hitting against a firm left side?? (SUBJECT of a NEW! Manzella YouTube!)

[nmgolfer]

Not exactly; his measurements, in fact, confirm Nesbit's work. See my post immediately above.

The angular velocity refers to the club not the "arm triangle" or anything else... anyway... have a look at at the swings...

http://www.jssm.org/vol4/n4/17/f2.gif

You may have to pull that into somthing where you can enlarge it to see that: the space between dots for the male golfer 1(scratch) hands near impact ARE NOT decreasing.

 

[mandrin]

You are incorrigible... you've demonstrated little understanding of dynamics (verging on total incompetence) and now you've taken to excoriating (sans details as always which is your motis operandi) a published professor of mechanical engineering who holds a doctorate in the field.... simply because his very detailed results contradict your own simpleton study. What a joke. Now its all about your "reputation"... science be damned isn't in mandrin.... Everything... fine so long as everyone's singing Tammy Wynette's tune re.. standing by her mandrin.

nmgolfer,
You are complimentary as usual, it almost gets a routine. It seems that you might have some problems, why not look for help. They can’t be solved on a golf forum.

 

[Brian Manzella]

NM<

Why are you ignoring me...on my forum?

 

[nmgolfer]

You think I favor Mandrin, you are correct, he has contributed to this site over a long period of time.

I have little doubt you are not on my site to LEARN anything from me.

So.....why are you here?

Because I thought this was a truth seeking science friendly forum and because one of your staunchest supporters asked me to join in the discussion. You are correct that I will never take a lesson from you ( or anyone else for that matter) but you are mistaken if you think I do not respect what you as a person or what you believe to be true about the golf swing. My only agenda is to set straight misconceptions (using science) as I encounter them and to continue to learn all I can. I will leave and not come back if that is your preference Brian.

 

[Brian Manzella]

Truth seeking welcome...

I have no problem with SCIENCE.

As a matter of fact, this winter, me and two of my staff instructors, are going to see some golf's finest.

Dr. Aaron Zick, Tom Wishon, a couple of the major equipmet companies with research departments, etc.

I'll get the science, make SENSE out of it for all, and end this back and forth, once and for all.

The fact that you and some others won't QUIT taking about "when the chain doesn't stop" for some good players, when I know for sure that it does for all, drives me batty.

 

[nmgolfer]

That's great Brian... Zicks acoustic swing sensor sounds cool. He's an instrumentation specialist I believe. I strongly suggest you schedule a visit with Nesbit if possible. If nothing else, find out when his office hours are and pretent you're that student who never comes to class (just kidding). Anyway... a mechanical engineer like him will have a different perspective than a that math teacher or intrumentation guy. I'm not sure what wishon's qualifications are... but I respect his willingness to admit having been wrong (like yourself) and I know he's been attempting to learn all he can. Southern Colorado is also nice but bring your skis that time of year.

I don't talk about "the chain"... in fact I don't know what that is... anyway think about it and PM me with your decision. When/IF Mandrin stops with the insults I'll be happy to do the same but like yourself, I'm nobody's doormat.

 

[Brian Manzella]

Tell you what...

Nm,

Go learn about the "chain."

Go to Titleist or TaylorMade or anyone with one of the higher-end systems they use.

Our own Damon Lucas is investing in one of the ones TaylorMade uses. We will PUBLISH everything we learn.

But we might charge for it.

Where else did you hear of the SPOT in the swing where the DEGREES of axis tilt becomes the SAME DEGREES as the amout of OPEN Shoulders?

Right cha, from yours truly.

I call it the "Manzella Rule."

 

[JeffM]

Brian

Please don't encourage nmgolfer not to contribute to your forum. He has an unique perspective, and if you value the "truth", it always helps to read counter-arguments. Even if you prefer Mandrin's explanations, the scientific truth is always best served if any SINGLE person's scientific explanation is open to criticism. My own opinions on the golf swing are not written in stone, and my own opinions require constant modification in the face of a good counterargument. Your forum is unique in the sense that the quality of the counterarguments are deeply thoughtful. I only wish that nmgolfer and mandrin would quit their ad hominum attacks and simply present their unique thoughts/opinions regarding golf mechanics.

Reagrding the kinetic chain, it would be wonderful if you could post the results of a study performed on a good golfer - using one of those high-end systems.

Jeff.

 

[JeffM]

No they don't, your depiction of the decline in angular velocity in Tiger's swing confirms Nesbit's observation:

"The maximum swing angular velocity consistently occurred 0.025 seconds before impact for the scratch golfer..."

It is also consistent with his findings regarding linear velocity:

"Generally, the maximum grip velocity was reached just before impact and remained constant or decreased slightly through impact."

Instead of doggedly referring to Figure 4 (which shows linear velocity), why don't you cut and paste Figure 7 from page 10, which shows the angular velocity declining before impact? What's wrong with acknowledging the truth?

--------------------------------
My spline points traced the linear movement of the conjoined hand unit in Tiger Woods swing. It certainly is NOT a measure of angular acceleration. Angular acceleration refers to the clubshaft, and NOT the hands, and I made NO attempt to measure the angular acceleration of the clubshaft.

Jeff.

 

[jeffy]

--------------------------------
My spline points traced the linear movement of the conjoined hand unit in Tiger Woods swing. It certainly is NOT a measure of angular acceleration. Angular acceleration refers to the clubshaft, and NOT the hands, and I made NO attempt to measure the angular acceleration of the clubshaft.

Jeff.

I made no mention of angular acceleration. Get your conjoined hands off your unit and pay attention.

 

[jeffy]

The angular velocity refers to the club not the "arm triangle" or anything else... anyway... have a look at at the swings...

Then explain to me this passage:

"Figures 7, 8, and 9 illustrate the alpha component of the angular velocity, angular acceleration, and torque applied to the grip respectively for the four golfers."

BTW, I was unable to view the link.

 

[jmessner]

Following Jeff's lead on showing hand speed, I took this swing of Tiger's that Brian has shown before (I think it was filmed around 1000fps) and drew splines at approx. .0075 sec intervals. Click the picture to get a bigger view, but from this perspective it looks like Tiger's hands slow down the last the last .03 sec or so just prior to impact.

The difference in my splines is that I use the butt end of the club (heel pad of left hand) as the hinge point, which seems like a more natural hinge point to me rather than the middle of the hands somewhere. It also eliminates including any of the angular speed of the shaft. I still don't know where Nesbit measured his hand speed - I couldn't find it in his article.

 

[JeffM]

jmessner

Very interesting!

Your attempt seems to be more accurate than my cruder attempt, and it seems to show that the hands maintain their speed virtually to the point of impact.

By the way, I also used the butt end of the club to place my spline points, but the butt end disappears when the left wrist uncocks/left forearm supinates in the last phase of the downswing. I then placed the spline points along the outer border of the back of the left hand. Could that produce a significant error? How did you resolve where to place spline points in the last phase of the downswing - just prior to impact?

Jeff.

 

[jmessner]

Hi Jeff-

I had to estimate as the hand rolls, but it was fairly easy for me especially if you can sequence the video a few times before you mark the position. But, it was obvious that the butt end slows just before impact if you watch the video. It may be a consistent speed just prior to impact but it would not resemble the graph of hand speed that Nesbit shows - it would almost be flipped over. The "hand" speed at impact is about half of that of the earlier part of the downswing. Brian's point of about low frame rates is good in that this would likely be missed at 30 or 60 fps.

Jay

 

[hcw]

Hinge point

The difference in my splines is that I use the butt end of the club (heel pad of left hand) as the hinge point, which seems like a more natural hinge point to me rather than the middle of the hands somewhere.

If you hold a club in front of you clubhead up toward the sky and then pivot right and left you will see that the hinge/pivot point that doesn't move right or left is where your hands meet. Using the heel pad/butt end of the club will cause an artifact as it "reverses" as the hands turn over.

-hcw

 

[JeffM]

Jay

Doesn't hcw bring up a pertinent point? The butt end of the club essentially "reverses" at the point of impact, and measuring it may suggest a greater degree of slowing, that doesn't reflect the "true" amount of slowing of the conjoined hand unit.

Either way, your results certainly suggest that up to a point that is approximately 0.03 seconds prior to impact, Tiger's hands may be maintaining a near-constant velocity - similar to the PingMan machine.

Jeff.

 

[jmessner]

If you hold a club in front of you clubhead up toward the sky and then pivot right and left you will see that the hinge/pivot point that doesn't move right or left is where your hands meet. Using the heel pad/butt end of the club will cause an artifact as it "reverses" as the hands turn over.

-hcw

hcw - I'm having trouble visualizing your test - what is pivoting left and right?

I'm not sure the butt end actually reverses, but I agree the roll makes the butt end slow down which I guess was my point that the "slow down" depends on where you consider the hinge point to be.

 

[jmessner]

Jeff-

I was just trying to show the speed of the hinge near impact compared to the speed earlier in the downswing. It may well level off right before impact, but at a lower speed, IMHO.

The selection of the hinge point is important. I selected the heel pad or butt for several reasons, but one being that if you hold a club and cock and uncock the left wrist, the butt end seems to me to be the most appropriate hinge point.

Jay

 

[shootin4par]

Jay

Doesn't hcw bring up a pertinent point? The butt end of the club essentially "reverses" at the point of impact, and measuring it may suggest a greater degree of slowing, that doesn't reflect the "true" amount of slowing of the conjoined hand unit.

Either way, your results certainly suggest that up to a point that is approximately 0.03 seconds prior to impact, Tiger's hands may be maintaining a near-constant velocity - similar to the PingMan machine.

Jeff.

yes jeff.
ever see one of those spirals you put a coin in and it goes really slow areound the outside and slowly funnles to the center. The closer it gets to center the faster the penny spins. the closer the but of the club stays to center during release phase, the faster the clubhead

 

[hcw]

hcw - I'm having trouble visualizing your test - what is pivoting left and right?

sorry...clubhead moves from vertical to horizontal pointing to right then back to vertical to horizontal pointing left...

I'm not sure the butt end actually reverses, but I agree the roll makes the butt end slow down which I guess was my point that the "slow down" depends on where you consider the hinge point to be.

correct, that's why i put reverses in quotes...if the assembly is moving Right->Left then then the roll makes the butt end move R->L slower and the clubhead move R->L faster, the latter of course being the whole point

-hcw