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Kelvin Miyahira
August 27th, 2013, 08:52 AM
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

Lloyd Higley
August 27th, 2013, 11:14 AM
Could you post that paper or link from Van Gheluwe and Hebbelinck, and any others of interest....thanks

Justin Tang
August 28th, 2013, 01:27 AM
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

Mike Duffey
August 29th, 2013, 04:58 PM
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.

Kelvin Miyahira
August 29th, 2013, 06:09 PM
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

Justin Tang
August 29th, 2013, 06:32 PM
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/ShowRatings.jsp?tid=1032096

1840

1841

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

Jeff Martin
August 29th, 2013, 07:09 PM
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

Mike Duffey
August 29th, 2013, 10:38 PM
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.

Lloyd Higley
August 29th, 2013, 10:54 PM
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

Robin Cocq
August 30th, 2013, 03:31 AM
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


http://youtu.be/cmAfJHYfiUk

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/lifestyle/health_and_fitness/2011-12-pga-tour-clubhead-lag-part-3-the-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

http://youtu.be/nmCUpO8rS4M

Lloyd Higley
August 30th, 2013, 07:44 AM
Nice change Robin with release, work on lower body is definitely next step

Jeff Martin
August 30th, 2013, 10:57 AM
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

Mike Duffey
August 30th, 2013, 12:18 PM
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.

Mike Duffey
August 30th, 2013, 12:19 PM
Sorry, I hit submit a bit early.
I also really like steps 8 and 9.

Jeff Martin
August 30th, 2013, 12:42 PM
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

Jeff Martin
August 30th, 2013, 12:50 PM
Memo to: Prof. Duffey

Subject: TO DO LIST - SECOND FIRE STUDY

1. Using the information provided by Kelvin, determine what segments to study and what motions to analyze.

2. To determine "baseline" information, process data base of existing swings (a couple thousand) to quantify the motions of interest (e.g. lead hip and knee extension, hip sway, pelvic thrust, etc.).

3. With the baseline information established, quantify the differences among players and, perhaps working with Kelvin, group players into categories based on similar combinations of movements (e.g., second-fire, staller, etc.).

4. Obtain existing data on the elite players Kelvin used as models; if possible, arrange to test one or more of Kelvin's students.

5. Develop a quantitative model of the different lower body movement classifications.



Sound more or less correct?




Jeff

Robin Cocq
August 30th, 2013, 02:11 PM
mike about the stability of the release you're right, low Roc doesn't mean consistently low roc, and if that's not the case indeed it's going to cause problems...

around this topic, flip rolling release is the one we tend to flee from...

rolling release is a high ROC release but it has its advantage, it is repeatable
and if the changes are too drastic sometimes, kelvin also prefers teaching a rolling release first, in order to then move on to the drive holding release...
mickelson is a good example of a rolling release, his ROC is high, but it's consistently high, which means if he keeps his rythm in check he's perfectly fine and can play wonderfully


to this date drive holding is pretty much getting best of both worlds if i can venture on that road,
cause that right wrist flexion rate is really slow ensuring consistency with angle of attack, loft, and also helping the ROC,
and the holding part (left forearm supination and flexion with left shoulder IR is decreasing the ROC...

it's very helpfull to get a ONE WAY miss we all try to achieve

Mike Duffey
August 30th, 2013, 09:08 PM
Memo to: Prof. Duffey

Subject: TO DO LIST - SECOND FIRE STUDY
1. Using the information provided by Kelvin, determine what segments to study and what motions to analyze.
2. To determine "baseline" information, process data base of existing swings (a couple thousand) to quantify the motions of interest (e.g. lead hip and knee extension, hip sway, pelvic thrust, etc.).
3. With the baseline information established, quantify the differences among players and, perhaps working with Kelvin, group players into categories based on similar combinations of movements (e.g., second-fire, staller, etc.).
4. Obtain existing data on the elite players Kelvin used as models; if possible, arrange to test one or more of Kelvin's students.
5. Develop a quantitative model of the different lower body movement classifications.

Sound more or less correct?

Jeff

Jeff, I have fallen behind by a post, so I'm going out of order. This sounds generally good. Kelvin was invited to bring or send some people to Dr. Kwon's lab in Texas a couple of times, and I believe Phil Cheetham also invited him to send some folks to his place (probably Arizona?) I don't know that Kelvin responded, but I do realize that might be geographically difficult. I'd expect those offers are still open and it sounds like you, at least, are interested? Phil has more data on elite level players than I do, so he might have a better data set for that level of comparison. I don't know about Dr. Kwon.

Mike Duffey
August 30th, 2013, 09:29 PM
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

Given that was not just a hypothetical, I'll try to address what happened, clearly it was not the best of objective and productive discussions. I think there were two primary issues:
1. There are evidently some (substantial?) personality clashes, possibly with some long and unpleasant history. Those are what they are, regrettably, and probably don't need further discussion.
2. There were a couple of big issues with the terminology being used and the data that was being used to support it.
About the terminology-
If I remember right (and those threads are hundreds of posts long now, so I apologize if I miss something) the terminology issues were "second fire" and "rotation". Hopefully we can agree that we can't see muscles firing on 2D video or 3D analysis. In either technology we can look at movement and hypothesize that there was a secondary increase in muscle activation, but we can not confirm its existence. EMG would be the appropriate technology for assessing that.
The biomechanics field has spent decades using both 2D and 3D technology and determining what movements can and can not be measured with reasonable accuracy with either system. While it might not be helpful (and maybe not well explained), it is not surprising to get substantial resistance when someone makes strong claims about seeing a rotation on 2D video that the people who have spent their lives in the field have come to understand that it is not accurately measurable given the provided orientation of the video camera.
Also, it appears that Kelvin either defines rotation differently than basically everyone in physics, engineering, and biomechanics, or he did not understand what we being said. I do not mean this as a potential insult; Kelvin clearly disagreed with what was being written, but I didn't catch the source of the disagreement.

About the data collection-
As I am sure you read, there is not published evidence that markerless, video-based motion capture is a viable and accurate technology at this time. It appeared that some of the data, perhaps all of the data, being provided as support of a second hip velocity increase, was coming from that type of system. For better or worse, the standard in biomechanics at least (I believe in many other fields) is that validation data should be presented before simply announcing a new type of system is accurate.

All of the above is a discussion of the past. I think what you are saying is that the science-type folks (and I am probably included in that) should have been more receptive to the discussion. I would likely agree. I would absolutely agree that I wish there had been better dialogue and a more fruitful end to the conversation.

As a side note, Tapio has begun posting some of his data and some of the validation questions are now (at least I hopefully believe ) are being addressed. That will almost certainly go better with him being able to discuss his own methods rather than a 3rd party trying to do it. Kelvin was certainly in an unenviable position.

Does that address what you had in mind?

Kelvin Miyahira
August 31st, 2013, 12:46 AM
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.

Why bother? We study elite golf swings of PGA tour players. What would you expect to find with amateurs? What not to do?

As to the 2nd paragraph, could you explain further how you would measure IR of humerus?

Mike Duffey
August 31st, 2013, 08:51 AM
Kelvin, in any sport or movement, it is good to know how things are done in an ideal case and how things are done by others. For our students, it is good for them to know what they are likely to see in 10-20 handicap players, how things change in the 0-10 handicap players, and sure, what the plus handicap players do.

There are two realities: one is that it helps these guys know what they are doing. The other is that most golf instruction involves 5-25 handicap players who will never, ever approach elite status.
So why bother? Because we deal with the reality of who these players are and who they will teach. There are some other reasons, but those are the big ones.

We would calculate orientation of the humerus relative to the torso. Internal rotation would be clockwise [Edit] rotation of the (left) humerus along the long axis of the bone. I'm not sure that really answers your question, is there something more you are asking?

Kelvin Miyahira
August 31st, 2013, 09:57 AM
Oh so you teach with lower quality models and data? I'm not interested in that at all. And there you go again condescending now to players "that will never approach elite status." Let's just disagree that your data is NOT useful in my world.

This is critical because I don't think the stream flows up the mountain. How do you take knowledge gained from amateurs and make tour pros better? Did the Russian coach take movies of bad shot put guys or the best? How do you get a player from a 0 handicap to a +5 with that same knowledge?

As to the IR question, I only asked since you made an error in your post about measuring "humerus velocity."

Jeff Martin
August 31st, 2013, 01:06 PM
Jeff, I have fallen behind by a post, so I'm going out of order. This sounds generally good. Kelvin was invited to bring or send some people to Dr. Kwon's lab in Texas a couple of times, and I believe Phil Cheetham also invited him to send some folks to his place (probably Arizona?) I don't know that Kelvin responded, but I do realize that might be geographically difficult. I'd expect those offers are still open and it sounds like you, at least, are interested? Phil has more data on elite level players than I do, so he might have a better data set for that level of comparison. I don't know about Dr. Kwon.



With a data base of elite players, a visit isn't really necessary to conduct an analysis. At this point, if your group has a genuine interest in understanding the "second fire", or any other element of an elite swing, conduct the appropriate analysis using the existing data, then let us know what you find. Of course, we'll provide any additional guidance that is required.



Jeff

Mike Duffey
August 31st, 2013, 10:11 PM
Oh so you teach with lower quality models and data? I'm not interested in that at all. And there you go again condescending now to players "that will never approach elite status." Let's just disagree that your data is NOT useful in my world.

This is critical because I don't think the stream flows up the mountain. How do you take knowledge gained from amateurs and make tour pros better? Did the Russian coach take movies of bad shot put guys or the best? How do you get a player from a 0 handicap to a +5 with that same knowledge?

As to the IR question, I only asked since you made an error in your post about measuring "humerus velocity."

Kelvin,
Would you agree that to improve someone's swing, you need to know both what that person is doing now and the target of where you would like to get them? You seem to use 2D video (at least) to do this, right? We use 2D video and 3D analysis as our choice of tools.

Why we create a database from this? Of course we are not trying to teach 5 handicap players how to be 5 handicap players (or 10 or 15). It gives us the opportunity to tell our students what they are likely to see as they begin their instruction careers. Since, by definition, our students are young and inexperienced (all beginning instructors are), it will help them to have a preview of what they are getting into.

About the condescending comment, what percentage of golf players will reach the elite status?

And sorry about the counterclockwise - thanks for catching it.

Mike Duffey
August 31st, 2013, 10:42 PM
With a data base of elite players, a visit isn't really necessary to conduct an analysis. At this point, if your group has a genuine interest in understanding the "second fire", or any other element of an elite swing, conduct the appropriate analysis using the existing data, then let us know what you find. Of course, we'll provide any additional guidance that is required.

Jeff

Jeff,
Here's the thing: Phil is saying his data does not show evidence for a "second fire" in the golf swing. So far, mine doesn't either, but I'll keep looking (though it sounds like Kelvin is not interested in my data, so perhaps it is not worth the time).

What is needed is for someone who has it to "show it" on the record - meaning for that person to be willing to do a 3D data collection.

Kelvin Miyahira
September 1st, 2013, 08:55 AM
Mike,

At the risk of sounding arrogant myself, which I am not. Here's my take on where you're at. You are where I was 25 years ago. I started the search by seeking the top instructors in the field, Lead, Haney, Gilchrist, Ballard, Toski, Puterbaugh and more. I found that each had a piece of the pie but no one had the whole pie nor did anyone have real research to back up what they taught and why. You may be an expert at 3D but you don't know much about the very sport you have chosen to dive into. How you can teach other teachers how and what to teach is beyond me. You are still learning a lot yourself and from sources with questionable biases. Yet you don't know enough about them to even make that assessment therefore you accept with blind faith what you learn from these "experts." With knowledge gained and added marketability, you can have a good business going. Good for you. Happy for you. But you have not arrived at the truth yet.

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCwQFjAA&url=http%3A%2F%2Fwww.iaaf.org%2Fdownload%2Fdownload%3Ffilename%3Dccbfb687-f00d-4de1-9750-e12b45decbf0.pdf%26urlSlug%3D10-biomechanics-report-wc-daegu-2011-hammer&ei=XykjUuG2EaPgiAKwoYCQCw&usg=AFQjCNGjdRcXcfY5RKCB9HbpZslEChlfVQ&sig2=TF_tOlbnS7HDo8rkJAlPLg

I leave you with this study of the hammer throw. They measured the velocity increases in each "turn" among other variables important to their sport. How long will it take biomechanists to tell them it IS NOT a turn?

I don't feel there is anything to be gained by continued discussions. I'm out.

Jeff Martin
September 1st, 2013, 11:56 AM
Jeff,
Here's the thing: Phil is saying his data does not show evidence for a "second fire" in the golf swing. So far, mine doesn't either, but I'll keep looking (though it sounds like Kelvin is not interested in my data, so perhaps it is not worth the time).

What is needed is for someone who has it to "show it" on the record - meaning for that person to be willing to do a 3D data collection.


I think you are mistaken. Phil is saying on Facebook that there is a second fire (even getting a little testy about it), which is a power source, that involves lead hip and leg extension as one of the components. He says biomechanists know all about it.


1847


Chris Como told me the same thing:

1848




In addition to lead hip and leg extension, there are other segments and movements of the second fire that Kelvin laid out in the "Johnny Miller video":



http://youtu.be/zGC68eSLcmw



Kel lays out the five main causes of stalling here:



http://youtu.be/gA2iIxUai8M



Your project is simple. Get the 6DOF data from players like JB, Sadlowski, Woodland, Bubba, Dustin, pre-2013 Keegan, Tommy Gainey, etc. and compare it to players that stall: sliders like Luke Donald and Grant Waite, jump-stallers like Lexi Thompson and Brian Gay, left leg bracers like Brooke Pancake and Katie Fucher, etc. That should give a basis for quantitative models of different lower body movement combinations. Then students can come in and be compared to the different models and be shown what quantitative changes need to happen to go from stalling to a second fire.




Jeff

Jeff Martin
September 1st, 2013, 12:05 PM
This is the graph Phil was referring to that shows lead hip and leg extension, both firing late in the downswing, after the first fire of the spine, all the way into impact.


1849




Jeff

Mike Duffey
September 1st, 2013, 03:58 PM
Jeff,
My understanding of the conversation, which was quite a long one, is that Kelvin's "second fire" refers to the pelvis continuing to rotate, in fact that it speeds up a second time during the downswing. The video you posted is perfect as Kelvin carefully explains the difference between what he is calling a rotation and what we call hip extension. Kelvin carefully and thoroughly does this through just over the first minute of the video.
So, my understanding of the conversation on FB and the video here is that Kelvin considers a "second fire" to be seen as a secondary increase in pelvis rotation. If that is still what Kelvin calls a second fire, I would argue against the likelihood of it happening in a good swing.
If that is no longer his definition of a second fire, and he means that is includes hip extension and pelvis posterior tilt (as seen in JM's swing), I might ask why that is called a "second fire", but I wouldn't argue against that being a viable motion in a good swing.

Perhaps Kelvin can make sure we all know specifically what the second fire means and how it got the name?

Mike Duffey
September 1st, 2013, 04:04 PM
Your project is simple. Get the 6DOF data from players like JB, Sadlowski, Woodland, Bubba, Dustin, pre-2013 Keegan, Tommy Gainey, etc. and compare it to players that stall: sliders like Luke Donald and Grant Waite, jump-stallers like Lexi Thompson and Brian Gay, left leg bracers like Brooke Pancake and Katie Fucher, etc. That should give a basis for quantitative models of different lower body movement combinations. Then students can come in and be compared to the different models and be shown what quantitative changes need to happen to go from stalling to a second fire.

Jeff

Ok, I'll give you full marks for calling that project simple. Not doubt it is simple, but it is far from easy. I think it is somewhere between absurdly difficult and impossible, but since you brought it up, perhaps you have much better contact with those players than I do. Are willing to help? Please contact them and get them to go into my lab (or any other mentioned previously) for 3D testing. I agree that would be an outstanding contribution to the fields of golf instruction and analysis.

Jeff Martin
September 1st, 2013, 04:09 PM
I think we all know what the second fire is. The first fire is by the spine engine and initiates the downswing, and the second fire are movements of the legs and hips which add power through shear forces. We know the second fire doesn't show up in the kinetic sequence charts produced by AMM/TPI. That's why you have to look elsewhere and Kel has told you where to look.


Jeff

Mike Duffey
September 1st, 2013, 04:23 PM
Ok, so if you are confirming that the second fire constitutes motion other than pure (about the pelvis vertical axis) pelvis rotation - for example hip extension and/or pelvis posterior tilt, then I am happy to agree with you and I can tell you that you have cleared up what 300+ posts in two threads on FB did not clear up. This seems like great progress.

You are correct that those motions are not presented in the downswing kinematic sequence graph, which is on page 5 of the AMM biomechanics report. They are on page 11. That information is on pages 9 and 10 in our report and is also on page 10 of the GBD report.

Jeff Martin
September 1st, 2013, 08:16 PM
Ok, so if you are confirming that the second fire constitutes motion other than pure (about the pelvis vertical axis) pelvis rotation - for example hip extension and/or pelvis posterior tilt, then I am happy to agree with you and I can tell you that you have cleared up what 300+ posts in two threads on FB did not clear up. This seems like great progress.

You are correct that those motions are not presented in the downswing kinematic sequence graph, which is on page 5 of the AMM biomechanics report. They are on page 11. That information is on pages 9 and 10 in our report and is also on page 10 of the GBD report.


Well, you have that shit-for-brains Nick Chertock to thank for that. Kel and Phil Cheetham had pretty much agreed on this, or were damned close, when Kel was banned.



Jeff

Jeff Martin
September 1st, 2013, 08:21 PM
Ok, I'll give you full marks for calling that project simple. Not doubt it is simple, but it is far from easy. I think it is somewhere between absurdly difficult and impossible, but since you brought it up, perhaps you have much better contact with those players than I do. Are willing to help? Please contact them and get them to go into my lab (or any other mentioned previously) for 3D testing. I agree that would be an outstanding contribution to the fields of golf instruction and analysis.


What am I missing? I thought the data was already collected by TPI for a couple hundred tour players. Send us the list and we will give you a few representative players in each category.




Jeff

Mike Duffey
September 1st, 2013, 09:41 PM
Jeff,
I'd be surprised if it were a couple hundred tour players, but regardless - that is their data, not mine. I can't offer it. But remember, Phil offered to test the subject(s) of your/Kelvin's choice and discuss it and his other data with you. It seems that offer is on the table for you to accept.

Jeff Martin
September 2nd, 2013, 10:56 AM
It was generous of you, Phil Cheetham and Dr. Kwon to offer to host visits to your labs, but, speaking for myself, I have little to gain from one. I know what the second fire is, as well as most of the 130 micro moves seen in elite golf swings. What would interest me is a thorough quantitative analysis of how elite players differ in these movements from non-elites. Kel has provided the roadmap, it is up to the biomechanists to get it done.

As an aside, it is very hard for me to get my head around the fact that golf biomechanists as a group aren't first and foremost studying the swings of the elite. It is as if Cheetham was the only music researcher who had access to the works of Mozart, Beethoven, etc. I strongly suggest you guys work out some kind of data sharing arrangement of elite swings because, as Kel said, all you have in your database of a couple thousand amateur swings is what NOT to do.

Good luck with your research!


Jeff

Mike Duffey
September 3rd, 2013, 10:13 AM
Jeff,
We have some guys that can carry the ball 285 down the middle. I'll take that shot all day. More importantly, it sounds like you think the purpose for us collecting swing data is only to teach the bad of what we see, or as you put it, what NOT to do.

One of the things we can do is look at good swings versus not as good and look for sources of error for an individual golfer. For example, let's say a person's noticeable swing flaw is a slice that occurs when the face is still square to target but the golfer is swinging outside in. We can go back and start looking for the source of error. Did things start changing in the backwsing? In the downswing? You could think of it as a diagnostic tool.

Jeff Martin
September 4th, 2013, 11:36 AM
Jeff,
We have some guys that can carry the ball 285 down the middle. I'll take that shot all day. More importantly, it sounds like you think the purpose for us collecting swing data is only to teach the bad of what we see, or as you put it, what NOT to do.


No, I know what the purpose is for collecting the data, the problem is your data doesn't have much value. Sure, there are likely some good swings in there, but you are in no position to know what elements are good and what elements aren't because you haven't studied elite swings. You're flying blind.



One of the things we can do is look at good swings versus not as good and look for sources of error for an individual golfer. For example, let's say a person's noticeable swing flaw is a slice that occurs when the face is still square to target but the golfer is swinging outside in. We can go back and start looking for the source of error. Did things start changing in the backwsing? In the downswing? You could think of it as a diagnostic tool.


Sort of like high-speed video? Except video is lot cheaper, easier to use, and presents a lot more qualitative information. Without the data on elite swings, that I guess only Phil has, I'm not sure what good it does to gather quantitative information, except keep you busy.



Jeff

Jeff Martin
September 4th, 2013, 07:08 PM
Ok, so if you are confirming that the second fire constitutes motion other than pure (about the pelvis vertical axis) pelvis rotation - for example hip extension and/or pelvis posterior tilt, then I am happy to agree with you and I can tell you that you have cleared up what 300+ posts in two threads on FB did not clear up. This seems like great progress.

You are correct that those motions are not presented in the downswing kinematic sequence graph, which is on page 5 of the AMM biomechanics report. They are on page 11. That information is on pages 9 and 10 in our report and is also on page 10 of the GBD report.


Just so you know, Kelvin didn't come up with this "second fire" theory on the fly "midstream" during the Facebook debate. He first described it in this article published in December 2008.


http://www.aroundhawaii.com/lifestyle/health_and_fitness/2008-12-tiger-and-sadlowski-swing-emergence-of-a-new-more-powerful-swing.html



Jeff

Jeff Martin
May 19th, 2014, 11:54 AM
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/ShowRatings.jsp?tid=1032096

1840

1841

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



hmmmm... Still room for improvement, it seems...


2779



Jeff

Jeff Martin
May 19th, 2014, 12:03 PM
Ok, so if you are confirming that the second fire constitutes motion other than pure (about the pelvis vertical axis) pelvis rotation - for example hip extension and/or pelvis posterior tilt, then I am happy to agree with you and I can tell you that you have cleared up what 300+ posts in two threads on FB did not clear up. This seems like great progress.

You are correct that those motions are not presented in the downswing kinematic sequence graph, which is on page 5 of the AMM biomechanics report. They are on page 11. That information is on pages 9 and 10 in our report and is also on page 10 of the GBD report.


Professor Duffey-

Now that I have access to the AMM/TPI biomechanics report, I see you were fibbing. Here is a screen cap of page 11 for Pro1:


2782


Those "motions" are not "presented" at all, simply the overall range of motion. I don't like being bullshitted. Why should I believe anything you say at this point? Why should I let you continue to post here?




Jeff

jaja
May 20th, 2014, 05:31 AM
Professor Duffey-

Now that I have access to the AMM/TPI biomechanics report, I see you were fibbing. Here is a screen cap of page 11 for Pro1:


2782


Those "motions" are not "presented" at all, simply the overall range of motion. I don't like being bullshitted. Why should I believe anything you say at this point? Why should I let you continue to post here?




Jeff

Just read through this thread. My impression? That Duffy is disingenuous parasite.

Mike Duffey
June 4th, 2014, 10:35 PM
Professor Duffey-

Now that I have access to the AMM/TPI biomechanics report, I see you were fibbing. Here is a screen cap of page 11 for Pro1:


2782


Those "motions" are not "presented" at all, simply the overall range of motion. I don't like being bullshitted. Why should I believe anything you say at this point? Why should I let you continue to post here?




Jeff

Jeff, you know as well as I do, and probably even better that you can pull up a graph of pelvis position or pelvis velocity in AMM. You have shown considerable you have shown skill in pulling up lots of graphs in AMM. The basic data is on those pages, you can easily show us the graph if you would like.

Here are the pelvis position and velocity pages in our report.30073008

Jeff Martin
June 11th, 2014, 08:50 PM
Jeff, you know as well as I do, and probably even better that you can pull up a graph of pelvis position or pelvis velocity in AMM. You have shown considerable you have shown skill in pulling up lots of graphs in AMM. The basic data is on those pages, you can easily show us the graph if you would like.

Professor Duffey-

I didn't notice this post until tonight. What complete bullshit. This is what you posted:



You are correct that those motions are not presented in the downswing kinematic sequence graph, which is on page 5 of the AMM biomechanics report. They are on page 11. That information is on pages 9 and 10 in our report and is also on page 10 of the GBD report.


That is no less than a bald faced lie. Don't try to change the subject to what graphs can be pulled up from the AMM data base. You said the "motion" information was on page 11. YOU WERE LYING. Is this what life in academia does to a person's intellectual honesty and self-respect? Or were you always like this?





Jeff

Mike Duffey
June 12th, 2014, 04:12 PM
Jeff,
Did you notice that I posted the pages from our report that are those motions? AMM presents data at those positions, you never said you wanted the full graph or nothing, I am sorry I didn't know something that you didn't write. We have said multiple times that there is simply too much data to present in a standard report to everyone. I understand that you think some things are important, but you know exactly how to get that data.

There was no attempt to lie and you know it. Jeff, I don't know what your issue is, but I don't know why you can't act civilly. Do you have some kind of problem with me that you would like to discuss out in the open?

Jeff Martin
June 12th, 2014, 05:41 PM
Professor Duffey-

Do you have a problem with the truth? I don't like being bullshitted and I count your most recent reply as the third time you've tried to bullshit me on this topic. If you can't be truthful, you deserve the treatment you get. It's nothing personal, you're just an unrepentant liar.




Jeff

Mike Duffey
June 12th, 2014, 10:36 PM
I literally posted the stuff you asked for from our report. As far as the AMM report, it is like a child who asks for apples and is told the apples are on the table. There are only three apples and the child complains that he wanted 50.

They include the data you asked for, but at select positions. Apparently you wanted more, but you know how to get more. I didn't lie or bullshit you. Just because you feel there should be more available doesn't make me a liar, but perhaps it would be time for you to mention that you think there should be more. Insulting me doesn't help you or the situation, especially since I have absolutely no control over the AMM report and you know that.

Perhaps you like our report better because it provides the entire graph. Do you? You forgot to mention that part.

Jeff Martin
June 12th, 2014, 10:39 PM
That's four times you've tried to bullshit me. You lied about what was in the AMM report. What's in your report is irrelevant.



Jeff

Mike Duffey
June 12th, 2014, 10:46 PM
Please explain to me how them presenting the data you want, but only at a select positions, is bullshitting you. The fact that you want more doesn't mean they don't present it.

John Thomas
June 13th, 2014, 04:17 AM
Duffey , why do your students basically give you a bad rating ?

Jeff Martin
June 13th, 2014, 08:17 AM
Please explain to me how them presenting the data you want, but only at a select positions, is bullshitting you. The fact that you want more doesn't mean they don't present it.


I already explained in post #41. Stop bullshitting.




Jeff

Mike Duffey
June 13th, 2014, 10:08 AM
Those "motions" are not "presented" at all, simply the overall range of motion. I don't like being bullshitted. Why should I believe anything you say at this point?
Jeff

Jeff, read your own words. Range of motion is in fact, a presentation of the motion. Is it complete, no. If you are going to split that hair and say that range of motion is completely inadequate and the difference in 'graph of the motion of the entire swing' and 'range of motion' is so important that you will repeatedly call someone a liar/bullshitter for mixing the two, then please show me your post that asked for complete motion throughout the swing.

I'll save you the trouble - you didn't, you just asked for motion. Why am I saving you the trouble? Because unlike you, I don't delight in wasting other people's time.

I didn't bullshit you, I showed you data. Exactly the data you asked for from my own report. Apparently AMM doesn't give you what you want in their standard report, but you know exactly how to get it. You then turned around and tried to bullshit me and everyone who might be reading this. Why do it? Why grasp at straws to make personal attacks and insults instead of discussing the golf swing?

Jeff Martin
June 13th, 2014, 01:59 PM
Jeff, read your own words. Range of motion is in fact, a presentation of the motion. Is it complete, no. If you are going to split that hair and say that range of motion is completely inadequate and the difference in 'graph of the motion of the entire swing' and 'range of motion' is so important that you will repeatedly call someone a liar/bullshitter for mixing the two, then please show me your post that asked for complete motion throughout the swing.

I'll save you the trouble - you didn't, you just asked for motion. Why am I saving you the trouble? Because unlike you, I don't delight in wasting other people's time.

I didn't bullshit you, I showed you data. Exactly the data you asked for from my own report. Apparently AMM doesn't give you what you want in their standard report, but you know exactly how to get it. You then turned around and tried to bullshit me and everyone who might be reading this. Why do it? Why grasp at straws to make personal attacks and insults instead of discussing the golf swing?


I'd be delighted. Here is the post I think initiated this exchange:


I think we all know what the second fire is. The first fire is by the spine engine and initiates the downswing, and the second fire are movements of the legs and hips which add power through shear forces. We know the second fire doesn't show up in the kinetic sequence charts produced by AMM/TPI. That's why you have to look elsewhere and Kel has told you where to look.



Here is your response:


Ok, so if you are confirming that the second fire constitutes motion other than pure (about the pelvis vertical axis) pelvis rotation - for example hip extension and/or pelvis posterior tilt, then I am happy to agree with you and I can tell you that you have cleared up what 300+ posts in two threads on FB did not clear up. This seems like great progress.

You are correct that those motions are not presented in the downswing kinematic sequence graph, which is on page 5 of the AMM biomechanics report. They are on page 11. That information is on pages 9 and 10 in our report and is also on page 10 of the GBD report.



Ok, let's engage in a hypothetical. Let's say you ask a student to "present" the "movements of the legs and hips" that comprise the "second fire".

Let's say the student produces this:

3044
3045


It is not hard to envision the field day you would have heaping scorn and ridicule on the poor dolt because that information tells you next to nothing about the movements of the hips and knees during the second fire. Now, let's imagine the student responds by saying: "Professor, you are just 'hair splitting', I gave you what you asked for". Presumably, at that point, you dismiss the clueless student from your classroom.

So you then ask a second student to perform the assigned task, who comes back and presents the following:

3046
3048


At this point, I assume you would explode and demand: "Where on these two pages is there ANY information describing the movements of the hips and knees during the second fire? I didn't ask for pelvis data. This is bullshit!!!"

What if that student responds by saying: "It's not bullshit, Professor. It is exactly the data you asked for. Why are you grasping at straws and insulting me?" At that point, I assume you have a stroke.

Suffice it say that it is obvious who the bullshitter and the bullshittee are in this discussion, as well as who the colossal time waster is.





Jeff

Mike Duffey
June 13th, 2014, 03:35 PM
Jeff,

I have probably asked you a half dozen times what the second fire is. Originally it was understood to be a second acceleration of the pelvis axial rotation. You have never actually answered the question. the closest you have come is this:


I think we all know what the second fire is. The first fire is by the spine engine and initiates the downswing, and the second fire are movements of the legs and hips which add power through shear forces. We know the second fire doesn't show up in the kinetic sequence charts produced by AMM/TPI. That's why you have to look elsewhere and Kel has told you where to look.
Jeff

I then listed some motions and asked of you were confirming them as components of the second fire:

Ok, so if you are confirming that the second fire constitutes motion other than pure (about the pelvis vertical axis) pelvis rotation - for example hip extension and/or pelvis posterior tilt, then I am happy to agree with you and I can tell you that you have cleared up what 300+ posts in two threads on FB did not clear up. This seems like great progress.

You are correct that those motions are not presented in the downswing kinematic sequence graph, which is on page 5 of the AMM biomechanics report. They are on page 11. That information is on pages 9 and 10 in our report and is also on page 10 of the GBD report.

You never confirmed or denied them being components. Instead, you chose to focus your next post on name calling and other petty, time-wasting posts, like calling Nick a shit-for-brains.

So, I listed those two motions, and then told you were you could find them in an AMM report, in our report, and in a GBD report.

To review at this point:
I told you what was on those pages.
That is in fact the information on those pages.
You and I both posted examples of that data being on those pages.
And you called me a liar.

I notice that you intentionally edited out that I specifically listed those two components and then said where you could find them.
It is clear you would rather call people names than have a discussion of the golf swing. I think you might want to rename your blog JeffyNameCalling, or actually discuss the golf swing.

So let's get back to your example:
The classroom instructor needs to first ACTUALLY DEFINE the term. Not say, "everyone knows it", or "Someone else said what it was".
When a student asks "Is this what you mean", you do not call someone else a "shit-for-brains", you answer the question.

When a student presents the information he exactly said he would (remember, I specifically listed hip extension and pelvis tilt, and then told you where they could be found), you do not call him a bullshitter. You may feel the answer is wrong, but you don't pull derogatory names out of your ass and start throwing them around. If it is not the information you wanted, you then must actually say what you had meant.

Now let's get to your definition of the second fire:

The AMM data sheet shows you range of motion of the hips - You said you wanted movement of the hips (I understand you want motion throughout the swing, you know how to find that).
Let's take note that I included hip data based on some of your other comments. As weakly and vaguely as you define the second fire, you do state that the second fire is "motions caused by shear forces." Hip extension is not caused by shear force, so you either didn't mean to include hip extension, or you don't know what shear forces are. Pelvis rotation and velocity, which I also gave you are created by shear forces.

So, once again, please specifically define the second fire. Please note that flexion and extension of the knee and hip require normal (vertical) forces in the golf swing, so it appears that would you have said so far is either wrong or incomplete. Understand that there are about 42 different "motions of the legs and hips", if you look at both sides, and that is if you do not include motion at the ankle.

So Jeff, end the name calling. End the waste of everyone's time.

WHAT EXACTLY IS THE SECOND FIRE?

Jeff Martin
June 13th, 2014, 04:40 PM
Jeff,

I have probably asked you a half dozen times what the second fire is. Originally it was understood to be a second acceleration of the pelvis axial rotation. You have never actually answered the question. the closest you have come is this:


I think we all know what the second fire is. The first fire is by the spine engine and initiates the downswing, and the second fire are movements of the legs and hips which add power through shear forces. We know the second fire doesn't show up in the kinetic sequence charts produced by AMM/TPI. That's why you have to look elsewhere and Kel has told you where to look.
Jeff

I then listed some motions and asked of you were confirming them as components of the second fire:


Ok, so if you are confirming that the second fire constitutes motion other than pure (about the pelvis vertical axis) pelvis rotation - for example hip extension and/or pelvis posterior tilt, then I am happy to agree with you and I can tell you that you have cleared up what 300+ posts in two threads on FB did not clear up. This seems like great progress.

You are correct that those motions are not presented in the downswing kinematic sequence graph, which is on page 5 of the AMM biomechanics report. They are on page 11. That information is on pages 9 and 10 in our report and is also on page 10 of the GBD report.

You never confirmed or denied them being components. Instead, you chose to focus your next post on name calling and other petty, time-wasting posts, like calling Nick a shit-for-brains.

So, I listed those two motions, and then told you were you could find them in an AMM report, in our report, and in a GBD report.

Since I hadn't responded to your post and acknowledged that those components were part of the second fire, logically, your statement that I was "correct that those motions are not presented in the downswing kinematic sequence graph" applied to the motions I had mentioned: "movements of the legs and hips which add power through shear forces." In any case, the hip extension data on page 11 is useless and non-responsive. BTW, the pelvis data you posted from your report is part of the standard AMM/TPI graphs, so I didn't need you to tell me where to find it. The hip and leg data I was referring to is not: that's why I said it was missing.


To review at this point:
I told you what was on those pages.
That is in fact the information on those pages.
You and I both posted examples of that data being on those pages.
And you called me a liar.

I notice that you intentionally edited out that I specifically listed those two components and then said where you could find them.

I think that comment falls into the category of "plain old stupidity" rather than lying. My copies of your posts are unedited.


It is clear you would rather call people names than have a discussion of the golf swing. I think you might want to rename your blog JeffyNameCalling, or actually discuss the golf swing.

Not really. I just don't let anyone wriggle off the hook, no matter how many times they deny wrongdoing. You should know that by now.


So let's get back to your example:
The classroom instructor needs to first ACTUALLY DEFINE the term. Not say, "everyone knows it", or "Someone else said what it was".
When a student asks "Is this what you mean", you do not call someone else a "shit-for-brains", you answer the question.

When a student presents the information he exactly said he would (remember, I specifically listed hip extension and pelvis tilt, and then told you where they could be found), you do not call him a bullshitter. You may feel the answer is wrong, but you don't pull derogatory names out of your ass and start throwing them around. If it is not the information you wanted, you then must actually say what you had meant.

Now let's get to your definition of the second fire:

The AMM data sheet shows you range of motion of the hips - You said you wanted movement of the hips (I understand you want motion throughout the swing, you know how to find that).
Let's take note that I included hip data based on some of your other comments. As weakly and vaguely as you define the second fire, you do state that the second fire is "motions caused by shear forces." Hip extension is not caused by shear force, so you either didn't mean to include hip extension, or you don't know what shear forces are. Pelvis rotation and velocity, which I also gave you are created by shear forces.

I did not state "that the second fire is 'motions caused by shear forces'". Chalk another one up to "plain old stupidity".


So, once again, please specifically define the second fire. Please note that flexion and extension of the knee and hip require normal (vertical) forces in the golf swing, so it appears that would you have said so far is either wrong or incomplete. Understand that there are about 42 different "motions of the legs and hips", if you look at both sides, and that is if you do not include motion at the ankle.

So Jeff, end the name calling. End the waste of everyone's time.

WHAT EXACTLY IS THE SECOND FIRE?

I have more than once directed you to the source document where Kelvin defines the movements of the second fire in detail, and gone so far as to show you exactly where the relevant discussion begins. Please stop wasting my time asking for information you already know how to get. If you haven't figured out what the second fire is by now, you safely fall into the "shit-for-brains" category.




Jeff

Mike Duffey
June 13th, 2014, 04:55 PM
I think that comment falls into the category of "plain old stupidity" rather than lying. My copies of your posts are unedited.

Jeff

Jeff, here is my original post:


Ok, so if you are confirming that the second fire constitutes motion other than pure (about the pelvis vertical axis) pelvis rotation - for example hip extension and/or pelvis posterior tilt, then I am happy to agree with you and I can tell you that you have cleared up what 300+ posts in two threads on FB did not clear up. This seems like great progress.

You are correct that those motions are not presented in the downswing kinematic sequence graph, which is on page 5 of the AMM biomechanics report. They are on page 11. That information is on pages 9 and 10 in our report and is also on page 10 of the GBD report.

And here is a what you 'copied as my post'

3049

Did the rest of my post magically delete itself? Because that is the part where I said... Are we talking about hip and pelvis data? This is where you can find hip and pelvis data.... (paraphrasing slightly).

And before you dig yourself a bigger hole, hitting the delete key does constitute editing.

Mike Duffey
June 13th, 2014, 05:00 PM
I did not state "that the second fire is 'motions caused by shear forces'". Chalk another one up to "plain old stupidity".
Jeff


I think we all know what the second fire is. The first fire is by the spine engine and initiates the downswing, and the second fire are movements of the legs and hips which add power through shear forces. We know the second fire doesn't show up in the kinetic sequence charts produced by AMM/TPI. That's why you have to look elsewhere and Kel has told you where to look.


Jeff

Either
1. You have no idea what you wrote
2. You are bullshitting again
or 3) you can now explain how "add power through shear forces" is not something caused by shear forces.

Which is it Jeff? These are your own words...

Jeff Martin
June 13th, 2014, 05:20 PM
Jeff, here is my original post:


Ok, so if you are confirming that the second fire constitutes motion other than pure (about the pelvis vertical axis) pelvis rotation - for example hip extension and/or pelvis posterior tilt, then I am happy to agree with you and I can tell you that you have cleared up what 300+ posts in two threads on FB did not clear up. This seems like great progress.

You are correct that those motions are not presented in the downswing kinematic sequence graph, which is on page 5 of the AMM biomechanics report. They are on page 11. That information is on pages 9 and 10 in our report and is also on page 10 of the GBD report.

And here is a what you 'copied as my post'

3049

Did the rest of my post magically delete itself? Because that is the part where I said... Are we talking about hip and pelvis data? This is where you can find hip and pelvis data.... (paraphrasing slightly).

And before you dig yourself a bigger hole, hitting the delete key does constitute editing.



I copied that post in its entirety in the initial post where I said you were "fibbing", post #41:


3050


In post #44, I didn't post the whole thing, fair enough. I didn't see any reason to: the relevant part was where you stated "motions" were represented on page 11 of the AMM report, and they weren't.

In post #53, I copied that post in its entirety, so, obviously, I was never trying to hide the first paragraph.





Jeff

Jeff Martin
June 13th, 2014, 05:27 PM
I did not state "that the second fire is 'motions caused by shear forces'". Chalk another one up to "plain old stupidity".
Jeff


I think we all know what the second fire is. The first fire is by the spine engine and initiates the downswing, and the second fire are movements of the legs and hips which add power through shear forces. We know the second fire doesn't show up in the kinetic sequence charts produced by AMM/TPI. That's why you have to look elsewhere and Kel has told you where to look.


Jeff

Either
1. You have no idea what you wrote
2. You are bullshitting again
or 3) you can now explain how "add power through shear forces" is not something caused by shear forces.

Which is it Jeff? These are your own words...

The extension of the hips, the primary power component of the second fire, is driven by the contraction of the gluteus maximus. How is contraction of a muscle caused by "shear forces"? My understanding is that shear forces are created where the feet and ground interact, and would result from asymmetric extension of the legs and hips, through a force couple.






Jeff

Jeff Martin
June 13th, 2014, 05:39 PM
I just remembered this:



Let's take note that I included hip data based on some of your other comments. As weakly and vaguely as you define the second fire, you do state that the second fire is "motions caused by shear forces." Hip extension is not caused by shear force, so you either didn't mean to include hip extension, or you don't know what shear forces are. Pelvis rotation and velocity, which I also gave you are created by shear forces.



So, I guess we agree.





Jeff

Mike Duffey
June 13th, 2014, 06:02 PM
The extension of the hips, the primary power component of the second fire, is driven by the contraction of the gluteus maximus. How is contraction of a muscle caused by "shear forces"? My understanding is that shear forces are created where the feet and ground interact, and would result from asymmetric extension of the legs and hips, through a force couple.

Jeff

Jeff,,
This post is finally about the golf swing. I am willing, right now, to drop all of the pants-on-fire stuff and talk about the willing to talk about the golf swing. Are you willing to do this as well?

Jeff Martin
June 13th, 2014, 06:23 PM
Sure.




Jeff

Mike Duffey
June 15th, 2014, 08:51 PM
The extension of the hips, the primary power component of the second fire, is driven by the contraction of the gluteus maximus. How is contraction of a muscle caused by "shear forces"? My understanding is that shear forces are created where the feet and ground interact,

A shear force is typically defined as a force that acts parallel to a surface or perpendicular or perpendicular to the extension of the substance (note that this is not "knee extension", this is more of a materials testing definition, so extension in this case would be would be like pulling both ends ends of he femur away from each other).

So yes, in general, all forces that are horizontal and act parallel to the ground woul dbe considered shear forces. But shear forces can also occur at joints, and in fact the very often do. For example, the quadriceps can act to actually pull the tibia forward, not just rotating it about the knee joint center. This may actually be a possible mechanism for ACL tear (The hamstrings should contract somewhat to prevent the forward shearing of the tibia relative to the femur.

So, muscles can and do create shear, but it is almost always very small (the quadriceps are one of the few that can really do this and that is because the patella gives them a mechanical advantage). But this kind of shear does not help joint motion. As mentioned above, the antagonist muscle (the 'opposite acting' muscle) will almost always contract to help prevent the shearing motion and allow for rotation only.


My understanding is that shear forces are created where the feet and ground interact, and would result from asymmetric extension of the legs and hips, through a force couple.
Jeff
Shear forces are caused by many things, but not really by the 'asymmetric extension' you describe. Simply twisting your spiked golf shoe on the ground will create shear forces. Pushing sideways with your shoe will create shear forces.

A force couple is actually a very, very specific combination of forces that result in perfect rotation without any horizontal translation. That wouldn't apply in this context.

Jeff Martin
June 15th, 2014, 10:16 PM
A shear force is typically defined as a force that acts parallel to a surface or perpendicular or perpendicular to the extension of the substance (note that this is not "knee extension", this is more of a materials testing definition, so extension in this case would be would be like pulling both ends ends of he femur away from each other).

So yes, in general, all forces taht are horizontal and act parallel to the ground woul dbe considered shear forces. But shear forces can also occur at joints, and in fact the very often do. For example, the quadriceps can act to actually pull the tibia forward, not just rotating it about the knee joint center. This may actually be a possible mechanism for ACL tear (The hamstrings should contract somewhat to prevent the forward shearing of the tibia relative to the femur.

So, muscles can and do create shear, but it is almost always very small (the quadriceps are one of the few that can really do this and that is because the patella gives them a mechanical advantage). But this kind of shear does not help joint motion. As mentioned above, the antagonist muscle (the 'opposite acting' muscle) will almost always contract to help prevent the shearing motion and allow for rotation only.


Shear forces are caused bu many things, but not really by the 'asymmetric extension' you describe. Simply twisting your spiked golf shoe on the ground will create shear forces. Pushing sideways with your shoe will create shear forces.

A force couple is actually a very, very specific combination of forces that result in perfect rotation without any horizontal translation. That wouldn't apply in this context.

Guess I misunderstood Dr. Kwon. Or you two don't agree.




Jeff

Mike Duffey
June 16th, 2014, 02:18 PM
It would probably help if you could post (or at least paraphrase) what he said, in context.

Jeff Martin
June 16th, 2014, 03:17 PM
It would probably help if you could post (or at least paraphrase) what he said, in context.



That might be helpful for you, but boring for me. I have a better idea. Why don't you put a post together using Jamie Sadlowski as a model and identify the major forces involved in his second fire (just the lower body)? Be sure to tell us which are shear forces and which are some other kind. You can also comment on why his hip rotation during the second fire isn't a result of a force couple. You can use these:



http://youtu.be/yPx74zqaXBw


http://youtu.be/vVbDVcUq9lc


http://youtu.be/5f-tGAFgNfA



Thanks!






Jeff

Mike Duffey
June 16th, 2014, 10:53 PM
Jeff,
What's the point of saying we don't agree if you are not willing to follow up with what we disagree about?

Clearly you thought the topic was interesting and important enough for you to ask so your saying now that it is boring doesn't make any sense.

Please go ahead and share what we disagree about rather than divert the topic; we can talk about Jamie soon enough.

Jeff Martin
June 16th, 2014, 10:59 PM
Professor-

Time to carry your weight around here. Just do as I asked, and that will clear everything up. Quit stalling.



Jeff

Mike Duffey
July 6th, 2014, 11:31 PM
Jeff,
When you originally posed the question, I thought you were kidding. I see that you were not and I am really surprised.
I have stated many times that I think it is a bad idea to try to evaluate 3D motions based on 2D images. But that is not as bad an idea as to try to guess forces based on video.

That is entirely the reason to have force plates (or at least pressure plates) - to take as much of the guessing and likely error out of it. To guess about forces based on video like you have posted would be foolish.

So thanks for pointing out why that kind of analysis should be done with equipment meant for measuring forces. I agree that is a good idea.

Jeff Martin
July 7th, 2014, 11:52 AM
Jeff,
When you originally posed the question, I thought you were kidding. I see that you were not and I am really surprised.
I have stated many times that I think it is a bad idea to try to evaluate 3D motions based on 2D images. But that is not as bad an idea as to try to guess forces based on video.

That is entirely the reason to have force plates (or at least pressure plates) - to take as much of the guessing and likely error out of it. To guess about forces based on video like you have posted would be foolish.

So thanks for pointing out why that kind of analysis should be done with equipment meant for measuring forces. I agree that is a good idea.



hmmmm... Dr. Kwon had no reservations talking generally about the forces at play in Jamie's downswing based on videos from several angles. Maybe you should go take a course from him.

Anyhow, until you publish something about golf, it's adios!




Jeff