I became interested in the specific conformation behind the horses’ abilities when I got myself embroiled in some of the squabbles that were fragmenting Colonial Spanish Barb Mustang etc Horse breeders in the 1970’s and early 1980’s. I found myself pointing out that refusing to register the offspring of registered horses on the basis of undefined subjective criteria undermines the credibility of a registry and that there are fundamental differences between an individual breeding horses and a horse registry. One difference is that breeding may be completely subjective while registries document objective, ideally factually based, criteria like which horse was sired by a particular stallion and out of a particular mare. This made me extremely unpopular especially when I asked for an objective definition of a mysterious quality called the ”Spanish Hip’ when I found that horses deemed to be lacking it were being refused registration.
I decided to see if there was any objective basis at all for a consistent biomechanical structure for specific types of horses hindquarters. My first problem was that the accepted mode of judging the structure of the horses hind end had people drawing a line from the point of the horses hip bone to the point of their buttock, ignoring the actual hip-joint. Although there is now some new research into horse locomotion, at that time I had to go Goubeaux and Barrier’s ‘Exterior of the Horse’, first printed in English in 1892, to find some guidelines for my search. The book was written when horses were still working animals and the authors’ focus was on the most efficient bio-mechanical structure for the desired task.
Horses are really not built to carry weight on their back. They have no collarbone, so their shoulders are a sling made of muscle and connective tissue holding up their ribcage and their spine is a long truss that is designed to allow their inner organs to hang down. The only solid bony connection of the spine is the sacroiliac joint where the spine and pelvis join. So the structure of the hind-leg, the relationship between each of the bones and the angles they make at the joints, has a profound affect on how the horse moves. The bio-mechanics of the shoulder mirror the bio-mechanics of the hip.
According to ‘The Exterior of the Horse’ the hip joints of both draught and race horse hips tend to be greater than 90o or obtuse angles when standing at rest. The hip joint is the spot where the pelvic girdle and the femur meet. It can be approximated by finding the boney protuberance of the greater trochanter on the femur. This spot is important as it is the point of leverage where large muscles that propel the horse forward attach.The relationship of the greater trochanter of the femur to the stifle and point of the hip also indicates the limit cycles and the saddle point that influence that horse’s abilities and susceptibility to injuries. You can find more on the biomechanics and schooling of different types of horses in the second book in my horse training series. Or you can join my facebook group The Square Horse.
Usually the angle between the horse’s stifle and hock, or knee-joint and ankle, is about the same as the hip, so when they are open angles, that makes the entire hind-limb rather straight. For horses whose primary work is under harness, whether that is fancy trotters pulling carriages or heavy draught horses hauling freight the most efficient hip structure is a steep pelvis from the hip-joint to the point of the hip and a near perpendicular thigh bone. That enables the horse to push forward against the harness with short strong steps and resist any backward inertia, the hind leg functioning like a ratchet.
Race horses need to be able to maximize the length of their stride by folding their hind leg up and reaching well up under themselves at speed as well as extending the hind leg completely out behind with minimal muscular effort. While the near perpendicular thigh bone is also most efficient for the racing gallop, the pelvis needs to be more horizontal so that the whole hind-leg can swing easily through a full arc like a pendulum. While the modern Thoroughbred often shows the influence of their pony mare ancestors in having a more open hip joint, the Turkomen sires that founded the breed were truly ‘rectangular’ horses with 90o hip and shoulder joints.
Sloping hindquarters became indicative of draft ancestry and rough bouncy gaits while a flat croup became highly desirable in a riding horse bred for speed. Although the Exterior of the Horse dismissed Spanish horses as ‘goose-rumped’ like a draft horse and inefficient at either hauling and racing, at least I knew where I should be looking. So I collected images of Spanish horses from nearly 500 years and over three continents, got out my protractor and my ruler and started drawing lines. Sure enough, there was a consistent and distinctive pattern found in horses of pure Maghreb Barb and Iberian descent, as well as a consistent pattern in riding horses that had had an infusion of Spanish blood.
The original Spanish horse does indeed have a pelvis as steep as any draft horse with a slope of 40o. The difference is that when the horse is at rest they have a 90o angle at both the hip and stifle joint. This ‘z’ shape makes the hind legs into springs that can collapse and extend with minimal muscular effort, so it is very easy for the horse to basically squat down and shift the burden to its hindquarters when weight is put on its back. The efficiency of the Spanish Hip is in its carrying ability, not its pushing force. Even better, when that spring is uncoiled, the horse with the Spanish Hip easily leaps like the locusts, often spontaneously demonstrating all the varieties of the airs above the ground.
Visually, the horse with a true Spanish Hip appears to have a deep round rear end with the stifle joint directly below the point of the hip. They will also appear to have a short back. This is a bit of an illusion because what is shorter is the horse’s belly line, as there is less distance between the horse’s elbow in front and its stifle in back. The square horse so desired in baroque dressage has a 90o angle at both the shoulder and the hip, but the ‘square’ is more of a diamond shape.
What I found when I started looking at the relationships between the hip-joint, pelvis ,and thigh bone was most intriguing, but my grand discovery was met with a resounding silence in the circles of Spanish Colonial Horse breeders. Suddenly the Spanish Hip became a non-issue because it is very rare even among so-called Spanish breeds. I did find it consistently in the descendants of the Monty Holbrook, Romero, and Santo Domingo horses, among the best of the North African Barbs, D’ Andrade’s Lusitanos and in the Cartujano line of Andalusians.
I have hope that the unique hip structure underlying the athleticism of the Iberian horse will bcome more widely recognized and preserved as the Portuguese Lusitano breed standard now includes the most telling and easily discerned trait of the ‘Spanish Hip’ requiring that ‘the thigh…is orientated in such a way that the patella is in the same vertical line as the hip bone’
Because the thigh and gaskin of the Spanish Hip are so much longer than in other types, mixed ancestry often results in conformation faults in the hind legs, as can be seen in many individuals among the remnants of the Spanish Colonial Horses in the USA. However, from as early as the 16th centery, Baroque horse men noted that those horses suited to highschool work were of Square and Rectangular conformation. The Baroque Rectangular horse has a pelvis of 35o, between the Galloper and the Square Horse and both the hip and stifle joints retain the 90o angle. While these Rectangular horses do have to make a muscular effort to shift weight towards their hindquarters, their hip and stifle joints can still operate as springs, opening and closing easily within the bio-mechanical limits of the joints.
The characteristics of Iberian and Maghreb Barb horses include remarkably smooth gaits and tremendous endurance under saddle, a natural flair for collection, and most notably, the leaping airs above the ground. Their true story was difficult to come by as when I looked into the history of these horses through English sources, they were sure that the finest of horses originated in Arabia where, unsurprisingly, they had colonies, while the French claimed it was North Africa where they had colonies. The Spanish, on the other hand, claimed their horses sprang directly from the Spanish soil.
I would surmise that somewhere in the mists of time there was an exceptional stallion that could leap like the locust and his sons have spread his traits through out the horse population. It is fairly certain that that stallion had to be born in North Africa because when Tariq and his Berber cavalry conquered Spain in 711 ad, their horses ran circles around the European Knights on their heavy horses.This is supported by part of the Arabian horse mythology, as they say that their founding sire was a gift from King Solomon himself, a stallion as fleet as a gazelle.
Gazelles are an interesting choice to compare a horse to as there are faster animals in the area. What gazelles are renowned for is their bouncy gait and ability to spring up into their air with one type actually being called the springbok, the springing buck. So again, I can also surmise that this stallion was prized for his ability to pass on two vital traits to his offspring:
- his willingness to work in partnership with humans
- his ability to spring into the air like a gazelle
Ongoing genetic testing is illuminating the history of the horse and their people in a most fascinating way. Genetic testing in people shows that the Tuareg Berber peoples from Libya throughout the Sahara Desert carry genetic markers that support the hypothesis that they traveled from Iberia to North Africa near the beginning of the Holocene era about 8,500 years ago. Like the maternal lines of horses, the Tuareg are characterized by village-specific maternal mtDNA lineages. Researchers speculate that the bucolic climate conditions of North Africa during the early Holocene Age when the 1700 year Dryas cold snap had brought cold and drought to Europe were a precipitating factor in the migration of people and animals to North Africa.
A last word, while I appreciate and support the gains that genetic markers have allowed breeders of Colonial Spanish Barb Mustang etc Horses in the USA to make, I would encourage them to select for the distinctive abilities and conformation of the original horse as well as the blood lines.