Gait To Gate

The scene at a horse sale is familiar. The smell of coffee fills the air as early morning enthusiasts walk through the barns. A "first-time-off-the-farm" filly whinnies as her dam is trotted down the aisle for a group watching her stride. A man watches a strong chestnut mare extend at a trot around an arena. A woman crouches down before a colt as he walks toward her, carefully evaluating the youngster's front legs.

Good gait quality seems to be a prerequisite for good performance. For decades, we have been striving to improve our horses' elegance of gait and performance under saddle through breeding and selection. But judging a horse's movement is considered an art. Many factors make it a very difficult skill to master--shoulder movement, impulsion, strength, extension--the list goes on and on. But what about judging a foal? Can we accurately access a horse's mature movement by evaluating its' gaits at a young age? What changes take place during a horse's growth spurt?

Willem Back, DVM, PhD, from The Netherlands, answered these questions from his studies at Utrecht University. He presented this material at the 1995 annual convention of the American Association of Equine Practitioners. Back has determined that judging locomotion at an early age can accurately predict future performance.

"An important criterion for selection of sport horses, apart from elegance and efficiency of gait, should be a low risk for developing lameness," said Back.

He discussed a study conducted at Utrecht University that included 24 Dutch Warmblood foals, all raised under standardized feeding and housing. At three months of age, the foals were trained to walk, trot, and canter on a treadmill. Markers were glued to the skin and used as landmarks for a computer to map the movement of the foal's limbs.

"The movement of the leg at different points is called kinematics," Back explained. The markers at the different segments of the limb detect three light beams emitted by a scanner and the computer calculates the kinematics of the gait, which are based on the three following standards:

  • stride duration--the time it takes for a horse to make one complete stride;
  • stance duration--the length of time the hoof is on the ground during a stride;
  • swing duration--the length of time one hoof is off the ground.

Records were taken and continued as the foals got older--from four to 26 months old. Since the trot is the most important gait for selection of horses, the group of foals was evaluated at various speeds at a trot. Naturally, the foals grew in weight and height as the study progressed, so the variables were adjusted accordingly to create an accurate model of comparison.

"This study proves that the stride variables are similar in foals and adults," Back stated.

Each individual horse has its own distinct gait pattern. This pattern remains the same even after growth and further bone development has taken place, according to findings of this research. Apparently, kinematic variables are already mature at a young age, so the gait appearance of a foal is an adequate representation of how he or she will move as an adult.

"We call it kinematic fingerprinting," Back explained. "Just like a human fingerprint, a foal's locomotion is unique and virtually remains unchanged with time."

Taking The Trot One Step Further

Now that you have a foal moving in front of you, what do you look for? Another study at Utrecht University in 1994 identified specific criteria to use when selecting for gait quality. The trot of the same group of 24 Dutch Warmbloods was evaluated at the age of 26 months by a judge and by a computer.

The horses were scored at a trot based on three criteria--length, strength, and suppleness. By evaluating kinematic variables at various points throughout the body, researchers were able to determine what mode of actions contribute to gait quality and elegant movement.

They found that variables of the shoulder, elbow, and carpal (knee) joints did not significantly contribute to a high-scoring trot. In addition, the pelvis, hip, and hindlimb fetlock were not found to correlate significantly with good movement.

"Horses with a better gait appeared to have larger fetlock extension only in the forelimb," Back commented. "The spring-like action of the fetlock joint in the forelimb is essential for horses to reduce the shock of limb-ground contact and smoothness of gait. This makes the action of the fetlock the most crucial variable in the forelimb."

Horses with high-quality trots also appear to have more flexion in the stifle and tarsal (hock) joints.

Another contributing factor to a quality trot is scapular rotation. Apparently, increased scapular movement is essential to increased stride length. More retraction in the forelimb and more protraction in the hindlimb increase the length of stride. Horses with a better trot, therefore, move forward because they are "closed" between forelimbs and hindlimbs during suspension.

So take note at foal sales: The trot of the foal next to its dam is the same trot that it will perform in future arenas. Look at the fetlock, hock, stifle, and scapular movement. Enlarge the picture, and you know what your investment will look like in a few years.

About the Author

Willem Back, DVM, PhD

Willem Back, DVM, PhD, is currently staff surgeon at the Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht, The Netherlands. He has recieved numerous awards and honors, and in 2008 he was invited as visiting Professor in Equine Orthopaedics for Ghent University. As staff surgeon he has special interest in fracture repair and hoof orthopaedics, and his research topics are mainly focussed on lower limb biomechanics of sporthorses and clinical genetics of orthopaedic diseases, in which he supervises and supports PhD students. Dr. Back is a past president of the Netherlands Equine Veterinary Association (NEVA) and founding president of the Federation of European Equine Veterinary Associations (FEEVA). He and his wife have three children, and he enjoys jazz, classic car restoration, and many sports in his free time.

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