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Thread: Scientific Bias

  1. #1

    Scientific Bias

    When Kwon says "As I stated multiple times before, a golf downswing is a single-bout (short duration and fast) movement and it is 'mechanically impossible' to have double peaks in the thorax/pelvis angular velocity patterns", is this not a scientific BIAS??

    He's made a decision to use the proximal to distal sequence theory before vetting out other possible theories.The theory of proximal to distal sequencing is NOT the only theory out there. There can be simultaneous peaking or optimal coordination of partial momenta as proposed by Van Gheluwe and Hebbelinck. But optimal coordination theory is so ambiguous. Everyone will have different sequencing patterns and then you'd have to actually do research to figure out what's better or worse. That would set the entire industry back 10 years instead of being able to monetize now!

    The proximal to distal theory is perfect for business. It makes for a neat, tidy model and set of rules that only the scientists know. They set up perfect systems to record what they WANT to see. How else can Johnny Miller's movement be called everything under the sun but it's NOT rotation?

    Science is about making observations and then doing experiments to test your hypothesis. Business is about building models subjecting everyone to them and when they don't fit, they must be taught on how to fit the model. Business isn't about finding the truth.

    For example, Lucas can tell this story better but here goes. Anthony Kim gets 3D analyzed by the Zenolink system by Chris Welch. His pelvic rotation velocity is "too fast" at impact Welch says. Here you have an elite player with a different pattern that does not fit the model. Should a scientist try to figure out what makes this player elite? Or try to fit the elite into the model? Take a guess what happened.

    K

  2. #2
    Lloyd Higley Guest
    Could you post that paper or link from Van Gheluwe and Hebbelinck, and any others of interest....thanks

  3. #3
    Quote Originally Posted by Kelvin View Post
    When Kwon says "As I stated multiple times before, a golf downswing is a single-bout (short duration and fast) movement and it is 'mechanically impossible' to have double peaks in the thorax/pelvis angular velocity patterns", is this not a scientific BIAS??

    He's made a decision to use the proximal to distal sequence theory before vetting out other possible theories.The theory of proximal to distal sequencing is NOT the only theory out there. There can be simultaneous peaking or optimal coordination of partial momenta as proposed by Van Gheluwe and Hebbelinck. But optimal coordination theory is so ambiguous. Everyone will have different sequencing patterns and then you'd have to actually do research to figure out what's better or worse. That would set the entire industry back 10 years instead of being able to monetize now!

    The proximal to distal theory is perfect for business. It makes for a neat, tidy model and set of rules that only the scientists know. They set up perfect systems to record what they WANT to see. How else can Johnny Miller's movement be called everything under the sun but it's NOT rotation?

    Science is about making observations and then doing experiments to test your hypothesis. Business is about building models subjecting everyone to them and when they don't fit, they must be taught on how to fit the model. Business isn't about finding the truth.

    For example, Lucas can tell this story better but here goes. Anthony Kim gets 3D analyzed by the Zenolink system by Chris Welch. His pelvic rotation velocity is "too fast" at impact Welch says. Here you have an elite player with a different pattern that does not fit the model. Should a scientist try to figure out what makes this player elite? Or try to fit the elite into the model? Take a guess what happened.

    K
    I find it strange that Kwon's research/teaching interest below qualify him to be an authority on the golf swing. I mean if I want to be the fastest pole-walker, he would be my man, but golf?
    Can the man even play golf?
    Why should we even trust him?
    Its like your financial advisor selling you stuff that he does not even invest in.

    Software development for motion analysis
    Human-environment interaction
    Sport injury mechanism
    Walking pole biomechanics
    Computer simulation of the airborne movements
    Sport biomechanics

  4. #4
    Mike Duffey Guest
    Quote Originally Posted by Justin Tang View Post
    I find it strange that Kwon's research/teaching interest below qualify him to be an authority on the golf swing. I mean if I want to be the fastest pole-walker, he would be my man, but golf?
    Can the man even play golf?
    Why should we even trust him?
    Its like your financial advisor selling you stuff that he does not even invest in.
    That analogy is a little off. That example would be a golf coach telling you to make a swing change that he did not think was good.

    I think the better analogy is this: You run a cookie business, and you are making some money but not as much as you like. You hire an accountant to look at your revenue and expenditure. The accountant gives you a list of all of your expenditures, and notes that you are spending a lot of money on chocolate chips and brown sugar.

    At this point, things get interesting. The accountant states that you can save money by buying cheaper ingredients, you the baker, have to decide if the cookies will taste as good with cheaper ingredients. The accountant/biomechanist can tell you what is going on, it is up to the baker/coach to decide what changes (if any) can and should be made to improve the product.

    I expect that Dr. Kwon's Ph.D. in biomechanics and his professional interests in biomechanical analysis software and sport biomechanics makes him pretty well qualified to make a biomechanical assessment of a golf swing. I don't believe he would pretend to be a golf coach and give swing instruction based on the 3D data he collects. He has, by the way, been doing golf-specific analysis for years; the fact that he has other interests doesn't mean he doesn't know the golf swing. I hope everyone here has at least one other interest in life.

    The main reason I bring this up is to illustrate what should be the interaction between scientist and coaches. Perhaps some people here are familiar with Vladimir Zatsiorsky - while in the Soviet Union, he was one of the top couple guys in the Soviet Institute for Sport. I was lucky enough to have him as one of my two Ph.D advisors and to hear some of his stories. One thing he greatly missed after coming to the U.S. was the lack of communication and, to be honest, collegiality between exercise scientists and coaches. In his country, they worked side by side year round. In this country, well, we know that is not the case. I find it unfortunate that we do not have better interaction between the two groups.

  5. #5
    Mike,

    You can't un-ring the bell. You were rude and condescending to me and others in support of my ideas. You come to this site to namedrop and act like you're civil. "Let's just get along" doesn't work when I have screenshots of what was said and how you acted on FB.

    When I looked up your bio I see that you are an active learner of the golf swing. TPI certified, NG360, etc. So you're a beginner at teaching yet want to tell us how to teach. I can tell you now, you're barking up the wrong tree of knowledge for understanding the golf swing.

    So unless you have a sincere apology and a true desire to interact, you should find another sandbox. Or go back to the old one with Chertsock. Here you will be treated with the same respect as I got there.

    K

  6. #6
    Quote Originally Posted by Mike Duffey View Post
    That analogy is a little off. That example would be a golf coach telling you to make a swing change that he did not think was good.

    I think the better analogy is this: You run a cookie business, and you are making some money but not as much as you like. You hire an accountant to look at your revenue and expenditure. The accountant gives you a list of all of your expenditures, and notes that you are spending a lot of money on chocolate chips and brown sugar.

    At this point, things get interesting. The accountant states that you can save money by buying cheaper ingredients, you the baker, have to decide if the cookies will taste as good with cheaper ingredients. The accountant/biomechanist can tell you what is going on, it is up to the baker/coach to decide what changes (if any) can and should be made to improve the product.

    I expect that Dr. Kwon's Ph.D. in biomechanics and his professional interests in biomechanical analysis software and sport biomechanics makes him pretty well qualified to make a biomechanical assessment of a golf swing. I don't believe he would pretend to be a golf coach and give swing instruction based on the 3D data he collects. He has, by the way, been doing golf-specific analysis for years; the fact that he has other interests doesn't mean he doesn't know the golf swing. I hope everyone here has at least one other interest in life.

    The main reason I bring this up is to illustrate what should be the interaction between scientist and coaches. Perhaps some people here are familiar with Vladimir Zatsiorsky - while in the Soviet Union, he was one of the top couple guys in the Soviet Institute for Sport. I was lucky enough to have him as one of my two Ph.D advisors and to hear some of his stories. One thing he greatly missed after coming to the U.S. was the lack of communication and, to be honest, collegiality between exercise scientists and coaches. In his country, they worked side by side year round. In this country, well, we know that is not the case. I find it unfortunate that we do not have better interaction between the two groups.
    Mike,

    Something simpler for you to understand...

    Its like the cook who doesn't enjoy eating. Imagine, if you will...you take your missus out for a nice dinner.

    Steak is off, wine is flat.

    You tell the maitre d' so, who promptly informs the chef and the sommelier.
    The chef flatly tells you you are wrong, because he followed the recipe to the letter and the meat was 'farm fresh'.
    The sommelier is seething and says you are wrong because the wine came from a famous region, say Napa Valley.
    They have just discounted the possibility that a black swan event occurred.

    That Kwon has other interests are great. But it is obvious that golf is not high on that list.

    The goal of science is to disprove theory and not to find evidence that bolsters it.
    Like gold that goes through a fire, anything that is worthless will melt away.
    If you do not have a body of personal experience, then you would have less avenue to disprove your theory.

    A last word on civility...your behavior on Facebook is unbecoming of a Penn State U staff.
    No doubt Nick Chertcock's page is a closed group, yet, bear in mind that there are people (who actually used to respect you) reading your posts.
    Will you like it if someone went to https://www.facebook.com/PennStateHHD and posted in the manner you did?

    Think about it.

    Is that the legacy you want to leave behind? Not that you have a great deal. http://www.ratemyprofessors.com/Show...sp?tid=1032096

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    Leave the rowdy behavior to the (other) golf pros.

  7. #7
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    Professor Duffey! Welcome to jeffy golf!!

    Back in July, I recall some threads on Facebook discussing Kelvin's most recent articles characterizing the release. What caught my eye was your complete ignorance that in a drive/hold release, the most popular, and most stable, release style on the men's tour, the left shoulder is in internal rotation at impact and, in some cases, increases internal rotation through impact. If my memory is correct, you expressed total surprise at this and asked wouldn't internal rotation be "uncomfortable"? LOL!!! "Uncomfortable" is trying to play golf for a living and not knowing where the ball is going. What the hell kind of golf swings have you been studying? Or does the movement of the left humerus fall outside of your field of expertise?

    Looking forward to your response.


    Jeff

  8. #8
    Mike Duffey Guest
    Well, it seems that the introductions have been taken care of, so I'll skip that part.

    Justin- Regarding the Zatsiorsky reference - the story is his, not mine, so my intent to to give the source of the story. I do not mean to imply any connection to the Soviet Union or their athletic success.

    Kelvin- I am not a golf instructor in any way, and I don't believe I have ever said that I am. If I ever give golf instruction advice, it is always via discussion with an actual golf instructor. I will tell him/her what I have seen in 3D and let the instructor choose whether or not to work that information into the teaching program. Any disagreement that you and I have had is not related to your teaching ability (which seems quite good from others' comments), it would only be on matters related to analysis of movement, which is my field. If you felt that I was belittling your teaching ability, I do apologize and I certainly wouldn't go to anyone's professional web site or facebook page and post public insults (as brought up above).

    I came here with the intent to try to have an objective conversation about things related to biomechanics. I promise that I will listen to what is written here and try to limit my responses only to material that falls within my professional knowledge base.

    Which gets us to Jeff's question: Why the "uncomfortable" comment and why I was surprised by the internal rotation suggestion.
    There are two parts to this - First, I will say up front that I assume the club, and therefore the left hand, are rotating counterclockwise (supinating) through impact. This means that the upper arm and the forearm would be rotating in opposite directions. I haven't seen this combination of motions in other sports, though I freely admit that I haven't looked at arm motion in every sport. Most of my upper body data collection has been related to golf. I will say that this combination of motions would likely act to slow the rate of supination, so it would (if it happened) probably help reduce rate of rate of closure - which I believe is what you are saying it does.
    Second, the upper arm data that I have seen shows that the upper arm is most internally rotated around near the top of the backswing and tends externally rotate well through impact. So option one is that the arm is substantially internally rotated at TOB and then continues to internally rotate. You would quickly run out of the available range of motion - which would be uncomfortable. The other option is that the upper arm starts to externally rotate briefly and then reverses direction. This would give more available ROM at the shoulder, however, this motion (in isolation) would act to open the club face, so you would then have to substantially and rapidly supinate the wrist/forearm. I believe this combination of motions at the elbow would be uncomfortable.





    Regarding your question about what kind of swings I have been studying - the vast majority of the swing data that I have collected is on the students in the PGM program here. They are basically 18-23 year old men and women who are playing at a 0-10 handicap. Relative to the golfing population, I consider them to be good but not great/competitive elite golfers. I expect that the instructors here would like some of their swings quite a bit and think that some need a fair amount of work, which I feel makes them a nice population to work with.

    We have a current database with a couple thousand swings in it and I will say that I have not looked at humerus velocity at impact in all of them. I might have time in the next couple weeks to look through, however, if someone has some 3D data showing IR of the humerus through impact, posting it would certainly speed along the discussion. Before I commit a bunch of time to this, I'd like to make sure that we are all saying the same thing.

  9. #9
    Lloyd Higley Guest
    My 2 cents. i think it was very admirable for Mike to come here and have a discussion. I understand the bs that has gone on between both sides of this. I for one would like to see a better respect for each others opinions. i welcome Mike and hope we all can try to tone down our rhetoric and just discuss. Mike has a lot to offer and so do you Kelvin even our host Jeff does and nobody ruffles more feathers than him...geeez. Lucas, Lifter, Justin, Art and the rest can make this discussion a great one or we can make it a crap one...lets learn from one another and put the egos, a little aside....jmho

  10. #10
    nice post coach,
    and welcome mike

    just my personal experience here cause i've been altering my left shoulder moves to stabilise my ROC. we can start another thread about this...

    (for mike, i'm a +1 - +2 hcp working my way up french rankings, been working with kel for a year and half or so, added a good 20y to driver and about an iron and a half, while switching to a drive hold release, or almost there..)

    still loads of work on the lower body but...

    first is from february and you can see clearly my left shoulder going ER and adducting during impact, increasing my ROC...and left wrist has to stop supinate and even pronate to maintain a decent ROC, so moves are going in reverse with a lot of rolling...i'm not flipping in it cause i have created decent lag late enough but it's a close call
    this was feelling really uncomfortable having to reverse the moves to save shots



    on the second this month i was taking the left elbow flexion cluster to the extreme...granted
    left elbow flexion cluster info : Lag Release Micro Move #6 and #7 – Left Bicep Contraction and Left Arm slightly flexed (bent)
    here : http://www.aroundhawaii.com/lifestyl...e-release.html

    but you can see a much different left shoulder behaviour and a better release thanks to that
    it was not that hard of a change i just had to understand what the follow through had to look like and which way i could deliver the club to the finish, once it's clear the position of left shoulder IR is not really uncomfortable per se

  11. #11
    Lloyd Higley Guest
    Nice change Robin with release, work on lower body is definitely next step

  12. #12
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    Professor Duffey-

    I think your second post and Robin's post illustrate exactly how sports biomechanics should work.

    1. An expert in qualitative analysis, Kelvin, identifies anatomical movements common to elite ballstrikers.

    2. He concludes, as you did, that the combination of left shoulder internal rotation through impact plus early left forearm supination will produce a more stable release: one where there is a slower rate of closure through impact.

    3. He tests his hypothesis with a student who successfully makes the recommended movement changes and experiences improved ball striking. Up to this point, the process has relied solely on high-speed video and the coach's knowledge of anatomy and the golf swing.

    4. The instructor/qualitative analyst presents these findings to a golf biomechanist. Not being an expert in golf instruction or elite golf swings, this is a novel concept to the biomechanist. It piques his interest.

    5. Using the information provided by the instructor/qualitative analyst, the golf biomechanist determines what segments to study and what motions to analyze.

    6. To determine "baseline" information, he goes to his data base of existing swings (a couple thousand) to quantify the motions of interest (e.g. lead humerus rotation, lead forearm rotation, etc.).

    7. With the baseline information established, the biomechanist can quantify the differences among players and, perhaps working with the instructor/qualitative analyst, group players into categories based on similar combinations of movements (e.g., drive/holder, roller, etc.).

    8. He can also seek out specific players to measure, such as the student of interest, or obtain existing data on the elite players the instructor/qualitative analyst used as models.

    9. From this, a quantitative model of the different release styles can be developed.



    Sound more or less correct?




    Jeff

  13. #13
    Mike Duffey Guest
    Certainly more than less.

    One thing on step 2: I would not use the word stable there - though you have clarified what you mean, so I see where you are going. I do agree that I would expect a slower ROC as described, but I wouldn't assume more stability. Slower does not always mean more stable: think of trying to ride a bike very slowly, it actually becomes less stable. So at times, restricting movement and/or movement velocity might not lead to better stability (in this case, I'd say stable means improved ability to repeatedly perform the same movement the same way). So while I would not assume that slower ROC automatically makes things more stable, I do agree it is possible, and I do think it would be worth a good look as you describe.

  14. #14
    Mike Duffey Guest
    Sorry, I hit submit a bit early.
    I also really like steps 8 and 9.

  15. #15
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    Professor Duffey-

    Excellent!

    So let's return to the Johnny Miller thread on Facebook.


    1. An expert in qualitative analysis, Kelvin, identifies anatomical movements common to elite ballstrikers.

    2. He concludes that a combination of lower body movements he calls the "second fire" will not only increase clubhead speed, but contribute to a more stable release.

    3. He tests his hypothesis with many students who successfully make the recommended movement changes and experience improved ball striking. Up to this point, the process has relied solely on high-speed video and Kelvin's knowledge of anatomy and the golf swing.

    4. Kelvin presents these findings to a group of golf biomechanists. Not being experts in golf instruction or elite golf swings, this is a novel concept to the biomechanists. It piques their interest. Or do they just dismiss it?


    It seems to me we are at this point in the process! Ball's in your court!




    Jeff

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