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

[Brian Manzella]

Correct Michael!

And that is why the BEST PART of the MAT-T system—the club markers—shows seemingly contradictory accelerations of the club during the downswing.

For instance, in the swing of the golfer known for his tumble, it shows the club reaching a peak speed in the mid-downswing, then "re" accelerating to impact.

Instead of bashing the measurements, we deal with reality. The data on the club markers are really good, these are the numbers.........on a GLOBAL AXIS!!!!

The club itself isn't actually speeding up and slowing down and speeding up again, it is simply changing planes and showing a different speed on the global axis.

Yuppers, that's the point in that player's swing where he tumbles the club to a completely different plane, after having it accelerate on one plane for most of the downswing.

So the club—to the global reference frame—slows down, even though it isn't slowing down to the instantaneous screw axis, and since it IS gaining REAL SPEED toward impact, it "re" speeds up even to the reference frame.

 

[lia41985]

There's no planes in 3-D though...

 

[Brian Manzella]

Hips....

 

[Brian Manzella]

There's no planes in 3-D though...

There is a functional swing plane.

This golfer's club is mostly planar on a very flat plane for most of the first and some of the second phase of the downswing, but his functional swing plane is much steeper.

Hense the change in speeds.

 

[cnadon]

And then there's this nice little piece of video that's been floating around the web for some time. Kyle Reiffers hitting it 315 with a bit of hip deceleration.

Kyle Reifers breaks driver on tee shot at Crowne Plaza Inv at Colonial (2012) - YouTube

 

[hp12c]

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:

Oh snap!!!!! that is effin crazy good!!!! He spanked that ball!!

 

[Michael Finney]

Real researchers have to do this to compute instantaneous screw axis....


2.3.2 ISA computation
Segment ISA was computed at each sampled instant from
the instantaneous position and velocity of three segment
markers by applying the two-dimensional Reuleaux method
presented by Eberharter and Ravani [36] for three homologous
points of a rigid-body displacement. The dual rotating
cylinder case study presented in ‘‘Appendix 1’’ describes
ISA computation theory. ISA computation was carried out
for all possible combination of three markers affixed to the
same segment. For each case, RMS error was computed
between measured marker displacement and marker displacements
resulting from movement about ISA, where
measured marker displacement refers to the 3D coordinates
of the markers as reported by the EVaRT software prior to
conditioning and marker displacement resulting from
movement about ISA are the reconstructed marker positions
using ISA. The ISA that minimised the applied RMS error to
marker displacement was chosen as the segment ISA

2.3.4 Computed variables
When studying gross rotations as a kinematic chain of
ISAs, it is assumed that the magnitude of the perpendicular
component of marker velocity v\ will account for the
majority of the total velocity; thus the parallel component
of marker velocity v==\v? and therefore the majority of
marker displacement is through a rotation about the ISA.
Furthermore, it is assumed that motion about the ISA is
representative of joint motions, which have dominant axes
of rotation, providing a useful expression of that segment’s
displacement. To verify that joint motion is well represented
by ISA, a marker velocity ratio and ISA position and
orientation were computed at the instant where each ISA
achieved its respective maximum angular velocity, as the
instant where the magnitude of segment angular velocity is
maximised can reveal the segment dominant axis of rotation.
ISA position and orientation are computed differently
for each ISA for comparison with the expected segment
axis of rotation.

2.3.6 Method verification
An independent assessment of the ISA theory was carried
out using the Euler–Cardan method [41]; development of
the method will not be repeated here. Briefly, segment
Euler angles were computed using the Z–Y–X Euler convention
[42] relative to the x, y and z-axes of each segment’s
local coordinate frame. The local coordinate frames
of the pelvis and shoulders were consistent with those used
to determine the location of ISAP and ISAS, respectively,
as discussed above. The humerus local coordinate frame,
computed based on the recommendations of Wu et al. [22],
was chosen to quantify left arm motion.
Maximum segment angular velocity, with corresponding
percent downswing, as well as velocity ratios were calculated
using the Euler angles method for comparison purposes.
Velocity ratios were computed as the ratio of
segment translational velocity, computed from the origin of
the segment local coordinate frame, to marker velocity
resulting from segment angular velocity, computed from
the segment Euler angles. This quantifies the relative
magnitude of segment translation to segment rotation and
provides a point of comparison for the ISA velocity ratio.
Results of the golf swing analysis, as determined with this
method, are provided in ‘‘Appendix 2’’. For comparison,
maximum segment angular velocity, with corresponding
percent downswing, computed from motion about segment
ISA are provided in ‘‘Appendix 3’’.


Please, please, please - let the researchers work in peace

 

[Brian Manzella]

This thread EVOLED into a debate on whether or not the hips do—AFTER REACHING PEAK SPEED—significantly lose speed pre-impact.

The answer is yes. They do in the best golf swings.

We have no doubt that we are on the right side of this.


Does ANYONE here disagree?

 

[Brian Manzella]

Still looking for one single marker-based system graph/readout with a speeding up pelvis through impact of a decent player.

The count right now is a couple of hundred I have seen the other way, and zero speeding up.

 

[dwurzer]

Art's suggestion:

How about getting together in the same research lab and analyze the same golfer and coming to some scientific conclusions? This infighting just slows the process of finding the truths about the golf swing.

I think we all want to advance the knowledge base of golf instruction. How about getting together?

 

[Brian Manzella]

How about getting together in the same research lab and analyze the same golfer and coming to some scientific conclusions? This infighting just slows the process of finding the truths about the golf swing.

I think we all want to advance the knowledge base of golf instruction. How about getting together?

I would show up any time, any where, as long as there were some real scientists around and a referee.

Put it together Doc, and I'll buy my flight.

 

[Brian Manzella]

Just in case anyone missed this...


We are going to find the best biomechanics lab available in Southern Cal. That's where a lot of them are.

We are inviting whoever wants to attend, or test their idea on this subject.


It will be videotaped and posted up.


This should put an end to it for any reasonable human.

 

[Brian Manzella]

Dr. Wurzer has a lot of contacts. All the equipment companies are not far from each other and some have outstanding labs and no horse in the race. Some of the best research universities are there as well.

We will find a place with the best machines available, and an impartial biomechainst, plus at least one other scientist.

Dr. Wurzer can moderate.

We will do tests on whether or not a high-end, high speed swing can be performed without the pelvis slowing down through impact. I am sure we will test some other things as well. Might as well.

I will bring a high end 115+ student with me. Billy McKinney should be able to find another easily among his students.

The invitation is open to ANYONE who wants to test their hypotheses.

We will video the proceedings and post it up.

I am going even if no one else attends, doing the tests, and posting the video.

 

[lia41985]

We will do tests on whether or not a high-end, high speed swing can be performed without the pelvis slowing down through impact.

Brian,
Why do you keep wanting to measure the unitary pelvis when I told you, over private message, that I want to see markers on each of the hips? Remember my example about how when there's separate markers on each wrist we're able to see that the hands don't have a unified movement, velocity, and or acceleration? Don't dip on dimming some light on the complexity.

 

[Michael Finney]

 

[Michael Finney]

Some reading material....

1. Burden AM, Grimshaw PN, Wallace ES (1998) Hip and shoulder
rotations during the golf swing of sub-10 handicap players.
J Sports Sci 16:165–176
2. Cheetham PJ, Rose GA, Hinrichs RN, Neal RJ, Mottram RE,
Hurrion PD, Vint PF (2008) Comparison of kinematic sequence
parameters between amateur and professional golfers. In: Crews
D, Lutz R (eds) Science and golf V: proceedings of the World
scientific congress of golf, Phoenix, United-States
3. Bunn JW (1972) Scientific principles of coaching. Prentice-Hall,
New Jersey
4. Cochran A, Stobbs J (1968) The search for the perfect swing. JB
Lippincott, New York
5. McTeigue M, Lamb SR, Mottram R, Pirozzolo F (1994) Spine
and hip motion analysis during the golf swing. In: AJ Cochran,
MR Farrally (Eds.) Science and golf II: proceedings of the World
scientific congress of golf, St Andrews, Scotland
6. Robinson RL (1994) A study of the correlation between swing
characteristics and club head velocity. In: AJ Cochran, MR
Farrally (Eds.) Science and golf II: proceedings of the World
scientific congress of golf, St Andrews, Scotland
7. McLaughlin PA, Best RJ (1994) Three-dimensional kinematic
analysis of the golf swing. In: AJ Cochran, MR Farrally (Eds.)
Science and golf II: proceedings of the World scientific congress
of golf, St Andrews, Scotland
8. Myers J, Lephart S, Tsai Y-S, Sell T, Smoliga J, Jolly J (2008)
The role of upper torso and pelvis rotation in driving performance
during the golf swing. J Sports Sci 26:181–188
9. Teu KK, Kim W, Fuss FK, Tan J (2006) The analysis of golf
swing as a kinematic chain using dual Euler angle algorithm.
J Biomech 39:1227–1238
10. Vena AS, Budney D, Forest T, Carey JP (2011) Three-dimensional
kinematic analysis of the golf swing using instantaneous screw
axis theory, Part 1: methodology and verification. Sports Eng
(in press)
11. Vena A, Carey J, Liggins A, Kawchuck G (2008) Effect of
sampling rate on accuracy and relative error of motion capture:
system evaluation for golf biomechanics research. In: Fahim A
(ed) Canadian society of mechanical engineering forum 2008.
Ottawa, Canada
12. Leardini A, Chiari L, Della Croce U, Cappozzo A (2005) Human
movement analysis using stereophotogrammetry. Part 3. Soft
tissue artifact assessment and compensation. Gait Posture
21:212–225
13. Moore KL, Dalley F (2006) Clinically oriented anatomy, 5th edn.
Lippincott Williams & Wilkins, Baltimore
14. Winter DA (2004) Kinematics. In: Biomechanics and motor
control of human movement, 3rd edn. Wiley, NJ, pp 13–58
15. Chiari L, Della Croce U, Leardini A, Cappozzo A (2005) Human
movement analysis using stereophotogrammetry.
16. Che`ze L, Fregly BJ, Dimnet J (1998) Determination of joint
functional axes from noisy marker data using the finite helical
axis. Hum Mov Sci 17:1–15
17. Eberharter JK, Ravani B (2006) Kinematic registration in 3D
using the 2D Reuleaux method. J Mech Des 128:349–355
18. Putnam CA (1993) Sequential motions of body segments in
striking and throwing skills: descriptions and explanations.
J Biomech 26:125–135
19. Kenny IC, McCloy AJ, Wallace ES, Otto SR (2008) Segmental
sequencing of kinetic energy in a computer-simulated golf swing.
Sports Eng 11:37–45
20. Van Gheluwe B, Hebbelinck M (1985) The kinematics of the
service movement in tennis: a three-dimensional cinematographical
approach. In: Winter DA, Norman RW, Wells RP,
Hayes KC, Patla AE (eds) Biomechanics IX-B. Human Kinetics,
Champaign

 

[dschultz6072]

This isn't from 2000. Not model.

 

[hp12c]

Dr. Wurzer has a lot of contacts. All the equipment companies are not far from each other and some have outstanding labs and no horse in the race. Some of the best research universities are there as well.

We will find a place with the best machines available, and an impartial biomechainst, plus at least one other scientist.

Dr. Wurzer can moderate.





We will do tests on whether or not a high-end, high speed swing can be performed without the pelvis slowing down through impact. I am sure we will test some other things as well. Might as well.

I will bring a high end 115+ student with me. Billy McKinney should be able to find another easily among his students.

The invitation is open to ANYONE who wants to test their hypotheses.

We will video the proceedings and post it up.

I am going even if no one else attends, doing the tests, and posting the video.

Oh yeah! please say its near anaheim!

 

[wulsy]

Does a crap swing include negative acceleration of the hips/pelvis before impact? According to TPI it does.

 

[Lindsey Newman]

An imagined conversation with Ben Hogan after a sip of a gin martini and taking a drag from a Chesterfield:



Me- "Ben, what were you trying to do with your hips over that final shot at Merion?"

Ben- ".....(silence)....."