August 28th, 2013, 05:29 PM
What's wrong with this picture??
In a Facebook thread, this gif of Johnny Miller was posted.
The yellow lines suggest little if any deceleration of the hips; perhaps, even, some acceleration in the last frame. In response, Dr. Kwon posted the following:
How does Dr. Kwon know "it is not true"? Certainly he can't tell from a single gif of four images taken from just one view??
To make such a claim as fact instead of opinion, wouldn't he had to have measured golfers with the "second fire" look of Miller and other elite golfers? And wouldn't he need to have quantitative data to support his conclusion? If he has the data, then why is he looking for players with a "second fire" to measure?? And if he doesn't have the data, why is he making statements of opinion as if they are fact??
Kel has published lists of PGA and LPGA players that "second fire" and those that stall. Don't the biomechanists have some of each in their data bases? Why don't they just do the analysis with what they have? Wouldn't someone serious about understanding the "second fire" be doing that already?
August 29th, 2013, 09:42 AM
In their extremely narrow definition, rotation around the fixed rigid axis of the spine, this is not rotation. But the spine is not rigid nor is it fixed. Nor does it make sense to any golfer or athlete. But is sure makes for a simple, easy to sell model of the golf swing that only THEY understand and therefore they are the only experts (unless you are Manwithsmartfriends).
In a way this is more about human behavior, ego and bias vs. scientists looking for the truth.
August 29th, 2013, 10:09 AM
Its quite obvious whats going on...its a case of Manz using Kwon as a Shields to hide his Finneyite knowledge.
August 29th, 2013, 10:25 AM
Originally Posted by Kelvin
That sums things up just about as well as anything I've seen!
August 29th, 2013, 01:08 PM
This reminds me of an old academic joke. A dairy farmer who, in a fit of desperation over the fact that his cows won’t give enough milk, consults a theoretical physicist about the problem. The physicist listens to him, asks a few questions, and then says he’ll take the assignment. A few weeks later, he calls up the farmer, and says “I’ve got the answer.” They arrange for him to give a presentation of his solution to the milk shortage.
When the day for the presentation arrives, he begins his talk by saying, “First, we assume a spherical cow of uniform density …”
August 29th, 2013, 06:43 PM
Isn't this easily resolved by sending one of your students to be tested as Kwon suggests?
Originally Posted by Jeff Martin
August 29th, 2013, 09:51 PM
Originally Posted by drewyallop
No. How would testing just one swing in isolation "resolve" anything? The question is "what movements comprise the second fire and how do they differ quantitatively from a player that stalls?" Several players of both type need to be analyzed. It has been claimed by the "scientists" that the necessary data already resides in existing data bases. Kwon, et al should just get on with it.
August 31st, 2013, 10:51 PM
It would be a great idea. Clearly there are some folks here who believe a "second fire" exists and can see it on 2D. Choose one person to do a 3D collection - video can be taken at the time to make sure that the swing represents (at least that golfer's) second fire. All it takes is one diamond to prove that diamonds exist.
May 8th, 2014, 07:35 PM
I got a hold of some TPI data documenting the second fire and did the work for them...
Alas, my plea in bold above fell on deaf ears...
Originally Posted by Jeff Martin
However, recently I learned that anyone, so long as they register with TPI, can download the TPI 3D Pro Analyzer software that is used to prepare analyses from player data collected from their AMM sensor-based system. The software comes with the data for three unidentified "demo pros", so you are free to prepare whatever analyses you want with them. The link is here:
Kel looked at the 3D renderings of the three demo pros and quickly surmised that they are, respectively, Steve Elkington, Ernie Els and Arron Oberholser. Although Elk and Ernie are major champions, none of the three "demo pros" have a "Gold Medal" swing. However, by a welcome turn of fortune, I have obtained the data for a "Gold Medalist". In order to protect the guilty, I won't name the Gold Medal player.
During the second fire debate last summer, Phil Cheetham made some interesting posts on Facebook. Here are two:
Here is a video of Gary Woodland where Ian Baker Finch describes the "lift" Cheetham is referring to, what we would call the second fire:
Accepting Cheetham's definition of second fire, the graphs he posted seemed like a good place to start to quantify the differences between an elite player with a strong second fire and a player with none. What I found is that Arron Oberholser (Pro3) had the weakest hip and knee extension relative to our elite player (note that I had to adjust the sizes so the left hand vertical scales matched). The positive values in the graph below reflect how much the lead hip, knee and ankle are flexed. The downward sloping lines represent the three joints extending in the second half of the downswing, during the second fire. The elite player (on the left) extended the lead hip about 23 degrees, Arron (Pro3 on the right) extends only about 8 degrees: clearly, Arron isn't firing the lead glute with very much, if any, intensity. Similarly, Arron's lead knee extended 17 degrees to the elite player's 29. Someone isn't using the "fearsome foursome"!
Compared to Woodland and other elites, Oberholser's downswing is powered by one continuous motion of the lower body, with no squat or second fire of the hips and knees in the second half of the downswing. Although he has nice rotation and gets the hips and chest well open at impact, his lower body has a languid quality you don't see in the elites. Not surprisingly, Arron's clubhead speed at 105mph was the slowest of the group; our elite player's was the highest at 118mph.
Since Phil Cheetham said that "lift" will add power, let's compare the lift of the pelvis and thorax of the two players. The top graph shows the amount of lift in inches, the bottom graph shows the speed of the lift in mph.
This is quite a dramatic difference: the elite player's pelvis and thorax elevated at an identical pace, whereas, despite a modest rise in the pelvis, Oberholser's thorax actually dipped: Oberholser's swing isn't generating any lift in the second half of the downswing. By Cheetham's definition, no second fire.
One thing to note about the elite player's pelvis and thorax is that they are both accelerating upward, in the second half of the downswing, just as the angular rotation, as reported by TPI, is decelerating:
In Oberholser's swing, there is no second "bout" of acceleration. In a lab that measures ground reaction forces, one would expect this vertical lift to create a vertical ground reaction force, in addition to the ground reaction forces created by the body's rotation through the feet. If one can strip out the forces created by the swinging arms and club, as Doug Marsh recommends in his paper on the distribution of mass and pressure, I would expect to see two peaks in the cumulative ground reaction forces created by the body's movements.
Another thing I noticed in Arron's swing is the absence of the pelvis thrust towards the target line that we see in elites, as Kelvin documented in this article:
Here are the pelvic thrust graphs for Arron and our elite player. Positive values reflect movement towards the target line, negative values are movements away from the target line. As we can see, this is another area of dramatic difference between an elite and a non-elite. Arron is pushing his pelvis away from the target line throughout most of the downswing, whereas Gary's pelvis moves rapidly towards the target line in the second half of the the downswing, a movement which, when combined with lateral bend, facilitates rotation in the second half of the downswing.
To test these findings, I also have a bootlegged copy of some of Jamie Sadlowki's TPI graphs. Here are the "standard" TPI pelvis and thorax graphs for Jamie:
The blue lines reflect pelvic and thorax lift, and follow the elite player's pattern very closely. The green line in the top graph represents pelvic thrust, and also mimic's the elite player's movements.
What is surprising, and disturbing, is many of analyses I have prepared do not appear in the TPI reports or even in the many "standard graphs" contained in the TPI software: they had to be created on a custom basis. Despite "knowing" that the lift of the thorax and pelvis adds power, the movements of the lead hip, knee and ankle that create the lift are not in the reports or even a standard graph. This just reinforces the belief that the biomechanists as a group remain wedded to the kinetic sequence model and ignore the contributions of the second fire.
One final note. In Cheetham's first post I pasted above, he says this about the lead hip and knee graph of Pro2 (Ernie Els):
But look at the elite player's lead hip and knee graph: the extension continues through impact:
And, how do Ernie's and the elite player's pelvic and thorax lift compare?
Because of his extreme jump, Ernie gets more lift than the elite player, but the speed of Ernie's lift peaks well before impact and fallis to almost zero, so the vertical ground force created by the lift will presumably be dissipating before impact. There is a reason to study the movements of the elites, Phil!!!
May 9th, 2014, 12:37 PM
Great posts, Jeff and Kelvin!
May 9th, 2014, 01:39 PM
For those wanting a refresher on the second fire, read this article:
Kel discusses pelvic lift in this section:
May 9th, 2014, 06:06 PM
You can find a great face on of hogan in the hardcase from Texas stuff . He was way past his prime as well . Belt buckle goes way forward and way up
May 10th, 2014, 09:12 AM
Some more extensive analysis...
I have been trying to explain the "second fire" concept to Dr. Kwon, without much luck. I guess I'd forgotten how many pieces there are; of course, they are all outlined in Kelvin's articles, but Dr. Kwon doesn't seem to have read any of them. So here we will explore some more TPI data that illustrates the difference between an "elite" second fire, and something else.
Let's start when the second fire is initiated. Here is our Gold Medal player at the point where the glutes begin to fire and extend the hips (the red line is lead hip flexion/extension, in degrees):
We can see that, at this point, his knees are separated, reflecting dual external rotation of the hips and dual abduction of the thighs. Significantly, his reaches maximum separation of the knees just as he initiates the firing of his glutes (the red line is the separation of the knees, in inches).
Let's compare these positions to the others. Pro1 (Elk):
Elk's knees have already started to close at this point, because he has not held the right knee in place, and the right hip is going into early internal rotation.
Here is Ernie (Pro2):
Ernie's knees follow a completely different pattern: the knees close significantly from address until well into the downswing then separate. We don't see much in the way of dual ER or dual abduction.
Although Arron has almost no second fire, his pattern for these two movements are the closest to our elite player. But, as we saw above, he has almost no "lift" in the second half of the downswing. Let's look at each player's "lift":
Ernie, with his big jump in the downswing, gets the most lift; Oberholser, who, as you recall, does not allow his pelvis to move towards the target line, generates nearly zero lift. Here is the pelvic thrust for each player (positive is towards the target line, negative away, in inches):
Ernie, with the most lift from his jump, moves the pelvis closest to the target line, while Arron, who keeps his "butt against the wall" and beautifully "maintains his tush line", gets no lift.
Now let's look at the speed of the lift (in mph, the numbers on the bottom of each graph indicate the speed at impact):
These charts are very revealing. Of the four, the elite player is the only one with the thorax lifting significantly at impact: Elk's thorax has stopped lifting, Els' is barely lifting at 0.1mph and Oberholser's is descending at 0.5mph. Not going to generate much parametric acceleration doing that! Similar pattern with the pelvis: elite rising the fastest at 0.8mph, then Ernie at 0.5mph, Elk at 0.4mph and Oberholser declining at 0.1mph.
Although each player has one or more moves in common with the elite player, none have all of his moves, and none achieve the same result.
Now let's compare body positions at impact (rotation in degrees, positive is towards the target, negative away; the numbers at the bottom of each graph reflect the degrees open at impact):
With his slide, Elk has the minimum pelvic rotation. Despite his jump, Ernie gets pelvic rotation similar to our elite swinger. As mentioned in the post above, Arron gets his pelvis and thorax well open at impact, the most of the group.
In the next post, we'll look at the rotational velocities and the influence of engaging the spine engine through right side lateral bend.
May 10th, 2014, 11:18 AM
May 10th, 2014, 12:56 PM
Before we look at the rotational velocities of the pelvis and thorax, let's look first at each player's right side lateral bend. As you will recall, right side lateral bend engages the spine engine and facilitates rotation. Let's see how the numbers stack up.
Below are the spine side bend graphs; TPI defines spine side bend as the difference in angle between the pelvis and thorax, expressed in degrees, with positive values reflecting trail side bend, negative lead side bend. We would expect players with the best rotation to engage right side lateral bend early, and have more of it throughout the downswing and at impact (the numbers at the bottom of each graph indicate the amount of right side lateral bend at impact).
Sure enough, our elite player and Arron, the two with the most rotation at impact, start right side lateral bend earlier (when the red line crosses the horizontal axis, going from negative to positive) and have more of it during the downswing and at impact than Elk or Ernie. Arron, with the most rotation at impact, also has the most right side lateral bend.
Let's see how right side lateral bend correlates with rotational velocity (the green vertical line marks where the pelvic rotational velocity peaks):
Once again, some very interesting results. First, both the elite player and Arron have higher rotational velocities at impact than Ernie, even though Ernie had the highest peak velocities of the four. Those three players reached peak thorax velocities at about the same time: Ernie's pelvic velocity peaked at 0.10 seconds before impact and his thorax velocity peaked 0.08 seconds before impact; the elite player and Arron reached peak velocities for both the pelvis and thorax at 0.08 seconds before impact. Elk's stall shows up in this data: his pelvis reaches peak velocity 0.12 seconds before impact, and the thorax peaks at 0.87 seconds before impact.
Significantly, the elite player retained the highest percentage of peak velocity at impact, and Arron the next highest. Although all players experienced deceleration, the players who started lateral bend early rotated open the most by impact and retained a higher percentage of their peak velocity.
Note that the elite player and Arron had their pelvic and thorax velocities peak simultaneously: no kinetic sequence with these two. How could you, if the upper and lower body are locked together and rotating as a unit? By doing so, the pelvis reached peak velocity later in the downswing than Ernie or Elk.
One last thing to look at. Is their a correlation between rotation of the body and rate of closure? An objective of the elite body movements is to accommodate a very stable release style. Let's look at what is called handle axial velocity at impact: the rate of rotation along the shaft, expressed in degrees per second, captured from a sensor just below the grip:
The players with the best rotation have the lowest rate of axial rotation. How about tendency to flip (early extension of the lead wrist and flexion of the trail wrist)?: positive values reflect flexion (bowed), negative values are in extension (bent), in degrees. The numbers at the bottom of the graphs are at impact:
Again, the elite player, with the highest rotational velocity at impact, has the most left wrist flexion and right wrist extension at impact.
So, where does this leave us? Of the four players, our Gold Medalist possesses more of the optimal movements than any of the others. He also has the highest clubhead speed of the group and is ranked by Richie as an elite driver of the golf ball.
He engages the spine engine early with right side lateral bend; achieves the squat (dual external rotation of the hips and dual abduction of the thighs), setting up a strong second fire; aggressively fires the glutes in the downswing, allows his pelvis to move towards the target line and is still lifting through impact; his pelvic rotational velocity peaks later, as well as simultaneously with his thorax rotational velocity (no kinetic sequence), and they both decrease by the smallest percentage between their peak and impact, resulting in the highest rotational velocities at impact. The elite player also has a stable release, with significantly lower axial velocity than major champions Elk and Ernie, as well as the most left wrist flexion and right wrist extension at impact.
Arron makes good use of the spine engine and rotates well, but lacks speed, perhaps because of a non-existent second fire. I wonder if he was coached to keep his pelvis back and "maintain the tush line"? His release is stable axially, but gets close to a flip.
Elk slides, lateral bends late and stalls his pelvis, with the worst rotation of the group. Also, he has the second highest rate of closure, as reflected in his handle axial velocity, in the group.
Ernie generates a lot of speed, both rotational and vertically, more than any other player, but, by impact, he loses half of his pelvic rotational velocity, a third of his thorax rotational velocity and all of his vertical velocity. That results in a clubhead speed 9mph lower than our elite player. I wonder if he was ever coached to "slam on the brakes"? He also has the highest rate of closure: I can remember watching his coach at the time, Robert Baker, on the Golf Channel years ago, demonstrating a "training" exercise where the player swung the arms back and forth, from waist high to waist high, while rotating the forearms open and closed as fast as possible.
As you all know, I have covered just a fraction of the movements that are part of an elite swing, and I have put it together somewhat hastily, so there will inevitably be mistakes. Nevertheless, I hope this analysis makes clear that playing the PGA tour or winning major championships is not indicative of optimal body movements. Yes, our elite player is very athletic, but Elk and Ernie are both very big men and don't get out of their body's nearly what they are capable of. You can see it in video or quantify it with a 3D system, but, either way, the truth is the same: elite swingers do it a different way, a lot of different ways!