What Kind of Release is this? & Can an effective swing include no deceleration?

[wulsy]

Think you may have got this round the wrong way. Moving your thorax makes the chair go the opposite way. So the rotation of the thorax automatically puts the brakes on the pelvis.

No bud, I understood that. I saw this analogy 5 years ago and originally believed it. To clarify, I can accelerate the thorax in one direction without the chair going in the opposite direction and with the chair going in the same direction. No causality.

Edit: I can of course adhere to the opposite direction claim.

 

[wulsy]

Maybe I'm being naive, but if this is about the idea of acceleration/deceleration as a representation of speeding up or slowing down in layman's terms, then why not just measure the absolute speeds and then derive the accel/decel in terms of speed? IOW, leave the velocity out of it temporarily. Wouldn't that simplify things a little?

 

[art]

Increasingly graphs are being shown re to position, velocity and acceleration. Especially when velocity graphs are shown but discussion is primarily about accelerations, I wonder if this is not a source of confusion for some not quite familiar with the subtle features of these parameters.

I have tried to show, in a very simple way, some characteristics of the data acquisition of position with velocity and acceleration being derived quantities.

Some elementary considerations re acquiring data

Dear mandrin,

Thanks for another VERY worthwhile input to all the folks sincerely seeking 'golf truth'.

I hope you will continue to help them AND ME in pointing out how very complex the science of a golf swing is in reality. As for the potential dynamic challenges with the math and presentations, I have spent time at TPI, and additional sessions with the creator(s) of the TPI 3D system, and am satisfied with the 'cleanliness' of the processed signals and presentations in their 17 page report for each single swing.

Best of all, since the dominant parameter presented is 'angular velocity' of many body elements around a myriad of global and anatomical reference systems, I simply 'integrate' and 'differentiate' the graphs visually, and use the tabular data presented every 0.004 seconds of the calculations to be able to 'see inside the kinematic sequence'.

Any comments regarding this treatment ??

PS, please stay involved as I would like to take this to the next step defining the 'impact' of the centripetal forces developed by the major rotating 'asymmetric' body parts during the explosive downswing, and dearly need your participation.

Sincerely and appreciatively,
art

 

[wulsy]

Not trying to be negative here but isn't our discussing something we can never understand pretty much a waste of time? This thing is so complex even a nobel prize winning physicist would have a problem getting anywhere close to the truth.

You can either believe the scientists or not believe them, but trying to prove them right or wrong is delusional unless you are Good Will Hunting.

 

[Brian Manzella]

You know what's funny?


I had a lesson yesterday with a golfer who needed to slow their hips and transition the the speed into the torso and the clubhead.

Very successful lesson.

 

[Erik_K]

Dear mandrin,

Thanks for another VERY worthwhile input to all the folks sincerely seeking 'golf truth'.

I hope you will continue to help them AND ME in pointing out how very complex the science of a golf swing is in reality. As for the potential dynamic challenges with the math and presentations, I have spent time at TPI, and additional sessions with the creator(s) of the TPI 3D system, and am satisfied with the 'cleanliness' of the processed signals and presentations in their 17 page report for each single swing.

Best of all, since the dominant parameter presented is 'angular velocity' of many body elements around a myriad of global and anatomical reference systems, I simply 'integrate' and 'differentiate' the graphs visually, and use the tabular data presented every 0.004 seconds of the calculations to be able to 'see inside the kinematic sequence'.

Any comments regarding this treatment ??

PS, please stay involved as I would like to take this to the next step defining the 'impact' of the centripetal forces developed by the major rotating 'asymmetric' body parts during the explosive downswing, and dearly need your participation.

Sincerely and appreciatively,
art

I don't see how you can integrate or differentiate anything visually. Either you have an expression in closed form and you apply Calculus or if you have the raw data you can use a numerical technique of some sort. Perhaps this is what you mean by a 'visual' integration/differentiation.

Erik

 

[JEREMY5577]

• World No. 1 Rory McIlroy drives the ball well over 300 yards despite being only 5-foot-9 and 160 pounds. How does he do it? It’s all about the acceleration and deceleration of his hips. McIlroy’s hips rotate and accelerate in the downswing at 719 degrees per second. That’s more than double the average amateur, who averages 350 degrees per second. The key is once they’ve accelerated, they stop quickly, allowing the rest of the upper body and clubhead to catch up. Think about snapping a towel; you flick it then pull back quickly to achieve maximum speed. A great drill to put this into your golf game is imagine a paint brush sticking out of your belt buckle and facing the target. You need to speed up the hips in the downswing and stop them quickly to throw the paint off the brush. Throw the paint off the brush and rip the ball!


--------------------------------------------------------------------------------
This seemed very relevant to post here. I've read he is a friend of the forum. Anyone else see this episode of Martin Hall's show? He also has a great segment on the D-Plane in the same show and Holly Sonders does a fantastic job as well

 

[art]

I don't see how you can integrate or differentiate anything visually. Either you have an expression in closed form and you apply Calculus or if you have the raw data you can use a numerical technique of some sort. Perhaps this is what you mean by a 'visual' integration/differentiation.

Erik

Dear Erik,

If you are presented with a plot of angular velocity versus time, as is the case for much of the 17 page TPI report for a single swing, you simply have to visually/graphically integrate/calculate the area under the curve to get the angular 'position' change over a desired period of time.

Then to arrive/calculate angular acceleration, you simply have to visually determine the 'slope' of the curve at any time.

And the real beauty Erik, is that on the computer, The TPI data also presents an avatar of the golfer that can be viewed from an infinite number of directions, every 0.004 seconds.

You should be able to download a demonstration of 3 swings on Phil Cheetham's AMM site at no cost.

Try it, I think you will like it.

Sincerely.
art

 

[Mike Richardson]

You know what's funny?


I had a lesson yesterday with a golfer who needed to slow their hips and transition the the speed into the torso and the clubhead.

Very successful lesson.

Did you do a video of it?

 

[Erik_K]

OK - that clears it up, Art. You are using a graphical method.

Erik

 

[mandrin]

Dear mandrin,

Thanks for another VERY worthwhile input to all the folks sincerely seeking 'golf truth'.

I hope you will continue to help them AND ME in pointing out how very complex the science of a golf swing is in reality. As for the potential dynamic challenges with the math and presentations, I have spent time at TPI, and additional sessions with the creator(s) of the TPI 3D system, and am satisfied with the 'cleanliness' of the processed signals and presentations in their 17 page report for each single swing.

Best of all, since the dominant parameter presented is 'angular velocity' of many body elements around a myriad of global and anatomical reference systems, I simply 'integrate' and 'differentiate' the graphs visually, and use the tabular data presented every 0.004 seconds of the calculations to be able to 'see inside the kinematic sequence'.

Any comments regarding this treatment ??

PS, please stay involved as I would like to take this to the next step defining the 'impact' of the centripetal forces developed by the major rotating 'asymmetric' body parts during the explosive downswing, and dearly need your participation.

Sincerely and appreciatively,
art

art,
Whatever does the job. After all you are looking for significant information. If it needed too much effort too extract it would probably be not worth looking at. Starting with angular velocity information puts you right in the middle of things requiring only one operation towards either displacement or acceleration. If a method appears “simple” it is not necessarily inadequate. Judgement and intuition can for instance more readily play a significant role.

Just curious - angular velocity is it measured directly or is it rather more likely a derived quantity?

 

[Brian Manzella]

Derived.

 

[James Marshall (Hogan1953)]

Is it the external rotation of the right hip in the transition that allows the hips to accelerate and then decelerate optimally?

If the right hip internally rotates does it tend to continue to accelerate throughout the downswing?

Do the 3D machines differentiate between internal and external rotation of the hips?

 

[ZAP]

OK after reviewing the entire thread again I can say the tables and graphs make sense. It is not a decrease in acceleration but a deceleration or decrease in speed. Some of the double talk had me somewhat confused. (which is not a new thing)(happens nearly every day)(at least I think so)

 

[Brian Manzella]

This is all so simple that even someone with a bad comb-over should be able to get it:

In good players and better, the pelvis ("hips") reach their peak speed WELL BEFORE IMPACT, where after that they are rapidly slowing down by the time of impact.

The torso does something similar.

The left arm does as well.

Why?

That is the only way to get the speed to the clubhead.

If, for some reason the speed gets to the clubhead and the torso or pelvis starts speeding up again, it will REDUCE SPEED somewhat.

We spent two hours on the phone today with one of our scientist, Sasho MacKenzie. A man who has scientific papers published on this sort of stuff.

He says we are absolutely correct in what we are saying, and like always, has smartened us up a bunch more.

How anyone could believe that you go into negative alpha near and through impact (proven in numerous published scientific papers) and think you could do this while you sped up the pelvis, torso, and left arm through impact, without ever slowing them down, is selling something, smoking something, playing games, or worse.

Luckily for golfers, if you are any good at all and aren't too flexible, even trying NOT TO, you'll probably decel in spades anyway in the pelvis at least.

 

[dschultz6072]

It really is as simple as thinking of a trebuchet.

Or maybe even using a stick to smack a dusty rug up on the clothesline.

I guess people will just be stuck in their wormhole until their comb-over whittles away like Big Ern in Kingpin. Then they will be left with nothing and still wonder how guys like this are bombing it past them:

 

[drewyallop]

Dear Erik,

If you are presented with a plot of angular velocity versus time, as is the case for much of the 17 page TPI report for a single swing, you simply have to visually/graphically integrate/calculate the area under the curve to get the angular 'position' change over a desired period of time.

Then to arrive/calculate angular acceleration, you simply have to visually determine the 'slope' of the curve at any time.

And the real beauty Erik, is that on the computer, The TPI data also presents an avatar of the golfer that can be viewed from an infinite number of directions, every 0.004 seconds.

You should be able to download a demonstration of 3 swings on Phil Cheetham's AMM site at no cost.

Try it, I think you will like it.

Sincerely.
art

Right Art. The slope tells all. BTW where does the hip acceleration inflection point happen in the downswing, generally?

 

[Michael Finney]

Art:

"Also, CAUTION here and my final point, the pelvic axis of rotation is constantly changing during the downswing, and therefore the visual points viewed by camera in 2D have a constantly changing 'radius' which has led to WAY TOO MUCH CONFUSION and contention for my liking, and probably all seeking 'truth' versus controversy."

There are three ways to fix the reference frame for 3D motion capture - constant (stripper pole - global), constant (reflect an orientation angle that a body part assumes during a swing....ie. pelvis tilted forward at 25 degrees), or moving - instantaneous screw axis - a new rotational calculation for each new axis of rotation (within reason).....

You would get a different looking graph for each approach on THE SAME SWING.....

So, if you are using global, the pelvis angular velocity will be measured at a "higher rate" as the pelvis "stands up" and draws closer to the global (stripper pole) reference.....nuf said

 

[66er]

Hmmm, grab a golf club in one hand by the grip and without thinking about it, throw the thing as far as you can. What did your hips do? I see no reason for it to be more complicated than that for me. People deny this occurring? The rivalry in golf instruction is far stranger that I could have imagined, safe to say I'm in the right corner.

 

[lia41985]

So, if you are using global, the pelvis angular velocity will be measured at a "higher rate" as the pelvis "stands up" and draws closer to the global (stripper pole) reference.....nuf said

We don't even have to agree to disagree with the "other guys". It's an understandable misunderstanding.