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Thread: Jamie Sadlowski's hip rotation into impact

  1. #46
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    Quote Originally Posted by Jeff Martin View Post
    Thanks, yeah, I really butchered that one. I should have refreshed my memory instead of relying on "the top of my head". Just as Force = Mass times Acceleration, Torque = Moment of Inertia times Rotational Acceleration. So Rotational Acceleration = Torque divided by Moment of Inertia. If the golfer's MOI increases and the torque applied remains the same, the object's rotational velocity will decelerate. So, to maintain rotational velocity in the downswing, the golfer needs to apply increasing torque in direct proportion to the increase in MOI. For nearly all of the second half of the downswing, Sadlowski appears to be doing that very well.

    As I thought some more about the Sadlowski numbers, I realized I miscounted the number of frames the first time around (last week), so in post #11 above I did not calculate the average rotational velocities in the first and second half of the downswing accurately. I also hadn't noticed then the distortion created by the shortened y-axis.

    Knowing now that from the top to hips square is 17 frames and that his hips were likely at least 50 degrees closed at the top, Sadlowski's hips rotated at an average rate of about 529 degrees per second in that first half of the downswing. From square hips to impact, Jamie's hips rotate about 60 degrees open in 18 frames. That is equal to an average rate of rotation of 600 degrees per second, a 13% increase in average rotational velocity after the hips square. That doesn't exactly square (pun intended) with the following pronouncements:


    Attachment 1400


    Attachment 1401



    Sorry to hear about your wife and her hips. My mom also had both hips replaced so I know it isn't much fun.

    Take care,




    Jeff
    Dear Jeff,

    First, during this Holiday Season, the best of good wishes for you and all the followers of these 'energetic' golf truth-seeking' discussions.

    Sorry for the one month delay in responding, but I have been carefully following the posts on this and other sites and have what I hope will be received as 'value-added', applied science-based comments. I offer these at this time as I understand you, Kelvin and a few others are very busy looking at the data gathered in Phoenix a few weeks ago, and I want to get my thoughts considered as the giant task of data reduction and most importantly, data 'interpretation' is completed.

    There is NO question in my mind that the 'real' conditions of ACTUAL ball/club face impact have a significant influence on the resultant trajectory of the ball to, and after landing. But, the emptiness I feel is that no effort seems to be going towards HOW the impact conditions were created by the golfer, AND what is necessary to change the impact conditions for what ball flight is desired, ESPECIALLY WITH REGARD TO REPEATABILITY AND ACCURACY. This is where I have spent the dominant part of my time in researching and seeking golf truth, and have concluded the answer lies in the need for a better understanding of each golfers dynamic balance and stability characteristics MOSTLY during the explosive downswing.

    As a result of the uniqueness of each golfer, and maybe even each swing, the forces, torques and energies put into the accelerating golf club come from several body elements, and the major contributors include the knees/pelvis, torso, shoulder girdles/scapulae, and finally the lead and trail wrists. How each golfer apportions the contribution of each of these major contributors DURING ANY SWING is a strong function of how it senses the dynamic stability of especially the body as a whole, but also includes the sub elements as noted above.

    If the sensing systems, including many proprioceptive centers (especially the ankles) conclude there are INSTABILITIES coming, there will be UNWANTED reflex actions and swing path and position adjustments that will occur involuntarily, messing up the swing, BUT WILL SHOW UP IN THE DATA YOU ARE REVIEWING, especially the Trackman 'dispersion' data if you had any golfers produce repeated swings.

    More, if you are interested in this area.

    Sincerely,
    Art

  2. #47
    Quote Originally Posted by Jeff Martin View Post
    So Rotational Acceleration = Torque divided by Moment of Inertia. If the golfer's MOI increases and the torque applied remains the same, the object's rotational velocity will decelerate. So, to maintain rotational velocity in the downswing, the golfer needs to apply increasing torque in direct proportion to the increase in MOI.
    This isn't accurate.

    If the golfers' MOI increases and the torque is zero, the rotational velocity will go down. If the rotation speed remains constant, there is a torque applied that is exactly big enough to negotiate the increase in MOI. Of course this means more club head speed too.

    There's a battle between MOI increase and torque that will determine whether the rotational speed increases or decreases at various stages, but a positive torque will always produce swing speed.

    PS Merry Christmas Jeff. It has been very interesting to follow Kelvin's and your investigations in 2012.

  3. #48
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    In November, I was sent the AMM3D analysis of Jamie Sadlowski, but was asked by my source to not post it. Since Manzella has published the analysis on Youtube, I no longer feel bound to keep it confidential. So everyone can see what the graphs actually look like, here they are.

    Kinematic Sequence rotational velocity ("global reference frame", according to Mike Jacobs; y-axis in degrees per second, x-axis is time):




    Pelvis Angles ("local reference frame"; y-axis is in degrees, x-axis is time):





    According to Mike Jacobs, the rotational velocity curve in the top graph is NOT calculated from the angles in the bottom graph. This is confirmed by some simple math. According to the pelvis angles graph, the hips are a little more than 55 degrees closed at the top and a little less than 55 degrees open at impact: let's call it hip rotation during the downswing of about 110 degrees.

    We can see from the time scale that from the top until impact takes about 0.2 seconds. That gives us an average rate of rotation from the top until impact of 550 degrees per second.

    How does this compare to the data I derived from the Motion Reality video Manzella posted in November? This is what I posted at the time (from post #25 in this thread):

    "Depth of field and parallax issues don't factor at all into these simple facts: at the top of the backswing, Sadlowski's hips are at least 50 degrees shut. 17 frames later, the hips are square. That is a rate of rotation of about 530 degrees per second. At impact, 18 frames later, the hips are at least 60 degrees open, a rate of rotation of 600 degrees per second, 13% higher. Is that consistent with a theory that states rotation peaks at hips square and decelerates rapidly after that? No. Falsified."

    I'll save you from having to do the math: that works out to an average rate of rotation from top until impact of 566 degrees per second, a disagreement of just 3%. Looks like we have a match!!!



    Jeff

  4. #49
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    It gets even better...

    Here is the "local reference frame" "Thorax Angles" graph for Jamie (comparable to the "Pelvis Angles" graph above). Kinematic sequence fans, notice anything unusual??? The thorax rotation (red line) is nearly constant from just after the top until well past impact (remember, when looking at angles graphed over time, a line that turns up reflects acceleration, a line that turns down deceleration, a straight sloped line reflects constant rotational velocity, and a line horizontal to the x-axis is zero rotational velocity). Y-axis is angles in degrees, x-axis is time.




    So, how does a thorax that is rotating at a near constant velocity well through impact have a rotational velocity curve that looks like the one below (green line), where velocity peaks well before impact, followed by "massive deceleration"? Y-axis is degrees per second, x-axis is time.




    Answer: "apples" and "oranges"...The "global reference frame" velocity curve is NOT calculated from the "local reference frame" angles.

    After seeing these "local reference frame" graphs from AMM3D, maybe now some more people will understand Tapio's rotational velocity graphs that disagree with the Kinematic Sequence theory, like this one (blue is hip speed, red is shoulder, green is hand and yellow is clubhead; y-axis is degrees per second, x-axis is time):








    Jeff

  5. #50
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    But wait! There's more!!!

    Is anyone at this point surprised that the spine, one of those distal parts of the body relative to the club, also DOES NOT DECELERATE "massively" before impact on a "local reference frame" basis???


    Jamie's AMM3D Spine Rotation Angle, y-axis in degrees, x-axis is time:







    Jeff

  6. #51
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    This adds some clarity...

    From an academic paper that used an AMM3D-predecessor system:

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    And from some AMM product literature:

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    And from the AMM3D website:

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    So, what does this all mean? Piecing it together, "local reference frame" seems to mean relative to each body segment's own sensor and, as a consequence, a "local" axis. So, if the pelvis sensor (sensors?) is aligned accurately with the spine, the AMM3D "pelvis angles" graph should tell you its angle relative to an axis running through the spine. Seems to me like this is where you'd go to learn how the player's pelvis is rotating during the swing and determine, for example, if a player has "massive pelvic deceleration" before impact.

    But, the main Kinetic Sequence rotational velocity graph (which is usually the only graph shown) seems to reflect rotation relative to the "global reference frame": a fixed axis pointing straight up into the air and one pointing at the magnetic North pole! Now, why is that useful information, let alone information that is considered by Manzella as more important than the "local reference frame" data? Damned if I know. Does Manzella even know that the "massive pelvic deceleration" he claims is not relative to the spine, which is how every sensible person would look at it? Not sure I want to know the answer...

    Case closed.



    Jeff

  7. #52
    Lloyd Higley Guest
    Nice work Jeff.

  8. #53
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    Quote Originally Posted by coach View Post
    Nice work Jeff.
    Thanks, coach! And a big thanks to Mike Jacobs whose post yesterday afternoon set in motion the unraveling of this sham!

    I'm still reeling a bit from the realization that Cheetham's own data blew 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



  9. #54
    Lloyd Higley Guest
    Sent you a pm.....

  10. #55
    New update by Manzella ! He got out his protractor on his lines and came up with the degrees of hips opening in a scientific mathematical genius approach .

  11. #56
    Massive deceleration just a whisker before impact

  12. #57
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    Here is the Motion Golf analysis...

    The overhead view of Jamie from the Motion Reality system Manzella posted in November was bootlegged from this fuller presentation:





    What is interesting to note is that this system places a series of markers around Jamie's waist (above the belt line) and on his knees, but nothing in-between! Yet it "shows" rotation of the "hips"!


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    In contrast, AMM3D puts one sensor on the belt line (that's not Jamie, btw):





    As you might guess, AMM3D and Motion Reality get some different numbers. At the top, AMM3D says that Jamie's "pelvis" is more than 60 degrees closed, Motion Reality says Jamie's "hips" are 49 degrees closed. At impact, AMM3D says the "pelvis" is 47 degrees open, Motion Reality says the "hips" are 57.8 degrees open! Which one is "right"? Both? Neither?



    Jeff

  13. #58
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    A nice view of "push/pull"...

    Here's an interesting view of Jamie because it gives you a good look at the "push/pull" rotation around the spine: left leg extension that "pulls" the left hip joint away from the target, and right leg extension that pushes the right hip joint towards the target. When do the legs STOP firing? At "hips square", when "massive pelvic deceleration" allegedly starts??? That looks like where the legs START to fire!












    Jeff

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