RE: RC: RE: Fwd: physiology of weight

[Mike Sofen <msofen@pacbell.net>]

Wonderful points, Truman.  But!  If weight were the only factor of
importance, then ONLY FW/LW riders would ever top ten.  If the physics
around carried weight are valid, then there is no way to compensate for it -
it must be in effect for every rider and horse on every ride.

My point - there must be some other aspects of the horse/rider equation that
allow MW/HW riders to win and top ten events.  I would love to find out what
those are.

Mike Sofen

-----Original Message-----
From: Truman Prevatt [mailto:tprevatt@mindspring.com]

Mike you have just answered your own question. Work required is directly
proportional to mass - that's high school physics. It takes twice the work
to
carry a 220 pound rider than it does a 110 pound ride. Since the conversion
of
chemical energy to mechanical energy (which is how the body works) is not
100%
efficient, maybe 50%, the other portion of the energy is converted to heat.
This
heat has to be dissipated. So a horse carrying a 220 pound rider has to
dissipate twice the heat as a horse carrying a 110 pound ride. Here is where
Howard may have had a good point but didn't know it :-), in the humidity it
is
harder to dissipate heat than in arid and semi-arid climates. So the heat
dissipation related to weight differences may in fact be slightly bigger
issue
in the East than the West, but I doubt it.

The more heat required to be dissipated the more sweat, the more
electrolytes
lost, the higher the stress on the metabolic system. So I would say from a
string of conclusions using no more than high school physics, there is a
significantly higher stress level on a horse carrying 220 pounds vs 110
pounds.

On question, how do you compensate for the "mitigating factor" of a horse
carrying a heavier weight producing more heat in proportion of the weight
carried?

Cheers,
Truman