Post by dubiousgolfer on May 20, 2022 8:00:42 GMT -5
Dr Mann
Have you seen Dr Kwon's recent video about swing events and phases? Do you think that it's better than the P system to analyse the golf swing?
Look at the graphs below for a typical golfer swing recorded/measured on his 3D system.
The section of the graph that I found interesting was between the 2 yellow pointer arrows (which I inserted myself) from the top of the backswing (TB) to just before lead arm horizontal in the downswing (EDA or P5 ). You can see that the angular velocity graphs of the shoulder line (SL) , Upper lead arm (UL) and the Club are all rotating virtually together as a unit up to the 'Release' point (MC) where the lead wrist starts to uncock.
You can also see that 'Release' (PA#2 -uncocking of the lead wrist) at MC position starts happening just before lead arm horizontal (EDA/P5).
DG
Last Edit: May 20, 2022 8:06:15 GMT -5 by dubiousgolfer
Have you seen Dr Kwon's recent video about swing events and phases? Do you think that it's better than the P system to analyse the golf swing?
Look at the graphs below for a typical golfer swing recorded/measured on his 3D system.
The section of the graph that I found interesting was between the 2 yellow pointer arrows (which I inserted myself) from the top of the backswing (TB) to just before lead arm horizontal in the downswing (EDA or P5 ). You can see that the angular velocity graphs of the shoulder line (SL) , Upper lead arm (UL) and the Club are all rotating virtually together as a unit up to the 'Release' point (MC) where the lead wrist starts to uncock.
You can also see that 'Release' (PA#2 -uncocking of the lead wrist) at MC position starts happening just before lead arm horizontal (EDA/P5).
DG
I can understand the value of Kwon's event phases because it fits in with his didactic approach to how swing events should unfold. Therefore, it makes it easier to follow Kwon's verbal description of events. However, it does not help us to understand the golf swing better. So, for example, Kwon talks about event phases between P3 => P4 where the pelvis/thorax/arms stop rotating in a specific sequence in Kwon's swing model. However, I disagree that every golfer should follow that pattern. For example, I noted in my recent analysis of Will Zalatoris' driver swing that he stops his clockwise pelvic rotation at P3 (which is earlier than Kwon's recommendation). Also, Kwon wants the pelvis to start rotating counterclockwise between P3.5 => P4 (during his transition phase), but many pro golfers (eg. Scottie Scheffler and Hideki Matsuyama) only start to rotate their pelvis counterclockwise starting at P4.
I also disagree with Kwon's didactic kinematic sequence model where the pelvis/thorax and lead arm all rotate at the same angular velocity until the release point. That pattern is only seen in a subset of pro golfers (eg. Ernie Els and Steve Stricker) in the following Cheetkam kinematic sequence graphs.
The reality of "real life" pro golfer golf swings is much more messy. Look at the kinematic sequence graphs of Rickie Fowler, Zach Johnson and Jordan Spieth to see how variable the kinematic sequence can be in PGA tour pro golfers. Also, the idea that PA#2 must start to release at P5 in every pro golfer is also obviously invalid based on simply looking at these graphs, and also based on common sense observation studies (where we observe that pro golfers vary in how long they maintain clubhead lag by noting variances in their efficacy of performing an "active trail arm adduction maneuver that is combined with an pitch elbow motion of the trail arm" that allows the power package to remain intact for longer thereby resulting in a later release pattern).
Another Dr Kwon video regarding functional swing plane but this time he categorises golfers according to the steepness of their FSP.
Steep FSP = Arm-dominant golfer Average FSP = Body Driven golfer Flat FSP = Bent Knee golfer
He is also opining that it is the golfers height that has some strong correlation with the steepness of the FSP.
DG
I think that this Kwon video is very unscientific and frankly nonsensical.
To claim that that a steep FSP is due to an arm-driven swing action is unscientific nonsense. Jamie Sadlowski and many long-drive competitors come down the TSP (which is a steep plane) and they all use a pivot-driven golf swing action.
Also, to claim that a flat swingplane (eg. close to the handplane) is due to a bent knee phenomenon is unscientific nonsense because pro golfers who come into impact very close to the hand plane (eg. Ben Hogan and Matt Kuchar and Hunter Mahan) do not manifest a bent-knee problem.
Kwon does not take into account stylistic choices in terms of whether the golfer comes into impact with an extended lead arm and a small accumulator #3 angle (eg. Phil Mickelson) versus coming into impact with a vertical lead arm and a large accumulator #3 angle (eg. Sergio Garcia). He also does not consider the effect of lead hand grip choice on the likelihood of coming into impact steeper (eg. mid-palmar or high-palmar lead hand grip) or shallower (eg. finger grip).
It is obvious that a taller golfer will likely have a steeper VSP - presuming that they are "average" in terms of their stylistic choice of lead arm angle/accumulator #3 angle.
However, Kwon should also consider a golfer's degree of spinal bend inclination.
Note that Keegan Bradley (image 1) has a very bent-over posture, which could predispose to a flatter VSP at impact, while Brian Gay (image 2) has a more erect posture, which could predispose to a steeper VSP at impact.
Post by dubiousgolfer on Jun 5, 2022 20:34:47 GMT -5
Looks like Dr Kwon is going to have a series of mini-talks (2 hour sessions) as explained in his announcement you-tube video below. The you-tube videos of these talks will be published as private but made available to those who submit an email address associated with their you-tube account, for a period of 6 months.
DG
Last Edit: Jun 5, 2022 20:35:29 GMT -5 by dubiousgolfer
I agree with DG that Kwon stated that one should use an active wrist motion, which he called "snapping the wrists" and he also claimed that it would slow down the rotary motion of the torso.
Both claims make no sense to me.
What does Kwon mean when he states that a golfer should actively snap the wrists to induce the release of PA#2? In his "forces/torques that are applied to the club handle" explanations he never discussed the application of an active wrist torque and he stated that the club releases when the trail hand's positive torque decreases starting between P5 => P5.5 while the MoF produced by the lead hand simultaneously starts to increase.
Here is Kwon's graph.
There is no evidence of an active wrist snapping maneuver in those graphs.
Also, how could an active wrist snapping maneuver cause the torso's rotation to slow down?
I am really surprised to see Kwon talk in such a non-scientific manner.
Jeff.
Dr Mann
I raised the question again to Dr Kwon about his claim that active wrist action slows the torso rotation down.
This was his reply
"This is related to the concept of momentum transfer. Between two interacting body parts, if one side gains momentum due to the force/torque action, the other side loses the same amount of momentum due to the reaction. So slowing down of a body part by accelerating the other part occurs at every level of the body.
Wrist action helps club motion but slows down the hands/arms. Shoulder action helps the arm motion but slows down the thorax, etc."
He never mentioned before that increased shoulder girdle action would also be required to prevent the slowing of the arms (caused by active wrists). This makes sense now from a kinetics perspective, but I don't remember him advising the golfer to do both biomechanical actions unless he is assuming that the golfer will naturally increase the use of his shoulder girdle muscles to prevent the slowing of his arms.
DG
Last Edit: Oct 30, 2022 8:31:08 GMT -5 by dubiousgolfer
Post by imperfectgolfer on Oct 30, 2022 9:27:52 GMT -5
DG,
You quoted Kwon as follows-: ""This is related to the concept of momentum transfer. Between two interacting body parts, if one side gains momentum due to the force/torque action, the other side loses the same amount of momentum due to the reaction. So slowing down of a body part by accelerating the other part occurs at every level of the body."
I would not dispute the bold-highlghted statements if it were true that there was fixed amount of energy (momentum) between interacting body parts. However, in a full golf swing action there does not have to be a fixed amount of energy between interacting body parts and a golfer can input more energy into that scenario if that is his intention.
I agree that the body and lead arm rotational velocity decreases after P5.5 in a pro golfer's full golf swing action, but I don't believe that it is a reactive response secondary to the release of PA#2. I believe that it happens naturallyby design so that there is time to complete the release of PA#2/PA#3. In other words, an athletic golfer could deliberately prevent the slowing down of the rotational velocity of the body/lead arm that happens between P5.5 => P7, but then he would never be able to complete the release of PA#2/PA#3 with perfect timing to ensure that he has the perfect amount of forward shaft lean and also a perfectly square clubface at impact. A skilled pro golfer has obviously learned how to perfectly sequence his kinematic sequence so that he can get perfect clubhead/clubface conditions at impact and it does not happen solely due to the physics underlying the COAM principle.
Post by dubiousgolfer on Oct 30, 2022 9:45:00 GMT -5
Dr Mann
Yes, I am in agreement with what you've said above.
Also, Dr Kwon has assumed some cause and effect, that an active wrist action will automatically promote more shoulder girdle motion, etc, which may not necessarily happen.
DG
Last Edit: Oct 30, 2022 9:50:05 GMT -5 by dubiousgolfer
Post by dubiousgolfer on Nov 2, 2022 21:22:39 GMT -5
There is a person called GLK on Golfwrx who has been attending some biomechanics certification courses taught by Dr Kwon. Thought it would be useful to post some of the content he has collected from those courses.
Glk
Yes dr kwon is certainly evolving his instruction during these reprogramming sessions. He does a lot on body movement before he gets into step drills.
I'm in the middle of his certification level 2 class (have attended 6 mini talks and was kwonified via taking his certification level 1. These sessions are focusing on sharing data/info from elite swings on his key research findings - my head was ready to explode after this mornings session. I’ve rewatched the mini talks but these two certifications sessions are going to take some reviewing and time to digest.
lots of information on the functional swing plane and the hand motion path and how they interact for better and worse. He defines 3 swing styles based on how the club head’s path differs from a persons projected FSP and things get complicated when the hand plane and FSP don’t play nice together. His work to get people to modify the direction they swing their hands as in the video is what he views as important to developing his planar swing style where the FSP and hand motion plane are parallel and well aligned. Issues happen which require wrist actions to “save” when the FSP and hand plane have severe directional gaps.
But two items keep coming back up and that is the importance of the vertical and horizontal rhythm in the swing motion. Shurn will get you the horizontal. Shifting and pushing the ground hard with the trail leg and getting the right side as high as you can sets up the vertical - his tap, tap tap - unweighting from p3 to p4 is really important to create a large moment arm and high torque by p5. The large vertical force from the lead leg comes from slowing the drop from unweight ending and not from an attempt to jump - attempting to squat and jump is poor use of the ground and screws up sequencing and lead to the pelvis collapsing and reduced ability to push the ground with the lead leg. Good swings that use the ground well don't squat - the body’s com shifts upward, drops via unweighting and gravity thru transition and early downswing, and then rises again thru impact.
He has lots of good detail on the pelvis motion too. And it is not what I thought, and it challenges TPI concept of ee (early extension). Pelvis com moves a few cm toward the ball until end of pelvis rotation, then move away but never gets back to it starting position. He is not a fan of butt against the wall, ball, or whatever - believes it promotes collapsing of pelvis and poor use of ground 'y e yang' was used as an example. He plays his stick figures from different angles to show motions and how com etc move in poor motions and good - defined based on how well the ground is used.
I'm still digesting and don’t claim expertise. Like I said info packed and really requires multiple views and questions - he is great about responding. He plans a third certification where you’ll be able to run his software on swings and make a diagnosis.
These graphs show the motion.
Question Raised by another poster: Interesting on the EE, I understand the center of pelvis going towards ball a small amount on backswing, your trail side rear would still be deep to be touching “tush line”. So he doesn’t want you to keep your butt back on the tush line through downswing? What does collapsing pelvis mean.
Glk reply: He is not concerned with it and doesn’t view it as ee given the amount and pattern he sees in quality swings. He is concerned that focus on keeping the butt back can lead to negative effects on using the ground.
This is his chart summary of his database of elite swings. Yes, there is variation, and some do keep/get the pelvis com back to or further back than the starting point. He has charts of average plus ranges. And this can be accompanied with maintaining knee flex too long so pelvis “collapses” and ability to push with lead leg is reduced.
This forward movement is not large - on average about an inch with ranges from -1 to 7 cm. He includes swings with driver, 5i, and pw for all golfers and things differ slightly but he typically presents driver data. Have to note that this is all tied together with how the pelvis is rotated. The pattern is toward, away, toward and he has data on all of these segments. But that is really getting into the weeds. He recognizes that excessive forward or backward is an issue - concierge that wall type drills can be overdone.
He played an animation viewed from above on how the pelvis com moves in response to a question basically saying really it moves forward. I asked him for a copy and if he sends it to me I’ll post it - good to see how this forward/backward motion works together with the lateral motion and rotation.
GLK On pelvis com. He notes that the right hip moves back way less than the lead hip moves forward which causes the com to move forward. This is due to the high amount of force on the trail hip during the backswing which makes it hard to move it back a lot and the unweightening if the lead leg allow it to move forward more. The initial shift is important in getting to be able to stand on the trail foot and push up hard and getting the right side up a lot - Kyle Berkshire is this on steroids.
Yep his data clearly shows that the motion is to raise the body com then the vertical force is used to brake the downward motion . A squat entails lowering then raising but the swing motion is opposite - raise then stop the drop. And this motion comes from folks across the spectrum - just that some folks are much better at the pattern.
This is the animation of grant Waite's swing view from overhead. I had to copy to desktop and post since the link is on a private drive.
You can see that from setup to to almost TB the pelvis center moves toward the ball then away thru the downswing but doesn't quite make it back to the setup position.
Dr Kwon described his 3D system at high level. 10 high speed cameras at 500 Hz.68 body markers (GEARS has 28 I believe)
And the markers are attached to bare skin as much as possible to avoid measure error induced by marker movement independent of body (an issue he has seen in systems like Kvest, AMM). Also, the markers are used for error avoidance since body motion is calculated via multiple markers not just one - so the system tracks the relative motion of the markers too
DG
Last Edit: Nov 2, 2022 21:24:19 GMT -5 by dubiousgolfer
There is a person called GLK on Golfwrx who has been attending some biomechanics certification courses taught by Dr Kwon. Thought it would be useful to post some of the content he has collected from those courses.
Glk
Yes dr kwon is certainly evolving his instruction during these reprogramming sessions. He does a lot on body movement before he gets into step drills.
I'm in the middle of his certification level 2 class (have attended 6 mini talks and was kwonified via taking his certification level 1. These sessions are focusing on sharing data/info from elite swings on his key research findings - my head was ready to explode after this mornings session. I’ve rewatched the mini talks but these two certifications sessions are going to take some reviewing and time to digest.
lots of information on the functional swing plane and the hand motion path and how they interact for better and worse. He defines 3 swing styles based on how the club head’s path differs from a persons projected FSP and things get complicated when the hand plane and FSP don’t play nice together. His work to get people to modify the direction they swing their hands as in the video is what he views as important to developing his planar swing style where the FSP and hand motion plane are parallel and well aligned. Issues happen which require wrist actions to “save” when the FSP and hand plane have severe directional gaps.
But two items keep coming back up and that is the importance of the vertical and horizontal rhythm in the swing motion. Shurn will get you the horizontal. Shifting and pushing the ground hard with the trail leg and getting the right side as high as you can sets up the vertical - his tap, tap tap - unweighting from p3 to p4 is really important to create a large moment arm and high torque by p5. The large vertical force from the lead leg comes from slowing the drop from unweight ending and not from an attempt to jump - attempting to squat and jump is poor use of the ground and screws up sequencing and lead to the pelvis collapsing and reduced ability to push the ground with the lead leg. Good swings that use the ground well don't squat - the body’s com shifts upward, drops via unweighting and gravity thru transition and early downswing, and then rises again thru impact.
He has lots of good detail on the pelvis motion too. And it is not what I thought, and it challenges TPI concept of ee (early extension). Pelvis com moves a few cm toward the ball until end of pelvis rotation, then move away but never gets back to it starting position. He is not a fan of butt against the wall, ball, or whatever - believes it promotes collapsing of pelvis and poor use of ground 'y e yang' was used as an example. He plays his stick figures from different angles to show motions and how com etc move in poor motions and good - defined based on how well the ground is used.
I'm still digesting and don’t claim expertise. Like I said info packed and really requires multiple views and questions - he is great about responding. He plans a third certification where you’ll be able to run his software on swings and make a diagnosis.
These graphs show the motion.
Question Raised by another poster: Interesting on the EE, I understand the center of pelvis going towards ball a small amount on backswing, your trail side rear would still be deep to be touching “tush line”. So he doesn’t want you to keep your butt back on the tush line through downswing? What does collapsing pelvis mean.
Glk reply: He is not concerned with it and doesn’t view it as ee given the amount and pattern he sees in quality swings. He is concerned that focus on keeping the butt back can lead to negative effects on using the ground.
This is his chart summary of his database of elite swings. Yes, there is variation, and some do keep/get the pelvis com back to or further back than the starting point. He has charts of average plus ranges. And this can be accompanied with maintaining knee flex too long so pelvis “collapses” and ability to push with lead leg is reduced.
This forward movement is not large - on average about an inch with ranges from -1 to 7 cm. He includes swings with driver, 5i, and pw for all golfers and things differ slightly but he typically presents driver data. Have to note that this is all tied together with how the pelvis is rotated. The pattern is toward, away, toward and he has data on all of these segments. But that is really getting into the weeds. He recognizes that excessive forward or backward is an issue - concierge that wall type drills can be overdone.
He played an animation viewed from above on how the pelvis com moves in response to a question basically saying really it moves forward. I asked him for a copy and if he sends it to me I’ll post it - good to see how this forward/backward motion works together with the lateral motion and rotation.
GLK On pelvis com. He notes that the right hip moves back way less than the lead hip moves forward which causes the com to move forward. This is due to the high amount of force on the trail hip during the backswing which makes it hard to move it back a lot and the unweightening if the lead leg allow it to move forward more. The initial shift is important in getting to be able to stand on the trail foot and push up hard and getting the right side up a lot - Kyle Berkshire is this on steroids.
Yep his data clearly shows that the motion is to raise the body com then the vertical force is used to brake the downward motion . A squat entails lowering then raising but the swing motion is opposite - raise then stop the drop. And this motion comes from folks across the spectrum - just that some folks are much better at the pattern.
This is the animation of grant Waite's swing view from overhead. I had to copy to desktop and post since the link is on a private drive.
You can see that from setup to to almost TB the pelvis center moves toward the ball then away thru the downswing but doesn't quite make it back to the setup position.
Dr Kwon described his 3D system at high level. 10 high speed cameras at 500 Hz.68 body markers (GEARS has 28 I believe)
And the markers are attached to bare skin as much as possible to avoid measure error induced by marker movement independent of body (an issue he has seen in systems like Kvest, AMM). Also, the markers are used for error avoidance since body motion is calculated via multiple markers not just one - so the system tracks the relative motion of the markers too
DG
I have not learned anything new from GLK that Kwon didn't express in his videos that we have already discussed.
DG - have you learned anything new? Do you have any new insights into Kwon's thinking?
Post by dubiousgolfer on Nov 2, 2022 21:46:25 GMT -5
Dr Mann- I haven't found anything new but just thought it would be nice to have any new graphs posted in this thread.
Some more on the kinematic sequence
GLK On the kinematic sequence. HL hip line. SL Shoulder line. UL Arms. Club. WC wrist c0ck. Thorax is omitted but would happen between hl and sl. chart is from 66 players
Dr Kwon breaks things into 3 segments. Backswing, transition, and downswing. The backswing and downswing are partial sequences - they don’t happen in exact proximal to distal order.Transition does.
He spent an hour on 18 charts this is just one. Peak angular velocity has been measured and it has been measured relative to when it occurs in the backswing and downswing. He also measured the change in angular velocity in the downswing between peak and BI.
First in the backswing hl and sl peak within 10 ms. The arms and club are separated from hl and sl and themselves. He correlated all but club to chs. Club doesn’t correlate due to differences in wrist cocking speed and timing.
In the ds all factors correlate to chs.
He doesn’t mention this here but in cert 1 he talked about transition length. Transition is from end of pelvis rotation to top of backswing. Good transition take in the ballpark of 100ms. Quick 60-70 ms - he has one in the 40s and this was also with the player with the shortest arm swing.
In the ds, hl, sl, and arms peak within 10ms. Again partial sequence. And the decel from peak to impact for the hl and arms is correlated to chs - more decel faster chs.
So important to have peak ds angular velocity happen early (and wrist to uncock later). Peaks happen close to the early downswing event - shaft vertical. Important to have sufficient time to transfer speed from body to club. Only the hips and arm decel correlate. The shoulders don’t cause there are a small number of players (5 out of his 66) that keep accelerating the shoulder thru impact - these folks also have an early wrist uncocking, and other sequencing issues. He removed them from the data and has results of just the 61 too. He noted that these are averages and that folks who have really good swings have higher peaks, better delays, etc.
In short active backswing with mature transition and early acceleration. And there you go. So not just amg’s speed up the arms - speed up everything. Peak torque happens by or just before p5 (peak grf happens later but by then the moment arm has shortened). Peak downswing velocity's by shaft vertical. Wrist uncocking happens about shaft vertical too. Gives you about 80-90 ms to decel and transfer momentum.
So peaks are important and when they happen are too - some delayed in backswing and some early in downswing. Example delayed shoulder turn in backswing is good.
Pretty much everything happening soon after transition is good except wrist uncocking.
Here is the data on peak timing prior to impact and relative to ED. They don’t correlate to CHS due to conflicting items. Faster downswing means peaks will be closer to BI but you also need to give enough time before BI for decel to happen for good transfer - still need them to happen as early as possible.
DG
Last Edit: Nov 2, 2022 21:48:41 GMT -5 by dubiousgolfer
Post by dubiousgolfer on Nov 2, 2022 22:36:16 GMT -5
I'm finding Dr Kwon's kinematic graphs confusing because he doesn't use the lead arm angular velocity that I usually see in the kinematic graphs published by 'Phil Cheetham/Dr Greg Rose'. He uses some mathematically calculated 'Upper Lever' concept.
Where is the 'Thorax' angular velocity?
Here is the Upper Lever he uses in his Kinematic graphs.
DG
Last Edit: Nov 2, 2022 22:47:00 GMT -5 by dubiousgolfer
Post by dubiousgolfer on Nov 8, 2022 18:44:01 GMT -5
I asked Dr Kwon about why he uses the UL angular velocity in his kinematic graphs, and this was his reply:
"The UL (upper lever) includes both arms. It actually shows the motion of the hands relative to the hub (mid-trunk). I use the pelvis or HL (hip line), thorax, SL (shoulder line), UL, and club + wrist angular velocities in my KS plot. I prefer UL over lead arm as it shows the motion of both arms.
DG
PS. I've asked him why he didn't include the thorax angular velocity in his kinematic graph.
Reply:
"turn it on/off depending on the situation. In one study we did not include thorax because there were too many graphs."
I also asked him about how he measured the angular velocities of the WC and club in his graphs.
Reply: "The angular velocities we calculated on the functional swing plane (FSP). So axes should be perpendicular to the FSP."
So, the angular velocities for 'body segments/club' we see on his kinematic graphs are not 3D ones but only the components normal to the FSP (whose plane would be theoretically extended back to P4). I'm wondering how his kinematic graphs would change if he used 3D measurements.
Last Edit: Nov 14, 2022 11:56:28 GMT -5 by dubiousgolfer
In analyzing swing theory shouldn't we be looking at research papers rather than instructional videos which are probably providing information relevant to train someone to correct issues indirectly?
In analyzing swing theory shouldn't we be looking at research papers rather than instructional videos which are probably providing information relevant to train someone to correct issues indirectly?
I find research papers too complex and too abstract to understand, so I prefer to analyse what golf researchers state regarding golf swing biomechanics/mechanics when they deal with a "real life" golfer performing a full golf swing action.