Fore_Thirty,
You wrote-: “I can assure you I am my own, real, independent person and I am not an alias of dubious or Jeff Mann.”
I agree. You are also very smart and knowledgeable and I invite you to join the NGI golf forum at https://newtongolfinstitute.proboards.com/ so that you can contribute and help us better understand the golf swing biomechanics/mechanics of skilled pro golfers.
Jeff,
I don’t doubt at all your sincerity, dedication, and skill. I appreciate hearing about your golfing biography and quest in understanding the swing. My criticisms are restricted to what is being thrown around as science. Perhaps a bit of my biography will help us understand each other.
My undergrad was at Cornell University '91, majoring in electrical engineering. Realizing late that my preference was pure mathematics, I took as many math classes as I could, including real and complex analysis, harmonic analysis, Lebesgue measure and integration, probability theory, set theory and logic, etc. My late uncle was a full professor, specializing in analytic number theory. I learned more advanced mathematics through long conversations with him throughout my twenties. Along with my mathematics and engineering background, I’ve taken and studied enough physics to hold my own. I bring this up only so you can see where I’m coming from.
As I’m sure you know on an intimate level, any human motion is complicated, and the golf swing is no exception. No simple physical model with pendulums and gears and pulleys and springs will capture fully what’s happening. Moreover, certain exceptional people have performed physically amazing feats throughout history. No sane person would say that in doing so they defy the laws of physics, even if it may seem as though they do. It may seem impossible to you that someone skilled in a certain technique can accelerate a club all the way to impact, but you wouldn’t deny a robot can be built to do so. Would you? You wouldn’t deny that by starting slowly from P3, acceleration can be maintained to impact. Would you? You still may not believe it’s possible for a human making a full swing with sufficient club head speed at impact to play serious golf can do so, but it’s not at all like claiming one can fly by flapping one’s arms. It’s certainly not clearly impossible. Citing the basic laws of physics won’t help either. As we noted, these are complicated movements. And robots can certainly perform this feat.
Since there’s no law of physics that’s being defied by the claim that accelerating to impact is possible, we must turn away from theoretical arguments and look for other means. Indeed, you have looked to data. That brings us to my next criticism.
Broadly speaking, scientists use data in two ways. One is to test a theoretical result. Calculations are made from a theory, and they are compared against data collected by measurement. But there’s no theory being tested in that video, so let’s move on to the other use of data. Scientists also use data from observations to play with. That is, to gain insights to better understand and possibly, after much effort, make a theory that can then be tested. That is the stage we’re in. And that’s where my objections lie.
You can’t draw conclusions from the same data you used to make your hypothesis. You’re looking at data from certain swings, and then using that same data to make bold assertions. “We tested all these pros who don’t accelerate to impact, therefore it’s not possible to do so.”
This is not science. It’s marketing. (The pharmaceutical industry suffers from the same diseased mentality!) It may still be useful, and it may be profitable, but it’s not science. There’s another danger inherent in using data in this way. While we should strive to measure whatever we can, there’s a pernicious tendency to overweigh the importance of what we can easily measure and undervalue what we can’t or at present haven’t.
I also know that no matter what I post its going to be excuses about how it doesn’t meet whatever standard you want it to meet and the goal post is going to be raised.
You’re making the claim that it’s science, it’s physics. It’s not. Can it lead to good science? Sure. Is it worthwhile making these observations and looking at the data? Yes. But that’s not what you’re doing. You’re claiming that it establishes scientific facts about accelerating to impact. It doesn’t. Pointing this out is not an excuse or a shifting of goalposts.
If you haven’t already done so, I recommend reading Richard Feynman’s essay/commencement address about what he called cargo cult science. It’s very well known, and quite funny. http://calteches.library.caltech.edu/51/2/CargoCult.pdf
As for pivot stalling, it means just what it implies, the rotation of the core, of the hips/torso/shoulders, is slowing down or stopping near impact. You don’t even need fancy equipment to see this. Just look at video from a down-the-line view. Step through the video frame by frame. Is the pivot of the core moving (rotating) significantly in each frame from P3 to P4? If so then there’s no pivot stall. If the pivot slows down dramatically or stops, there’s a pivot stall. Even though that video you posted was from a caddy view, you can see that the core slowed down to let the arms catch up. Indeed, that’s what you describe as “evidence” of it being impossible to accelerate to impact. Hogan clearly didn’t pivot stall. ABS teaches a very gradual speed increase from the top to P3 (which is not, as you stated, what that pro is doing) and then pouring it on after P3 using mainly a vicious torso rotation. It’s a very different technique. That’s why the observation and data from that video you posted have nothing to say on whether it’s possible for an ABS type technique to accelerate all the way to impact.
At the risk of making this already too long post even longer, I want to end it on a constructive note. What would be an interesting and useful application of the GEARS data is to see, among other things, how far into the downswing players maintain acceleration. How do different techniques effect this? Is there even a correlation? That is, we can use the proverbial lamppost for its intended purpose, illumination, rather than how the drunkard uses it, for support (of prior biases).
Hanisch,
You asked-: “It may seem impossible to you that someone skilled in a certain technique can accelerate a club all the way to impact, but you wouldn’t deny a robot can be built to do so. Would you? You wouldn’t deny that by starting slowly from P3, acceleration can be maintained to impact. Would you?”
I think that it is impossible for a golf robot machine or a human golfer to accelerate the clubhead all the way to impact using the “holding shaft flex” technique where the peripheral clubshaft remains bent back all the way to impact - if the degree of clubhead lag was greater than 90 degrees at the start of the downswing and if the lead arm is positioned at the 10:30 o’clock position at the end-backswing time point.
When you look at John performing his “holding shaft flex” technique in his latest video, he starts off with his lead arm at the 7 o’clock position and with virtually no clubhead lag, and then he simply applies enough accelerating force with his hands to accelerate the club into-and-through impact. Under those conditions, the peripheral clubshaft will be bend backwards (implying the presence of lag tension) all the way to impact and beyond.
However, look at what happens in his “real life” golf swing action when he starts with his lead arm at the 10:30 o’clock position and when he has >90 degrees of clubhead lag.
At the P5.5 position (image 2), note that he still has ~90 degrees of clubhead lag and lag tension exists (note that the peripheral clubshaft is bent backwards). Note how much clubhead lag is lost between P5.5 (image 2) and P6.5 (image 3) due to a lead wrist uncocking action that is associated with a partial trail arm straightening action, and note that the peripheral clubshaft is bent forwards at P6.5 due to the speed of the club release phenomenon. John cannot prevent that club release phenomenon which works according to the laws of physics. You are not taking that “fact” into account.
Jeff.
Ayersjj wrote-: “Same old same old. Nauseating.”
I agree that it is a nauseating “same old same old” fact that many ABS groupies will never mentally engage with opinions that disprove their ideology.
Jeff.
The fact that launch monitors such as GC Quad, Trackman, Eye XO, and other high end devices do not account for the mass of the club head is not a limitation. The mass of the club head is irrelevant to what they measure and report.
These machines don’t calculate club head speed from ball speed. They measure club head speed and ball speed. They measure them directly and independently. There are many studies using these devices in many sports and in non-sports applications which have proved the reliability and validity of their measurements.
Whether the mass of the club is heavy or light, the speed of the ball is the speed of the ball, and the speed of the club is the speed of the club, and both are measured.
I’m not disputing that club head mass or other features of clubs such as lie angle aren’t important in teaching or learning golf. I’m not a golf expert. And I have heard many teachers speak out against teaching someone entirely off launch monitor numbers. But that is a separate issue from what launch monitors actually do.
I don’t understand this to be true… certainly not with “Trackman” which is or was the most popular machine for a long time now. It does not measure clubhead speed independently. It’s only measures ball speed and then makes assumptions about clubhead speed. From everyone I have talked to about this that should know… this is how it apparently works. I can’t speak for the other machines.
It would be great for Mr. Erickson or Mr. Hughes or someone else who teaches ABS technique to get on GEARS and see what is actually happening in their swings. GEARS measures the body and the club simultaneously, as I’m sure most people know by now. We don’t need to debate or argue what’s possible or what isn’t, when we can just look and measure what’s actually happening.
I am pretty sure someone offered to donate GEARS time to study the ABS swing.
What is the main argument going on here? Is it whether hitting (pivot acceleration and shaft flex maintained) or swinging (shaft deflected forward at impact) is better? Is it whether hitting (as described above) is possible or not?
I don’t think posting GEARS data is an argument from authority. It’s just presenting data.
I’m not making any judgement about what the best swing is, nor am I in any way disputing what anyone says about the soundness of the ABS hitting swing. But GEARS data show, both in most individual swings and in the tour average swing, that everything in the body has negative acceleration through the impact zone; only the club head has a positive acceleration. The hands, arms, ribcage, and pelvis all have positive acceleration EARLY in the downswing. It then changes to a negative acceleration, at some point around when the lead arm is parallel to the ground. The sequence is clearly that the body parts accelerate in the first part of the downswing, then begin to slow down, while the club head continues to speed up through into impact.
I’m not claiming that there aren’t some players baked into that average that do it differently, but if they do, we should be able to see it. I haven’t looked at all the players. I paid for a GEARS license so I could look at the data, and thus far I haven’t found a tour player who has the shaft bent back at impact on a driver swing. Not saying there isn’t one.
Can we agree that what is measured in GEARS is better quality data than what is inferred from looking at still photos or video sequences? Or maybe I’m missing something.
So now we have yet another anonymous poster @86General of whom we know nothing of his credentials nor playing experience yet comes on to laud the benefits of GEARS.
@86General @Dubious @Fore_Thirty please when you post include your professional accomplishments both in the areas of physics and biomechanics and in your golfing careers. Also, when you present an opinion please include any peer-reviewed studies conducted to back up your opinion. Without this then I can only take what you say as what it is - an opinion.
The list is growing. @Dubious @JeffMann high handicappers not so happy swingers projecting misery as online trolls. They have another website nobody here cares about. I guess they are talking to themselves over there and feeling lonely.
@JeffMann has been puking 
up bullshiat here for 13 years!
86general,
You wrote-: “But GEARS data show, both in most individual swings and in the tour average swing, that everything in the body has negative acceleration through the impact zone; only the club head has a positive acceleration. The hands, arms, ribcage, and pelvis all have positive acceleration EARLY in the downswing. It then changes to a negative acceleration, at some point around when the lead arm is parallel to the ground. The sequence is clearly that the body parts accelerate in the first part of the downswing, then begin to slow down, while the club head continues to speed up through into impact.”
Where is your evidence that the clubhead continues to accelerate into impact in a pro golfer’s driver swing? This issue has been scientifically studied and it has been shown that clubhead speed reaches its maximum speed at about 90% of the downswing phase in the studied driver swings of PGA/LPGA tour golfers and slows slightly just before impact.
See - https://www.researchgate.net/publication/5292347_Swing_Kinematics_for_Male_and_Female_Pro_Golfers
Jeff.
It’s from the GEARS animation of the tour average swing. As you scroll through the late downswing, in the impact zone, the club head speed goes up.
This screenshot is from the tour average swing. It shows the club head about a foot from impact, and club head speed is 112-ish. It hits the ball at 114. This is a still image, but in GEARS you can scroll back and forth, and the point of maximum club head speed for this average swing is either at the moment of impact or milliseconds prior to impact.
I’m not trying to upset anyone’s apple cart. I don’t have any physics credentials. I’m a physician, my subspecialty is neuropathology. I diagnose tumors and so forth all day. I’m an above average recreational golfer statistically speaking but I’m not nor have I ever claimed to be a golf expert, ball striking expert, or swing analyst. I’m just pointing out what has been collected as data on GEARS.
As to the study you posted and the difference, I suppose it could be attributable to different methods of measuring club head speed.
My point wasn’t that it was significant per se that the club head accelerated into impact. My point was that for the tour average swing, the body had a NEGATIVE acceleration into impact, and in fact begins de-accelerating long before impact. That’s what GEARS measures.
Maybe someone has some explanation for it or can explain why they think the GEARS data is somehow inaccurate. Again, posting totally agnostic here.
I have no idea who Dubious or anyone else is. I got interested in this forum because I love golf and like reading and talking about the swing, that’s all.
Finally…someone asked for references. I don’t think they are really necessary for the point I was making, which was to simply demonstrate GEARS data. But the question piqued my interest and I did a very quick literature search. Multiple studies have measured the kinematic sequence of elite golf swings (and baseball swings, and similar things in other sports). I didn’t read them all 
nor am I claiming to be an expert…but, here is a link to an article on the kinematic sequence of elite golfers in which it demonstrated that the pelvis reaches its peak angular acceleration before impact. The peak was something like 100ms before impact in the elite golfer group, which would be anywhere from 1/2 or 1/4 of the downswing interval. So the hips are decelerating for at least half of the downswing, according to this study.
That is unequivocally not true. Trackman and Flightscope (radar systems) as well as Foresight (camera system) are directly measuring the movement of the club and the movement of the ball. The clubhead speed is measured and the ball speed is measured. The smash factor is then calculated because that is a math based equation based on those two speed measurements.
There are, however, discrepancies between the systems when it comes to clubhead speed. This is due to when the measurement is reported. Trackman reports at maximum compression and Flightscope and Foresight report upon first touch. So it’s possible to hit on Flightscope and see your clubhead speed drop a few MPH if you then go hit on a Trackman. It’s not a flaw, it just requires knowing exactly what each machine is doing and when its measuring.
Jeff,
John cannot prevent that club release phenomenon which works according to the laws of physics. You are not taking that “fact” into account.
Which “laws of physics” do think his claim is violating. Please state the exact law or laws. For example, does his claim violate Newton’s second law of motion that force is equal to the first derivative of momentum with respect to time? His law of gravity? Einstein’s law of gravity (general relativity)? Maxwell’s equations? Dirac’s? The second law of thermodynamics? Which laws of physics? Let’s be precise.
Do you really think a robot can’t be built with a motor that turns with angular acceleration (nonuniform angular velocity) with an arm attached such that the arm also moves with an angular acceleration? If your hangup is doing so with a right angle “club head lag,” have you considered that the “hinge” need not be free flowing, reacting only to momentum? That is, it can be motorized to either assist or resist being opened or closed.
Note, the shaft straightening radially due to the centripetal force acting against the club head wanting to go in a straight line does not contradict that it can still have angular acceleration.
Also, I very much appreciate reading your posts and hope you continue to do so, but please use ABS terminology when posting here. Wouldn’t you want those who post on your forum to respect your terminology?
Others may be arguing which is “better,” and that’s a discussion worth having, provided we are clear as to what we mean by better. But that has nothing to do with my argument. I’m criticizing the assertion that the laws of physics are being violated, and specifically that GEARS data “proves” this.
I don’t think posting GEARS data is an argument from authority. It’s just presenting data.
I never said that presenting GEARS data is an argument from authority. I said that name dropping supposed experts is an argument from authority.
Again, I’m not anti GEARS or any other attempt to measure the golf swing. Far from it. I’m against cargo cult science. For instance, I’m criticizing drawing conclusions using the same data from which hypotheses are formed.
