Re: Newbie query: why required weight?

[K S Swigart <katswig@deltanet.com>]

On Thu, 3 Sep 1998, Truman Prevatt wrote:

> I would be pretty simple to calcualte the difference the enegy required for
> riders of different mass.  Probably as big a factor is the proportion of the
> rider's mass to the horses mass.  A 400 kg horse carrying a 150 kg rider will
> have to expend proportionally more work than a 500 kg horse carring a 100 kg
> rider.

Actually. the 400kg horse with the 150kg rider will have to (all other
things about movement of the horse being equal) do less work than the
500kg horse with a 100kg rider.

All of this, however, may have absolutely NOTHING to do with outcome of
the race.

Lest you not understand the distinction I am making understand this simple
concept:

It has never been demonstrated that the horse that does the least amount
of work will win the race. (This, BTW, is true of both sprint events and
endurance events).

So...even if I were to concede that horses carrying heavier riders ar
edoing more work (which I am unwilling to concede, and will accept a
challenge from anybody who likes to do a test to see whose horse is doing
more work).  In addition to all the variables that Joe mentioned about
terrain, footing, etc. there is also the variables of HOW the weight is
carried (i.e. dynamic placement of the load--which since f=ma, the dymanic
placement of the load is what really matters, as how the load MOVES during
the course of the movement of the horse contributes greatly to the "a"
part of that equation).

Additionally, if there is any change of elevation in the ride at all, and
the ride ends at the same place as it starts, then there is as much going
down as there is going up.  And...a heavier rider has an advantage going
down, since gravity is doing more of the work for a heavier object.

In a ride like Tevis, where there is more going down than going up, one
COULD make the arguement that being heavier actually HELPS the team get to
the finish line faster  :).  Of course, if you wanted to do the physics
math of the whole problem you would have to know WAY more than you
actually could about both the mechanics of movement in horses as well as
the coefficient of friction for each horse/rider team (so you would have
to know physical dimensions as well as kg.)

165 lbs is a stab in the dark.  It is, actually, (as was evidenced by the
debate that arose of the 165 lb requirement for eventing), a left over
from old cavalry days.  Since eventing was originally a militry trial for
cavalry, and 165 lbs was picked because realistically speaking, there
weren't any male cavalry riders that were lighter than 165 lbs.  The
eventing people, quite rightly, claimed that it was a stupid number if you
take into consideration the fact that women also participate in three day
eventing and that the number is a relic of the past.

In endurance, we don't even have the history of cavalry to draw on.
Endurance used 165lbs, because eventing did, and the sport has almost
always been dominated by women.  As a guess, I would say that atleast 25%
of endurance riders ride as featherweights (which means that they probably
weigh less than 160 lbs, with all their tack).  This being the case, a
HUGE percentage of endurance riders would be required to add useless
weight to their mounts....AND figure out where to put it, and have little
control over how that weight behaves dynamically.

All of the arguments that were used for abolishing the minimum weight
requirement in eventing are equally as applicable in endurance, and there
are even more for endurance.

kat
Orange County, Calif.