Two weeks ago I posted the following message to the BIOMCH-L group.

A group of colleagues and I are trying to find an estimate for the
torsional moments acting on equine tibia during normal gait for use in
mechanical testing of a new fracture fixation device. We have estimated
this moment (95 Nm) through calculations using published shear strain data
acquired on a single horse. This value seems high to me and I would like
to be able to verify it. The best option would seem to be to find some 6-
dof force plate data for equine gait. Unfortunately the only published
data that we have found is 1 or 2 dof. If anyone has such data or could
point us to an appropriate reference it would be much appreciated. Thanks
in advance. As usual I'll summarize and post replies.

I would like to thank all those that took the time to reply, especially Dr.
Henk C. Schamhardt who is attempting to provide me with the data that I need.

Thanks to all,


______Reply #1________________________________________________ ____

Please contact John Bertram at Cornell University School of Veterinary
in Ithaca N.Y. at He might be able to help you.

Mike Coleman

______Reply #2________________________________________________ __________

I suggest you contact Charlie DeCamp at Michigan State University, College
of Veterinary Medicine. I believe they have an AMTI 6 load component
force plate in one of their buildings and have collected force plate data
on horses as they run through the building. Dr. DeCamp may have the joint
torques available for you. Sincerely,

Brock Horsley
Clinical Biomechanist
Mary Free Bed Hospital and Rehabilitation Center
Grand Rapids, MI

______Reply #3________________________________________________ ____________

just a couple of considerations, I am not sure if they are relevant to you.
First of all: I have no experience with horses, but considering the 20 to
40 Nm torques acting on the human femur during gait and stairclimbing
(Crowninshield + Bergmann), I wouldn't consider 95 Nm to be too high in a
horse. (Of course your torque estimate will depend also on the Young
modulus you used...).

Conversely, I am not sure if you can measure that torque "externally", with
a force plate, as this would not allow you to include the effect of the
muscle forces.

Hope this helps. Kindest regards.

Luca Cristofolini
Laboratorio di Tecnologia dei Materiali tel. 39-(0)51-6366864
Istituti Ortopedici Rizzoli fax. 39-(0)51-6366863
Via di Barbiano 1/10
40136 Bologna, Italy

______Reply #4________________________________________________ ___________

Have you found any papers by Cal Kobluk, DVM? He was doing treadmill and
force plate studies on racehorses at the University of Minnesota in the late
1980's, and is probably still doing this kind of work. I don't know of any
specific references, but if you look him up you will probably find some
useful information.

Jennifer L. Pavlovic, Ph.D., P.E.
HCMC Orthopaedic Biomechanics Lab
Minneapolis, Minnesota

______Reply #5________________________________________________ _________

I saw your posting on biomech-l looking for 6-dof force plate data. There
was an INRA conference on animal locomotion that took place in France this
past May. I have a listing of the presentations and some of them look
like they could be helpful to you. Unfortunately, I don't know where/if
these articles have been published, but you could contact the chairman of
the conference (Eric Barrey, The
presentations which might help are:

Estimation of Horse's Movement Biomechanics Using a Dynamographic Plate
Jackowski, M.

Timing and Distribution of Strains on the Equine Metacarpus
Davies, H. M.

Joint Moments and Power in the Equine Forelimb
Colborne, G. R.

I hope this information is helpful to you. I am also interested in equine
biomechanics. Would you mind writing back and telling me a little about
the work you are doing there? Thanks.

Missy Shettlemore
Biomedical Engineering
Tulane University

______Reply #6a_______________________________________________ _____________

Here in Utrecht, The Netherlands, we spent quite some time collecting GRF-data
of horses, at the walk, trot, canter and during jumping. As a matter of
fact, we did not report on transverse forces, because these appeared to be
rather inconsistent, and relatively low. However, as you mentioned
correctly, these might be responisble for quite some torsional moment acting
on the tibia.
Digging around in some of our data, I ran into the full 3D GRF data of our
"standard horse" (the average data of 20 normal Dutch Warmbloods), at the
trot and the canter, and of jumping data of 5 horses. The following data
were found for the peak GRF in transverse direction:
trot: 0.28 N/kg
canter: 0.20 or 0.51 N/kg (leading vs. non-leading limb)
jumping: 0.12 - 0.55 N/kg

Our horses had a body mass of about 600 kg. Estimating the height of the
Tarsus above the ground to be 0.6 m, the resulting torsional moment is about
0.28 x 600 x 0.6 = 169 N.m at the trot, or almost 300 N.m during jumping. I
realize myself that this calculation is kind of simple, but it seems to be
not completely unrealistic. Your values of just below 100 N.m seem not too
high, or might even be an underestimation.

If you should like to obtain more detailed data, please let me know.

Hopefully, this information is of any help.

Henk C. Schamhardt, PhD
Department of Anatomy, Faculty of Veterinary Medicine
Utrecht University, P.O. Box 80.157, NL-3508 TD Utrecht
The Netherlands
phone: int+31-30-2534325/2534336 FAX: int+31-30-2516853

______Reply #6b_______________________________________________ _____________

you wrote:
>you sent me is very useful but there is one load missing. If there is any
>moment occuring about the vertical axis during the stance phase of the gait
>cycle, then this load will also have a torsional component about the tibia.
> Could you easily provide me with a value for this moment?

Easily: no, I have to check the computer in the lab, which is about 300 m
away from my office. Might take a little while. In the mean time, I will
also check the walking data.

>In going through the calculations that you sent me you neglected to
>multiply by the value of .6 which brings the estimated moment down to 100.8
>Nm at a trot. Since the tibia is not horizontal during the stance phase
>but rather at an angle of approximately 45 degrees, this result can be
>multiplied by the cosine of 45 degrees (to differentiate the load
>components causing torsion vs. bending) producing an estimated moment of
>71.3 Nm. This does indicate that our estimate from the strain data is not

Two times stupid from my side: you are completely right! Note, however, that
the tibia is almost vertical at the beginning of the stance phase, and
considerably more close to horizontal at the end. Furthermore, there is also
an out-of-plane component: the hocks are more close to eachother than the
stifles. A more detailed guestimation (what about this Dutch addition to the
English language!?) requires a full 3D-model. Possibly, the stamp becomes
more expensive than the letter then, as we are used to say.

One final comment, I forgot to mention yesterday: are you aware of the use
of the so-called walking cast in horses? Basically this is a steel loop,
fixed with transcutaneous pins through the bone proximal to the place where
it is damaged, running underneath the hoof. After application, the whole
thing is wrapped in plaster. In some in vitro experiments it was confirmed,
that this system unloaded the distal part of the limb for about 90%. If you
want to obtain more detailed information, please contact my colleague
Wim Back. He is vet. surgeon at the Department of General and Large Animal
Surgery. His e-mail address is:

I will come back to you with some more data a.s.a.p.

Henk C. Schamhardt, PhD
Department of Anatomy, Faculty of Veterinary Medicine
Utrecht University, P.O. Box 80.157, NL-3508 TD Utrecht
The Netherlands
phone: int+31-30-2534325/2534336 FAX: int+31-30-2516853

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