RE: [IceHorses] The Distal Limb and Weights

[Karen Thomas]

 Conclusions: The costs of swinging the limbs in the horse are
considerable and the addition of weights to the distal limb can have a
profound effect on not only the energetics of locomotion, but also the
kinematics-at least in the hind limb.     Potential Relevance: The use
of weighted shoes, intended to increase the animation of the gait, will
increase the metabolic effort of performance horses a disproportionate
amount. The additional mass also increases the joint range of motion and
potentially increases the likelihood of injury.


That's pretty clear, isn't it?  It certainly is the same conclusions that
local vets and farriers in this area seem to have reached here where gaited
horses have always been common.  As I've said before, this was the
prevailing wisdom I heard from reputable vets and farriers almost 20 years
ago when we first got Mac and our other horses.


Karen Thomas, NC



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9:26 PM

Re: [IceHorses] The Distal Limb and Weights

[Judy Ryder]

Weighting the Distal Limb Study:

Wickler, S.J., Hoyt, D.F., Clayton, H.M., Mullineaux, D.R., Cogger,
E.A., Sandoval, E., McGuire, R. and Lopez, C.

The energetic and kinematic consequences of weighting the distal limb.
Equine Veterinary Journal 2004;

Reason for performing study: It is well known that adding a load to a
horse's back increases its energetic costs of locomotion. However the
magnitude of the increase resulting from adding the load to the most
distal portion of limb has not been measured.

Objectives: Oxygen consumption will be measured in horses with mass
added to the back and added to the hooves. Because such mass
distribution will alter inertial parameters of the limbs, kinematic
measurements will be made to quantify the magnitude of change in limb
movement.

Methods: Steady-state oxygen consumption was measured in 6 horses with
a load of 2.4 kg. The load was either carried on the back or equally
distributed between the four limbs. Modified bell boots kept the mass
at the level of P3.

Horses trotted on a treadmill at speeds ranging
from 2 to 5 m/s (in 0.5 m/s increments). High-speed (250 Hz) digital
images were recorded in a sagittal plane and the positions of
retro-reflective markers located on standard positions on the limbs
were digitized for kinematic analysis.

Results: Loading of the distal limbs produced a 6.7% increase in
metabolic rate-an order of magnitude higher than when the mass was
added over the back. Although the stride period was 2% longer in
horses with loads on the distal limbs, the time of contact and duty
factor were not different. Distal limb loading increased the range of
motion in hind limbs, but not forelimbs.

Conclusions: The costs of swinging the limbs in the horse are
considerable and the addition of weights to the distal limb can have a
profound effect on not only the energetics of locomotion, but also the
kinematics-at least in the hind limb.

Potential Relevance: The use of weighted shoes, intended to increase
the animation of the gait, will increase the metabolic effort of
performance horses a disproportionate amount. The additional mass also
increases the joint range of motion and potentially increases the
likelihood of injury.


Judy
http://icehorses.net
http://clickryder.com