RC: Re:overweight an issue?

["Jana Crewett" <jfcr@ceh.ac.uk>]

.another German stepping in here (we're obviously an argumentative
lot ;-))

Wolfgang,

did the South African study mention any other measured values rather
than only the riders' weight? In order to compare it to Susan's study
(which found that the really important factors the determine whether a
given horse will finish a ride were body condition score and total
horse+rider weight), it would of course be interesting to know how the
SA study compares to Susan's data, now that we know the two studies
seemingly contradict each other regarding the effects of rider
weight.

I don't have any data or results to contribute, but I've been
following the discussion and to me those two studies are not as
incompatible as it first looks:

1. Tevis is a hilly, relatively slow ride - South African rides are
mainly known to be fairly fast (at least the winning speeds look quite
fast to me compared to UK speeds).
Susan, with data from the fairly slow Tevis ride, concluded that if
the horse has "enough fuel in the tank", it can carry a heavier rider
with no drop in performance, it will simply have "less reserve" after
the finish. At higher speeds, the "energy equations" might look quite
different - the heavier rider will put *much* more extra strain on the
horse, so that, despite its good condition score, the horse now has no
longer "enough fuel" for the added task of carrying more weight around
the course at winning speeds.

2. The SA study did not give the horses' weights.
Heavier riders tend to ride larger horses. Susan had already found a
significant rise in lameness incidences once the total horse+rider
weight got larger than x pounds - maybe the South African study was
seeing a similar effect but the researchers did not notice it as they
were not looking at total horse+rider weights? 

3. The SA study did not look at condition scoring.
Condition score prior to the ride was found to be *the* most
important factor determining completion rates by Susan, so I for one
would find it very interesting to see whether this factor shows up at
all  in any other studies on the subject. My one doubt with the
condition scoring is that it might be a rather subjective measure,
especially when going into the finer details and deciding between a
"4.5" and a"4". So, it would be interesting if Susan's results are
"repeatable" with someone else doing the condition scoring or whether
there might have been a bias in Susan's study which linked certain
characteristics of successful horses to certain values in the
condition score.

4. The SA study seems to come to a conclusion of the form "x extra kg
lead to a y km/h slower speed".
That I find a very strange conclusion to draw as, even with their
large sample size, speeds are controlled by so many factors that it
seems very "brave" to relate them to one variable alone, even if they
show a reasonable degree of correlation. This type of conclusion does
make sense for a treadmill test, where all other variables (incl. the
horse) can be kept constant, but at an endurance ride many other
factors determine speed. One obvious one would be that heavier riders
might, on average, be older and less competitive, riding for
completion rather than racing for top ten and thus obviously achieving
lower speeds. These other factors might have been different in the
Tevis riders and horses, hence Susan did not pick up a drop in speeds
apparently caused by rider weight.


So - I'll be back to lurking now and hope for more interesting
discussion on this topic!

Jana