Re: Up Hill or Down

["Duncan Fletcher" <dfletche@gte.net>]

----- Original Message -----
From: <Tivers@aol.com>
>
> Well, you're on to the next question already. We still don't have a
> definitive statement from the horseman-observer that a horse standing on a
> sloping plane, nose down, receives more weight on the forelegs--before any
> contortions take place.

If the horse stands with legs square underneath on a slope, then CG moves
forward and more load is carried by the fores. But horses adjust
(contortions is a loaded word - all athetes contort) to the environment. I
don't stand on a 12/12 pitch (45 degree) roof the same way I stand on the
ground. Neither do horses move on hills the same way they move on level
ground.

>Once that is established, simply, without any
> formularific obfucation, then we can proceed to the second assertion, that
> the horse is capable of countering the effects of gravity by crouching
lower
> behind, as, it is said, by moving his rear legs forward--that is moving
mass
> forward, underneath his body.

He is not moving mass - he is moving his legs forward. That does 2 things.
Assuming for the moment that the legs are straight, the top line is sloped
to the rear in reference to the slope and will be somewhat more level in
relationship to gravity thus preventing that forward movement of CG of  a
horse standing square on the slope. (Actually he will probably not keep his
legs quite as straight thus lower his back more). Because his legs (base of
support) are move forward, the load is somewhat transferred to the hind.

>
> Looking at the second aspect, hoping beyond hope that elementary physics
> remains as it has been for at least the past two weeks, let's investigate
the
> crouching phenomenon.
>
> If the horse's forefeet are sitting 24" lower than his hind feet, and if
the
> mass of the hind legs must move forward to accommodate a 24" crouch, a}
can
> it be done and, b} where does the center of mass go and, c) how does this
> affect the stride efficiency and, d) is this compensation, if it can
possibly
> exist, healthy?

a) yes
b) very minor movement forward (for all practical purposes no change - not
much weight in the leg) - but the base of support is moved forward at a much
greater rate.
c) compared to level ground, decreases. But nobody said that they could go
downhill with the same efficency as on the level.
d) is a riders weight healthy for a horse, is racing healthy, is me carrying
a 40 lb backpack healthy, is life healthy? It certainly requires much
stronger muscles (paticularly hind). I will leave it to those better trained
to get into more depth on that question.

> I'd love to see a trotting horse moving down a significant incline with a
> level back, first. I can envision a horse sliding down a hill on his hind
> legs, front in the air, in order to achieve a level back--but not a horse
at
> a trot.

I will leave this to others - my Peruvians don't generally trot. My guess is
that the back is probably not level, but lower than parallel with the slope.
And if the slope is steep the gait is probably more of a 2 beat shuffle
without much if any suspension - but I am now into speculation.

> All I need is a picture of this being done and I'll concede the entire
point.
>
> ti

Duncan Fletcher
dfletche@gte.net





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