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Post by gmbtempe on Jan 15, 2013 16:55:27 GMT -5
This is what MF had to say about the Sadlowski swing AMM measurements in the BM-forum. " According to the AMM data, JS's hips are 9* open when he hits his peak angular velocity (650*/sec)......if he were to keep this angular velocity CONSTANT until impact (about .10 seconds later), his hips would be 65* more open - 74* open at impact......alas, JS's hips are only 47* open at impact due to deceleration.....
We rest our case......our case is rested ". He might rest his case, but that doesn't mean that the case is settled. Those peak angular velocity measurements are not compatible with the pelvic angle graph, which suggests a constant pelvic rotational velocity. So, why should I believe in the accuracy of his calculated peak velocity measurement rather than the accuracy of that pelvic angle graph? Then, MJ starts a thread to state that the measurements of pelvic rotational velocity will be different if one uses a global reference measurement system rather than a local reference measurement system. Why should they be different? If they are different, then how do we know whether one, or both, of those measurements are inaccurate? I have zero belief in the accuracy of any graphs, or calculated rotational velocity measurements, made by those 3-D systems - because they are internally inconsistent, and also externally inconsistent (the pelvic rotational velocity graphs produced by TPI look nothing like the graphs produced by Chris Welch or Tapio). If the three 3-D researchers produce three different graphs, why should I believe in the accuracy of any of the three graphs? Jeff. Finney pulled that down right away last night. His figures were wrong. I've calculated the correct numbers off the AMM3D "pelvis angles" graph and they are almost identical to what I calculated in November off of the Motion Reality video Manzella posted. So who's the lunatic now, Mike??? Manzella needs to reign that guy in. At least I acknowledge I am just learning this stuff, this guy is making statements about the case is closed like he is the judge and jury.
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Post by tomdavis76 on Jan 15, 2013 20:32:18 GMT -5
Finney pulled that down right away last night. His figures were wrong. I've calculated the correct numbers off the AMM3D "pelvis angles" graph and they are almost identical to what I calculated in November off of the Motion Reality video Manzella posted. So who's the lunatic now, Mike??? Manzella needs to reign that guy in. At least I acknowledge I am just learning this stuff, this guy is making statements about the case is closed like he is the judge and jury.If you've read my most recent posts at jeffygolf and Richie's, you now probably know more about these systems than Finney. I'm still reeling a bit from the realization that Cheetham/AMM3D's own data has blown up the kinetic sequence theory! It also amazes me that this now quite obvious deception hasn't surfaced before. It is crystal clear from Jamie Sadlowski's "pelvis angles" and "thorax angles" graphs that his Kinetic Sequence "rotational velocity" graph is fraudulent! There is NO "massive deceleration" of the pelvis or thorax before impact, let alone a sequential deceleration. Everyone using the system had to know, or should have known, this was true for many golfers, but they all kept touting "deceleration". Needless to say, Kelvin and Rick Malm were 100% right and I very much look forward to watching Manzella try to squirm out of this one. Jeff
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Post by imperfectgolfer on Jan 15, 2013 23:13:21 GMT -5
MF makes yet another foolhardy assertion in the BM-forum thread. MF stated-: " The "apples and oranges" defense has now been nullified and Jamie Sadlowski's hips are doing what 47not74 never could have imagined....
The reference frames are local for both the positional data and the rotational velocity data.....He not nullifying Jeffy's assertions - he is nullifying Mike Jacob's assertion that there is a difference between global and local reference frames that needs to be taken into consideration. Only the local reference frame is relevant, and according to the pelvic angle graph (which is based on the local reference frame), there is a constant pelvic velocity during the downswing, and there is no mid-downswing deceleration phenomenon (as seen in the TPI graphs). As Jeffy implies, it suggests that there is some "gross misrepresentation" in the TPI graph of JS's swing that shows that there is significant mid-downswing pelvic deceleration - when the actual pelvic angle graphs' data do not show any significant (massive) pelvic deceleration pre-impact. I would like to see Cheetham and BM provide an explanation for this discrepancy. Jeff.
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Post by imperfectgolfer on Jan 15, 2013 23:46:31 GMT -5
Mike Jacob stated the following in his BM-forum thread. " The Pelvis Angles {rotation~bend~side bend} are being measured on a different reference frame than the Kinematic Sequence. Kinematic Sequence is on a Global Reference Frame and the Pelvis Angles is on a local reference frame. Trying to compare the 2 and draw conclusions on rotational rates is a waste of everyone's time."If the TPI kinematic sequence graphs are really based on a the global reference system, then it may explain why the TPI graphs show the mid-downswing deceleration phenomena for pelvis and thorax. Jeffy quoted the AMM system global reference system definition as follows from their own literature-: If the TPI are really interpreting pelvic and torso and arm motion using those global references for their TPI graphs, then they must surely be misinterpreting reality - because one needs to use local reference frames to accurately represent reality. Jeff.
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Post by imperfectgolfer on Jan 15, 2013 23:57:19 GMT -5
Here is link to a pdf document produced by TPI on their measurement system for their kinematic sequence. perfectgolfswingreview.net/KinLinkvsKinSeq.pdfTo quote from that article-: " The angular velocity vector of each segment’s motion is then calculated with respect to the global coordinate system; in the case of an electromagnetic system this is in the middle of the transmitter on the tripod behind the golfer. This vector is then resolved into the local coordinate system of the respective body segment and broken into its coordinates around the three local axes of the segment; the inferior-superior, mediallateral, and anterior-posterior axes. For the pelvis and thorax the angular velocity component around the inferior-superior (up-down) axis is used to represent the rotational velocity of that segment." That up-and-down axis is not necessarily the local reference axis required for "correct" measurements of pelvic and thorax rotational velocity if it is truly up-and-down. Or, do the TPI researchers mean "up-and-down" as not being purely vertical, but perpendicular relative to the tilted angle of the pelvis for pelvic rotational measurements and perpendicular relative to the spinal bend inclination angle angle for the thorax rotational measurements? Jeff.
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Post by imperfectgolfer on Jan 16, 2013 0:18:51 GMT -5
Jeffy,
Don't come to premature conclusions!
The TPI researchers also state in their conclusion-: "Each component is calculated around an internal anatomical local axis that moves with the segment. This method does NOT leave the results in the world or global coordinate system."
That suggests a "correct" local reference measurement. However, I still cannot understand why the TPI graph shows massive pelvic deceleration in the mid-downswing while the pelvic angle graph shows a constant pelvic velocity.
You need to research this issue further before declaring victory.
Jeff.
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Post by imperfectgolfer on Jan 16, 2013 0:46:45 GMT -5
Jeffy, Here is a link to more TPI material - you can download the pdf file. www.advancedmotionmeasurement.com/Portals/0/articles/BiomechComparativeFullReport.pdfNote that they mention rotation angles and present a graph on page 76 which looks exactly like those pelvis and thorax rotation graphs that you presented. That represents the "true angles" required for rotational measurement because they are measured with reference to the "local up/down axis where ever that segment is". Note that the rotational angle graphs do not show any deceleration phenomena in the downswing (as seen in their TPI kinetic sequence graphs). I still cannot understand why there is this discrepancy. On page 78, they define spine angle as follows-: " This is the rotation of the thorax with respect to the pelvis as if the pelvis and thorax were brought together to rotate about the same center and a camera on the pelvis looks directly up at the thorax." That may explain why the spine angle rotation graph is not as I originally imagined - as being referenced to the spinal bend inclination angle. The axis of measurement may be different to the spinal bend inclination angle - because it is a "camera angle where the pelvis looks directly up at the thorax" whatever that means. Jeff.
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Post by imperfectgolfer on Jan 16, 2013 1:30:16 GMT -5
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Post by imperfectgolfer on Jan 16, 2013 10:47:56 GMT -5
BM posted this image in his forum's thread. Those measurements suggest that a constant slope (on gross appearance) doesn't imply a constant speed of pelvic rotation, and that would mean that Jeffy's argument falls apart. If those pelvic angle measurements are correct because careful evaluation of the slope shows that it is flattening, then it clears up the discrepancy between the pelvic angle graph and the kinematic sequence graph. Also, note that this deceleration phenomenon in BM's photo doesn't just happen pre-impact - it starts happening near P6 when the pelvis is 9 degrees open to the target. It would not surprise me if JS's pelvis does decelerate gradually between P6 and P7 - as shown in the TPI kinematic sequence graph. I think that Jeffy has acquired a too intense "belief" in the value of maximising pelvic rotation in the late downswing and through impact, and he believes that it decreases the risk of flipping and that it allows a golfer to become a DHer. As I have argued in the "hip stalling" thread, I don't believe that it matters if the pelvis decelerates in the later downswing - as long as one can maintain the forward momentum of the FLW/intact LAFW through impact to P7.3+ (which means that one is a DHer). Jeff.
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Post by gmbtempe on Jan 16, 2013 11:11:12 GMT -5
Not enough clear data to make a definitive conclusion for me, the case is not closed IMO as been asserted by some.
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Post by imperfectgolfer on Jan 16, 2013 14:08:15 GMT -5
Greg, I have now discovered that there is significant evidence of correlation between JS's pelvic angle graph and JS's kinetic sequence graph. For example, there is very little deceleration in that first 0.05 seconds in that BM graph - when the pelvis opens 13.3 and 11.5 degrees respectively, and the pelvic slowing mainly happens in the last 0.05 seconds of the downswing, which is nearer impact. How much nearer to impact is 0.05 seconds? Consider this TPI graph of JS's swing. The standard TPI kinematic sequence graph is on the left, and JS's kinematic sequence graph is on the right. The yellow colored area represents a zone of ~0.05 seconds before impact. Note that the yellow zone correlates with the time when the red curve drops down (representing pelvic deceleration). Note that JS's pelvic velocity graph shows a domed-shaped peak pelvic velocity area where he maintains his peak pelvic velocity with little deceleration - compared to the standard TPI graph where the pelvic velocity drops much more precipitously after the golfer reaches peak pelvic velocity. In other words, although JS doesn't manifest massive pelvic deceleration (which BM claims that all golfers exhibit), he does show some pelvic deceleration in the last 0.05 seconds of his downswing action. Jeff.
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Post by imperfectgolfer on Jan 16, 2013 14:21:56 GMT -5
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Post by gmbtempe on Jan 16, 2013 14:38:02 GMT -5
It would be nice for Kelvin to use a Phantom sequence so I can see the club position 0.05' before impact, where is this, P?,
Is that P6? I wold imagine its like P6.8, are right before impact. In order to snap the kinetic chain as was recommended by BM (not sure if his recent view has changed but he talks about it in his videos I bought) I would imagine you would have to intentionally slow down the pelvis, considerably, just after P6.
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Post by gmbtempe on Jan 16, 2013 14:48:28 GMT -5
And just think if no one questioned anything, if the case was truly closed, then Jacobs and Finney would be telling students or peers two different stories.
In the end I think this is a good exaple why people should question statements and not just accept everything as a fact.
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Post by imperfectgolfer on Jan 16, 2013 21:32:50 GMT -5
Jeffy,
I cannot really understand what you are doing with those graphs.
Can you simply explain in prose language whether you now believe that JS's pelvic rotation is slowing down during his downswing action and do you now believe that he is decelerating down to a rotational velocity of 50% of his peak velocity by impact?
Jeff.
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