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biomechanics of speed
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mrsruse13
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 Posted: Mon Nov 4th, 2013 01:16 am
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I have recently come across an academic article which says Black Caviar has a very long stride compared to other horses and this is the basis for her speed. Is this a representation of double suspension or independent of it?

DrDeb
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 Posted: Mon Nov 4th, 2013 01:55 am
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Might be either; we would need either sequence photos, video, a film clip, or else a single "key" still photo in order to tell whether she double-suspends like Secretariat or not. -- Dr. Deb

mrsruse
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 Posted: Mon Nov 4th, 2013 02:09 am
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Thank you! I will see if I can dig up a photo from the media; I was very intrigued after reading your article in Equus. It was a great article and I have referred it to a couple of academics I am working with; the maternal inheritance of speed in tbs is new to me--than you.

Dorothy
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 Posted: Mon Nov 4th, 2013 06:26 am
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Dr Deb,
Can you explain what you mean by 'double suspension' please?
Dorothy

DrDeb
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 Posted: Mon Nov 4th, 2013 04:48 pm
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You need to get the article, Dorothy: it's in the Nov., 2013 issue of Equus Magazine, no. 434. The article is a complete analysis of Secretariat's growth, adult conformation, and running biomechanics -- or anyway as complete as I could make it, given that I don't have infinite access to all the pictures I would have liked.

In brief, "normal" sound athletic horses use a single-suspension transverse gallop, in which the footfall for the gallop on the left lead would be right hind, left hind, right fore, left fore, suspension (hence a five-beat gait).

A horse that gets himself fouled up will "cross-canter"; this is bad for a horse due to the inability of the lumbar vertebrae to rotate about the long axis of the spine. This type of gallop is, however, normal for carnivores adapted for running, i.e. cheetahs and athletic dogs, and it is called a "rotatory" gallop. In a rotatory gallop, there are two periods of suspension and hence the animal gains an advantage because the most ground to the front is gained during frictionless flight, when no feet are on the ground. The footfall order in a rotatory gallop executed on the left lead is right hind, left hind, suspension, left fore, right fore, suspension (hence a six-beat gait).

An exceptional racehorse such as Secretariat will perform a double-suspension gallop which, however, is still transverse rather than rotatory. This protects the horse from the damage to the spine that can occur if they cross-canter. The footfall order for a double-suspension transverse gallop executed on the left lead is right hind, left hind, suspension, right fore, left fore, suspension (hence, again, a six-beat gait).

During the first suspension in a double-suspension transverse gallop, the horse assumes the "flying" posture seen in antique paintings of racehorses. The old observers were not incorrect. However, most racehorses do not actually use this mode so it would be inaccurate to picture them all running this way. -- Dr. Deb

Dorothy
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 Posted: Mon Nov 4th, 2013 05:00 pm
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Thank you, How interesting!
Dorothy

chebert16
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 Posted: Tue Nov 5th, 2013 01:25 am
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Just an observation I'd throw in there- it's common to see barrel horses cross-firing to the third barrel, which is probably one of the many reasons why they stay unsound. And having watched many many steers in the roping pen- they all cross fire- all the time at a run. Which is probably why the horse can 95% of the time catch up to them.

DrDeb
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 Posted: Tue Nov 5th, 2013 03:31 am
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Cindy, the term is not "cross fire". To crossfire means that the legs interfere or strike each other diagonally. The correct term is "cross canter" when what you mean is that the animal shifts to a rotatory gallop.

I was not aware that barrel racers frequently cross-canter, but it does not surprise me to hear it, as they are generally schooled in a manner exactly the opposite to what they actually need, i.e. the girls who own these horses almost universally have their minds on making the horse go faster, rather than what they should be developing, which is the ability to corner efficiently.

Cattle are perfectly OK using a rotatory gallop. Unlike horses, they have far more flexible spines (as any bull rider who has also tried broncs can tell you: a bull can twist his haunches around so far that he can kick the guy's hat off, which no horse can do). The bovine lumbar joint design freely permits rotation about the long axis.

As to speed, cattle vs.  horses: any cow can outrun any mounted horse anytime it wants to, for the simple reason that the horse has to run with a weight upon its back. Further, some cattle are innately speedy -- certain kinds of beef or dual-purpose cattle, and especially the ganado prieto or black fighting cattle. Hence the challenge to the real cowboy or cowgirl who knows many throws with their lariat, and who has a trained horse and who can really ride: this sets them quite apart from the dull and uninteresting competition ropers, whose repetitive workouts and unskilled riding quickly cripple their horses. -- Dr. Deb

ruth
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 Posted: Tue Nov 5th, 2013 07:53 am
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And of course the lateral agility of the Iberian bullfighting horse is legendary. No doubt most people on this Forum has seen this, but if not it's worth watching 'Merlin the Bullfighting Horse' which has been on You Tube for ages. Thank you for the reference to the article on Secretariat Dr Deb. Regards.

chebert16
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 Posted: Tue Nov 5th, 2013 12:33 pm
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Ruth, I love the Merlin video! It's mesmerizing to watch!

chebert16
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 Posted: Tue Nov 5th, 2013 12:38 pm
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That's very interesting about the cattle-it does make sense though when a bucking bull is considered- thank goodness horses spines are more rigid and can't twist like that!
And you are right about barrel racers always wanting speed above most else- when actually a cleaner turn would increase their competitive advantage alone. I'm not much of a barrel racer myself, although it is a rush to ride a barrel horse that runs like a border collie through those cans- completely happy with themselves and their job. But of course, there aren't many like that, and since I don't want to run one that isn't that way, I'm pretty slow to get one going to the rodeo-

DrDeb
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 Posted: Tue Nov 5th, 2013 02:49 pm
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OK, then, Cindy, would you tell me how your QH mare came to tear her DDF off the coffin bone? I'll need this information anyway for the other thread. -- Dr. Deb

chebert16
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 Posted: Tue Nov 5th, 2013 03:39 pm
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Yes Dr .Deb, Here is a pic of how I think it may have began. this was July 2011. Despite this shoe job, Stevie ran great for me the rest of the season, into October. It was only then, after I would give her a break, that I would notice she would come back stiff, but then seemed to walk out of it. When November came, I pulled her shoes and turned her out in our 40 acre pasture with some others. Once in awhile I noticed she seemed tender footed out there, but I thought she was just getting used to her barefootedness. In December I left to Arizona for the winter with some other horses, and left Stevie, thinking she would enjoy the 4 months off with her buddies. When I came back in the spring I noticed she was definitely off when I started slowly getting her back in shape. I took her to vets, hoof testers were negative, nothing clearly blocked out, X-Rays were normal- it was only after MRI they found the tear- this is the exact wording: I'll add that this MRI was done in July of 2012, I had not ridden her more than 3 times since the fall before.
RIGHT FORELIMB:
There is mild increased STIR signal within the navicular bone. There is a mild increase in the size of the synovial invaginations with a moderately enlarged synovial invagination present in the lateral aspect of the navicular bone. The distal border of the navicular bone is mildly irregular. There is mild effusion of the navicular bursa and a very mild amount of increased tissue within the navicular bursa. The dorsal border of the deep digital flexor tendon is very mildly irregular at the proximal recess of the navicular bursa. There is mild effusion of the digital sheath.
LEFT FORELIMB:
There is mild increased STIR signal within the medullary cavity of the navicular bone, There is a mild dorsal margin irregularity of the deep digital flexor tendon with a slight focal dorsal marginal tear of the medial lobe, at the level of the proximal recess of the navicular bursa. There is very mild proliferative tissue within the navicular bursa. When a navicular burial distention was performed, there was no evidence of adhesion formation. There is a mild, focal, increased signal within the lateral aspect of the deep flexor tendon, just prior to the insertion. Mild osseous remodeling is present on the palmar aspect of the third phalanx, at the level of the insertion of the impar ligament. The impar ligament is normal in size and signal intensity.
1. Bilateral mild increased signal within the navicular bones on STIR sequences indicates increased fluid, which may be associated with edema, contusion or hemorrhage.
2. Dilation of the synovial invaginations of the right fore navicular none can indicate mild degenerative changes.
3. Slight focal dorsal margin tear of the left fore deep digital flexor tendon.
4. Bilateral mild proliferative tissue in the navicular bursa with no evidence of adhesions.
5. Mild navicular bursal effusion of the right forelimb.
6. Mild insertional tendinitis of the left forelimb.
7. Very mild osseous remodeling of the insertion of the impar ligament on the left forelimb of likely minimal clinical significance.

So she was given 3 treatments of Tildren, each 1 week apart, and has been in "corrective" shoeing ever since. I have not ran her much, to me she still leans too heavily on the left front, and I still feel that odd stiffness, and sometimes even a noticeable, yet mild, head bob at a trot. I've been told there are lots of ways to mask her pain and run her anyway- but I won't run her unless she is sound. My last resort now is to turn her out barefoot again and let mother nature do her work- I don't know what else to do. I can't find any vet who will just tell me that she will never be sound again, it's always more treatment, more corrective shoeing, injections, antiinflammatories, etc, etc. At this point, I would love to get her sound enough to be able to teach her real collection and see what difference it can make.
Thanks again for your time! I'll also post a pic of latest "corrective" shoeing last June, which was the last time I ran her.

Attachment: Stevie front feet July 2011.jpg (Downloaded 162 times)

chebert16
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 Posted: Tue Nov 5th, 2013 03:51 pm
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I took this picture to send it to my vet for his opinion, because in my opinion, it looked really bad. He told me that it might not look pretty, but that is how she is going to have to be shod due to her condition.

Attachment: Stevie June 2013.jpg (Downloaded 161 times)


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