Questions at the summit

[SteveT]

@ wulsy .....

Since you summoned up Dariusz to save yer sorry arse, and he offered you some misleading info to shore up your misbeliefs, I searched through the scientific literature to come up with something definitive on knee kinetics and foot shear.

Read this and educate your ball-beating brainlet, if you can:

<A HREF="http://books.google.ca/books?hl=en&lr=&id=MnC60GN8PJ4C&oi=fnd&pg=PA20&dq=a+kinetic+analysis+of+the+knees+during+a+golf+swing,+gatt&ots=p2_tC_MLcQ&sig=rikN6kqiMGYVp1DFrJ5tAzb81Lw#v=onepage&q=a%20kinetic%20analysis%20of%20the%20knees%20during%20a%20golf%20swing%2C%20gatt&f=false">A Kinetic Analysis of the Knees During a Golf Swing</A>

And yes, I have more brains than talent when it comes to the golfswing... whereas you don't. I suspect that equalizes us out, and may even allow me to trash your butt where it counts.... because brains beats bullsh!t ... and don't play with scientific fire...!!!

 

[mandrin]

IMHO shear forces on the ground are increased by increasing the speed and range of the rotations/torques associated with those body parts closest to the ground. The closer to the ground the more this increased torque will increase the shear forces. (Obviously the reverse is valid for decreasing.)

wulsy,
You might be interested to have a peek at a previous thread - Ground reaction forces / angular momentum - where this was addressed.

 

[Dariusz J.]

The material you brought is interesting, but not very useful in the discussion, unfortunately. If you read carefully who were the subjects of the studies and what interaction was measured you'll see that neither there are natural conditions a golfer faces (imagine grass and metal spikes comparing to a rubber matt which is sort of ridiculous) nor we know what kind of golfers took part in the studies. Judging by the year of the studies they were upright plane no lower body torque players, but let's leave this argument.
Secondly, the studies concerned knee joints only where shear forces act relatively weak comparing to ankle joint because the rotational RoM of this joint is much bigger, especially when leg is bent. The main torque is being created in the foot area of course. One can feel how big are these forces while releasing the torques prematurely (see the casus of Hogan 1955 US Open who almost fell down while his rear foot slided on a muddy tee box).
Lastly, noone speaks in the thread about torques that are enough big to cause contusions (!). It is exactly the point that meeting the joint RoM always end with overcoming friction which can be easily observed on thousands of examples.
Shear forces are useful not only in sports but our everyday life. Without them one would be weak cripple asking for a help in doing most primitive movements.

Cheers

 

[wulsy]

@ wulsy .....

Since you summoned up Dariusz to save yer sorry arse, and he offered you some misleading info to shore up your misbeliefs, I searched through the scientific literature to come up with something definitive on knee kinetics and foot shear.

Read this and educate your ball-beating brainlet, if you can:

<A onclick="_gaq.push(['_trackEvent', 'Outgoing', 'books.google.ca', '/books?hl=en&lr=&id=MnC60GN8PJ4C&oi=fnd&pg=PA20&dq=a+kinetic+analysis+of+the+knees+during+a+golf+swing,+gatt&ots=p2_tC_MLcQ&sig=rikN6kqiMGYVp1DFrJ5tAzb81Lw']);" HREF="http://books.google.ca/books?hl=en&lr=&id=MnC60GN8PJ4C&oi=fnd&pg=PA20&dq=a+kinetic+analysis+of+the+knees+during+a+golf+swing,+gatt&ots=p2_tC_MLcQ&sig=rikN6kqiMGYVp1DFrJ5tAzb81Lw#v=onepage&q=a%20kinetic%20analysis%20of%20the%20knees%20during%20a%20golf%20swing%2C%20gatt&f=false">A Kinetic Analysis of the Knees During a Golf Swing</A>

And yes, I have more brains than talent when it comes to the golfswing... whereas you don't. I suspect that equalizes us out, and may even allow me to trash your butt where it counts.... because brains beats bullsh!t ... and don't play with scientific fire...!!!

Hey Stevie, don't mistakenly associate your lack of talent with intelligence and my huge talent with a lack of intelligence. Now that would be stooopid. In fact it may well be the other way about: your lack of talent arose out of a lack of intelligence. No offence intended.

BTW thanks for the article, but it's all double dutch to me bud. And its from 1998. I prefer Dariusz's 2011 answers.

 

[SteveT]

Uuum, Dariusz... they used six(6) high-speed video cameras. Also, they had to use force plates to generate comparable and consistent data, because if they went on grass the could never find uniform conditions.

You are unpublished, and until you can provide contradictory data, the 1998 study is valid. That's the scientific way.


Whoa, wulsy... if you depend on Dariusz' anecdotal comments and uncorroborated opinion, you will never believe 1.68 because you are biased to your own swing and subjective "feel" feedback... "If it doesn't feel good to me, it can't be true!" mentality. Not very scientific, if you ask me.

Okay, so the study measured shear at the knee, but what happens at the knee may also happen at the feet with GRFs. If you have another scientific study that contradicts this study, please produce it.

As for mandrin's GRF article, it's not been validated by others, and most here don't understand it anyway... and it may even contradict Dariusz' position.

It's a contest between objective science and subjective stopidity ....

 

[Dariusz J.]

They could have used even 14 cameras focused on the knee joints and still it won't be useful for the real topic for the reasons I pointed out in my previous post.

By the way, have I offended you the way you do ? I could easily include in my post some verses about your ignorance in anatomy and, consequently, lack of understanding of usefulness of such papers - but I did not despite your arrogance towards others deserved it fully. Instead, I just tried to bring arguments in a polite way. My advice for you is to widen your knowledge since your basic physics know-how combined with indigestible asslicking the Forum owner's butt impresses noone here, I think.

Cheers

 

[wulsy]

Whoa, wulsy... if you depend on Dariusz' anecdotal comments and uncorroborated opinion, you will never believe 1.68 because you are biased to your own swing and subjective "feel" feedback... "If it doesn't feel good to me, it can't be true!" mentality. Not very scientific, if you ask me.

Hey Stavros, if it doesn't feel good to me it's wrong. And I'm going to do a scientific study to prove it which I will then publish. You may then quote this study at your leisure.