn = (90-20)/90 = X-Factor of 70° and efficiency rating of 78%

So presumably, the last swing (90°/20°) would be the best and provide the most power.

[christhebigsmokemoss]

This might be the best way to increase power but it is also the best way to increase injury!

[jaridyard]

[quote name='JeffMann' post='822993' date='Dec 13 2007, 05:43 PM']Robby - that looks like it could be an excellent paper and worth reading. Keep up the good work, and provide us with more scientifically-based research material. I would very much appreciate it if you could send me a full text copy of the article by e-mail - [email protected] . If we both read the article carefully, then we can fruitfully debate the study's scientific strengths/weaknesses and the scientific validity of its conclusions.

Jeff.[/quote]

Jeff,
If you get a copy of that paper could you forward to me? Please PM for my email
Jaridyard

[Veritas]

[quote name='jaridyard' post='823252' date='Dec 13 2007, 04:14 PM'][quote name='JeffMann' post='822993' date='Dec 13 2007, 05:43 PM']Robby - that looks like it could be an excellent paper and worth reading. Keep up the good work, and provide us with more scientifically-based research material. I would very much appreciate it if you could send me a full text copy of the article by e-mail - [email protected] . If we both read the article carefully, then we can fruitfully debate the study's scientific strengths/weaknesses and the scientific validity of its conclusions.

Jeff.[/quote]

Jeff,
If you get a copy of that paper could you forward to me? Please PM for my email
Jaridyard
[/quote]

Sorry guys but I just got an email from the library and the article just came out and is not available through the interlibrary loan service. So unless someone wants to pony up the $25 we are not going to be able to read it right now. I can try again in a couple of months probably but for now we are out of luck. Sorry to disappoint.

[Points]

Jeff,
In your last post, you post NOTHING which is factual. Instead, you use words like think and believe often to substantiate your claims. There is no research at all to support your ideas. The ideas, research, and facts are out there regarding the X factor. If you want to PROVE it wrong, you are more than welcome to. Buy a K Vest, a launch monitor, and use some of your students. I would suggest using some of the top players in the game as well to futher validate your research. You could actually revolutionize the game in this undertaking as most all within the golfing community recognize that a relationship exits between the hips and shoulders.

[Veritas]

[quote name='JeffMann' post='823216' date='Dec 13 2007, 03:50 PM']Robby - if you theorised that a strong golfer could store 1-5% of his potential downswing swing power by stretching torso muscles/tendons during the backswing, I wouldn't bother to question the scientific legitimacy of that figure. However, I would seriously question the legitimacy of any postulated value above 5% and I would probably request scientific proof.

Jeff.[/quote]

Jeff,

Ok lets go with 1-5% then. So lets consider one golfer and say that if he swings with a small x-factor and stores only 1% of energy in the tendons and swings at 100 mph but also can swing and store 5% energy in the tendons with a large x-factor and swing at 103.125 mph as a result of the increased energy being stored (everything else being equal). Then using the generalized calculation of swing speed X 2.450 = carry distance, the swing with a larger x-factor will carry 252.66 while the lower x-factor will give you a carry distance of 245. Thats a difference in almost 8 yards of carry. I find that to be quite significant considering we are only talking about the elastic storage of energy and nothing else. I know I wouldn't mind picking up 8 yards.

[Points]

[quote name='rdbivyleagun' post='823397' date='Dec 13 2007, 05:58 PM'][quote name='JeffMann' post='823216' date='Dec 13 2007, 03:50 PM']Robby - if you theorised that a strong golfer could store 1-5% of his potential downswing swing power by stretching torso muscles/tendons during the backswing, I wouldn't bother to question the scientific legitimacy of that figure. However, I would seriously question the legitimacy of any postulated value above 5% and I would probably request scientific proof.

Jeff.[/quote]

Jeff,

Ok lets go with 1-5% then. So lets consider one golfer and say that if he swings with a small x-factor and stores only 1% of energy in the tendons and swings at 100 mph but also can swing and store 5% energy in the tendons with a large x-factor and swing at 103.125 mph as a result of the increased energy being stored (everything else being equal). Then using the generalized calculation of swing speed X 2.450 = carry distance, the swing with a larger x-factor will carry 252.66 while the lower x-factor will give you a carry distance of 245. Thats a difference in almost 8 yards of carry. I find that to be quite significant considering we are only talking about the elastic storage of energy and nothing else. I know I wouldn't mind picking up 8 yards.
[/quote]

I like the simple math but I am sure there will another and but from Jeffman

[JeffMann]

Points - you write-: "In your last post, you post NOTHING which is factual. Instead, you use words like think and believe often to substantiate your claims. There is no research at all to support your ideas. The ideas, research, and facts are out there regarding the X factor. If you want to PROVE it wrong, you are more than welcome to. Buy a K Vest, a launch monitor, and use some of your students. I would suggest using some of the top players in the game as well to futher validate your research."

Amazing comment! My ideas are noting more than a reflection of the research that has already been done on the golf swing. The Swing Like A Pro authors - Ralph Mann and Fred Griffin - studied the swing pattern of hundreds of golfers using high speed cameras and sophisticated computer analysis, and they reported their findings in their book "Swing Like A Pro". My swing model is not any different to their ModelPro swing model, and it simply reflects the swing style of most PGA tour golfers. Their ModelPro swing model is typical of most PGA tour golfers playing today. That swing model is also compatible with a large X-factor. The only point I have disputed regarding the X-factor is that it is due to "muscle/tendon stretch phenomena" rather than due to good biomechanics and good biodynamics that allow the golfer to use his upper and lower body as a synchronous torso pivoting/rotating unit. If anybody believes that it is due to coiling/uncoiling of the body, or due to stretch-induced force enhancement, then the onus is on them to prove their point.

Jeff.

[JeffMann]

Points - I was reading through all the posts again. I may have misunderstood your point of view. If you define a large X-factor as merely being a large difference in shoulder turn relative to hip turn, and that you believe that a large differential in the degree of shoulder-hip turn rotation will increase swing power, then I fully agree with you. In that sense, if you also argue along the following lines - that if two golfers have the same degree of hip turn of 45 degrees, then golfer A who has a shoulder turn of 110 degrees will likely hit the ball further than golfer B who has a shoulder turn of 90 degrees, then I fully agree. The only point about the X-factor theory that I find conjectural is the question of why a large X-factor causes increased swing power. I regard conjectures along the lines as "stretch-induced force enhancement" as being very problematic because I cannot picture which muscles are being stretched, and why it should increase swing power. I personally think that a large X-factor usually implies a bigger shoulder turn and those golfers usually also have more efficient downswing biodynamics (faster shoulder/hip rotation in the downswing). I see that combination-phenomenon all the time in the long ball hitters at my local golf practice facility - the long hitters have a bigger shoulder turn and they also have much faster torso rotation during the downswing. That's what makes them great long hitters! I think that the combination of a greater shoulder turn (10-20 degrees greater) during the backswing and a much faster shoulder/hip rotation during the downswing makes them hit the ball much further. It is only the coil/uncoiling theory relating to stretching muscles/tendons that I find questionably scientific (junk science), and not the simple fact - that a bigger shoulder turn +/- faster torso rotation will increase swing power.

Jeff.

[hoganfan924]

Backpedaling now are you, Doc?

Jeff,

[b][i]You[/i][/b] started this entire thread with the following statement:

[quote]HF

[b]I read that McLean article [/b]about the triple X-factor in the GD.

I don't think that there is much new - its only the idea of a dynamic X-factor rather than a static X-factor.

[b]I have changed my thinking in the past year.[/b] [b]I now think that the idea of a X-factor is junk science[/b]. I don't believe that the human body can coil and uncoil - like McLean suggests. If anybody believes otherwise, please explain in anatomical terms what body part is coiling and uncoiling.[/quote]
Bolding added by me. So you read the article where McLean clearly said he did research and is publishing his findings using the data collected from 75 tour pros and 150 amateurs with the assistance of Dr. Robert Neal, and he states: "The truth is, the gap between your shoulder turn and hip turn should increase during the early part of the downswing." He clearly shows data that those 75 tour pros have an average of 17.4 degrees of this X-factor stretch as he terms it and the 150 amateurs (avg. hdcp = 17.2) have 5.9 degrees.

I've said the same general thing as McLean before on this site, here: [url="http://www.golfwrx.com/forums/index.php?s=&showtopic=115281&view=findpost&p=733633"]http://www.golfwrx.com/forums/index.php?s=...st&p=733633[/url]
even coined a term for it "dynamic X-factor" before his new research was published or known to me and you've previously disagreed with my position and stated that the hips and shoulders should turn in the downswing synchronously.
On Sept. 17, you wrote this:
[quote]I am not a proponent of restricting the backswing hip movement and definitely not a believer in the X-factor.[/quote]
The hole you've dug for yourself is getting awfully deep for you to now claim, "Points, I may have misunderstood your point of view.'"

Too late to be trying to extricate yourself from an indefensible position based on a "simple misunderstanding" when you've been spewing this "X-factor is bunk" stuff for months now on this site.
You'd earn a lot more respect from everyone here if you'd just admit your "new position you've taken in the last year" on this matter was wrong and go back to the view you had a year ago. Where is your "Biomechanical justification," "Evidentiary Support" and other fancy terms to prove that "X-factor is Junk Science?"

Remember, you started this thead with that assertion. If you are going to publicly challenge someone else's published research and call it "Junk" then prove it or admit you're wrong.

[hayam]

[quote name='christhebigsmokemoss' post='823242' date='Dec 13 2007, 04:05 PM']This might be the best way to increase power but it is also the best way to increase injury![/quote]


Exactly.
These thoughts injected to inflexible beings spells Injury, and bad overswings.

In theory I kinda agree with Mclean. I think that his theory is correct. The more flexible the golfer , the more energy he can create.. THOUGH, He did not explain there are OTHER things beside that which is responsible for substantial power for any golfers.