Conversation with Rooney.ctd

[Tivers@aol.com]

In a message dated 1/12/00 9:06:03 AM Pacific Standard Time, 
jarooney@goeaston.net writes:

<< At 09:16 AM 01/12/2000 EST, you wrote:
 >In a message dated 1/12/00 5:22:19 AM Pacific Standard Time, 
 >jarooney@goeaston.net writes:
 >
 ><< Yes and no, Tom. There is no change in the total vertical weight or the
 > percentage weight on fore and hind. There is an increase of force parallel
 > to the ground - a braking or decelerating force going downhill and an
 > accelerating force going uphill. Stress means force per unit area, and you
 > are really talking about total force and not unit force.
 > So going up and down hill does increase horizontal but not vertical force.
 > Same thing applies to the standing horse on an incline. As the angle of the
 > incline increases there must be more horizontally directed force to
 > maintain its position. Okay? Jim
 > 
 > At 08:32 PM 01/11/2000 EST, you wrote:
 > >Jim, does a horse trotting or galloping downhill experience more stress 
on 
 > >the forelegs or not? For that matter, is a horse standing on an incline,
 > head 
 > >down, carrying more weight on the front legs than on the flat or not? Why?
 > >
 > >Tom Ivers >>
 >
 >Thanks, Jim,
 >
 >Ok, my error is in the words "carrying more weight"?  Weight being vertical 
 >force. What the incline does is change the direction of force 
vectors--going 
 >downhill throws more force at the forelegs, but not more "weight". Is that 
 >correct? **** more horizontal force.
 >
 >ti
 >
 >Well, yes, the resultant vector shifts but the components - vertical force
 (or weight) and horizontal force remain the same in direction with the
 amount (scalar) of the horizontal force increasing while the vertical
 component remains constant since that is mass times acceleration of
 gravity. Remember that the resultant force is the vector sum of the
 vertical and horizontal forces. It's hard to do this without drawing
 pictures on a blackboard. Jim >>


Ok, so we're actually talking about one vector, and the effect of this vector 
in a horse trotting or galloping down hill is to put more "stress" on the 
forelegs, correct?

have you ever heard of horses that could eliminate this additional foreleg 
stress by "collection"--that is, moving the impact of their hindlegs so far 
forward as to overcome the additional stress?

The basis of this whole discussion is the claim that properly trained horses 
can make speed downhill without risking additional injury to the forelegs. 
This from a vet who has experienced 0 foreleg injuries this way. I've injured 
a few Standardbreds and TBs going down modest inclines at modest speeds. 
Sometimes it's joints, sometimes feet, sometimes interference and fractures 
therefrom. Also have had some hock and stiproblems that I attribute to the 
same situation.

Thanks for taking the time, Jim.

Tom


=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Ridecamp is a service of Endurance Net, http://www.endurance.net.    
Information, Policy, Disclaimer: http://www.endurance.net/RideCamp   
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=