What's difficult to do in the models is to accurately model all of the
possible variations in muscle contraction that are possible. Most of the
force/torque models in the physics models are relatively simple (constant,
triangular, square, sloped, etc.). Whereas we humans can apply a very
complex force/torque history to the club. In a sense this defines
'feel'. What I think is unresolved is how much difference it makes to use
a simple model instead of a complex one. It may feel different to two
golfers, but still produce basically the same club motion. If the club
motion is different is this due to the differences resulting from feel or
is it simply that 'feel' is so nebulous that it is impossible to
define? It is very possible (likely, in fact) that a club swung by two
golfers instrumented to prove that the club has been swung exactly the same
by both golfers will feel entirely different to those two golfers. Ah, the
joys of human testing.
Alan Brooks
At 11:10 AM 8/15/2006 -0700, you wrote:
--- Dave Tutelman <[EMAIL PROTECTED]> wrote:
> What is your belief based on? I'm not baiting you,
> I'd simply like to know.
> :-)
Fair enough. It's just a gut feeling. I guess it's
based on the fact that even among good golfers, a
specification or feature that helps or is liked by one
golfer, hurts or is disliked by another. The human
element seems to play such a huge role that attempts
to reduce it to science seem to me to come up short.
In other words, it seems there is as much art as
science involved.
Like backweighting. You say, I assume correctly, that
current physics models don't show much affect from
backweighting. Yet some golfers love it.
Thanks for your concise explanation of the models.
That helps.
-Don M
>
> Seriously...
> The golf swing MUST be capable of modeling with
> physics. I don't know
> anybody personally who has ever said that golf clubs
> follow a
> different set of laws from everything else in the
> universe. The only
> issue is how complex the physical model needs to get
> before it
> reflects the important things in a golf swing.
>
> Around 1990, Ted Jorgensen did an extensive study
> that resulted in
> his book, "The Physics of Golf". He was Professor
> Emeritus of Physics
> at the U of Nebraska. (He died this year.) While the
> book covers a
> number of very interesting topics, his major
> contribution was
> creating a physical model of the swing that agreed
> with measurement
> taken from a real golfer.
>
> A good golfer was intrumented with reflective dots
> at the joints and
> at important stations on the golf club, and his
> swing recorded with
> strobe flash. Then Jorgensen started with the
> simplest physical model
> (the double-pendulum described by Cochran & Stobbs
> -- probably known
> well before that), and tried to match the model's
> behavior with that
> of the measured golf swing. He had to add complexity
> to the model
> quite a few times before he had a good match. But he
> DID get a match that:
> * Mirrored pretty much all the recorded golf
> club behaviors
> during the downswing.
> * Accounted for observed changes in performance
> resulting from
> changes in the parameters of the model (e.g.-
> addition of wrist
> torque in various points of the swing, head movement
> during the swing, etc).
>
> So I'm fairly confident that Jorgensen's model is
> quite capable of
> reflecting the sort of gross behavior that
> backweighting would
> affect. And Max's program is a mechanization of
> Jorgensen's model.
>
> Cheers!
> DaveT
>
>
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