September 19, 2016 
The most important aspect of show jumping performance is the ability of the horse to keep all of the rails in the cups.
Horses that have a relatively low percentage of rails knocked down are termed “careful,” while those that always seem to have a few rails may be termed “lumberjacks.” One of the central questions of our sport is whether the carefulness of a horse can be predicted early in life: Are there tests that can be done to measure how a horse may perform in the ring later in its life?
The first step to answering this question is to accept that all horses will have rails; there is no horse in existence that will never knock down a rail.
For example, in 2015, Quickly de Kreisker was the top horse (meaning he acquired the most FEI ranking points). However, if you look at the figure below, it is readily apparent that this horse did not only jump clear rounds. Instead, only 29% of the rounds at the 1.55-meter or 1.60-meter height in 2015 were clear rounds.
That same year, Hello Sanctos won the Rolex Grand Slam of Show Jumping (a truly amazing feat). But again, if we look at the horse’s competition performances in 2015, we see the gelding was not only jumping clear rounds (69% clear at the 1.55-meter or 1.60-meter height).
The purpose of this article is not to go into too much detail about why a horse may or may not be careful (I will save that for another day). Instead, I will take a brief look at some interesting experiments that have been done attempting to correlate tests done outside of the ring to show jumping competition results.
Horse Temperament Tests
Certain temperament traits (e.g. fear, boldness) have been associated with show jumping performance.
A recently published experiment (Lansade et al. 2016) examined a few tests of fearfulness, and attempted to correlate a horse’s temperament to performance in the ring. They measured fearfulness in young horses by examining how the horse reacted to novel objects, novel surfaces, and so on. The researchers then observed the horse’s behavior under saddle and during competition.
Results indicated that more “fearful” horses were more difficult to ride (e.g. shying, head throwing, less responsive to rider commands), but were actually less likely to knock down rails as compared to less fearful horses.
Tactile Sensitivity Tests
The same research group (Lansade et al. 2016) also examined the horse’s response to touch in an attempt to correlate tactile sensitivity to jumping performance.
To do this, the researchers took small probes that apply a very light touch to skin, and applied these probes to the horse’s withers area. Horses that contracted the platysma muscle (i.e. quivered) under a lighter touch were deemed to have greater tactile sensitivity.
And as we may expect, the horses that are more sensitive to touch are more careful in the ring, having fewer rails. It is possible that the increased tactile sensitivity of these horses caused them to be more adverse to touching rails.
Scott Brash and Hello Sanctos. (flickr.com/Franz Venhaus)
Repetitive Stepping Test
A friend of mine, Dr. Michel Heijnen, did a fantastic study in humans a few years ago, which asked adults to step over a small obstacle (~250 consecutive times), and he would count the number of times individuals hit the obstacle.
Similarly to horses, he observed some individuals hit the obstacle less (more careful) and others hit the obstacle more often (lumberjacks). So I replicated his study, but with a number of different horses, ranging from amateur-friendly jumpers to 5* Grand Prix horses. Again as expected, the horses that are competing at the top of the sport had greater bodily awareness when walking over the obstacle, and hit it less frequently with their legs as compared to less careful horses.
Muscle Fiber Composition
Another often overlooked aspect of a top quality horse is the composition of its muscle. For a horse to jump, forces must be generated by muscles in the correct magnitude and timing to perform a powerful jumping movement and raise the body up and over the fence.
In very general terms, horses, like humans, have different muscle fiber types. Some fiber types produce low force (slow-twitch fibers), and others produce high force (fast-twitch fibers). Given the requirements of show jumping—generating a large amount of power as the horse takes off for each jump as well as galloping around the course—it is important to have an abundance of the muscle fiber type that can produce a large amount of force.
A research group in France (Barrey et al. 1999) correlated the percentage of fast-twitch muscle fibers in two muscles that are important for generating force on takeoff, the gluteus medius and biceps femoris,to performance in competition. They found that horses with a greater proportion of fast-twitch muscle fibers performed better.
Summary
- Certain behavioral traits correlate with performance of show jumping horses
- Increased tactile sensitivity is correlated with improved show jumping performance
- Bodily awareness as determined by repetitive stepping correlates with performance level in jumping horses
- Percentage of muscle fiber type is related to the performance level of show jumping horses
References
Barrey et al. (1999) Heritability of percentage of fast myosin heavy chains in skeletal muscle and relationship with performance. Equine Exercise Physiology, Equine Veterinary Journal Supplementary 30: 289-292.
Heijnen et al. (2012) Factors leading to obstacle contact during adaptive locomotion. Experimental Brain Research 223: 219-231.
Lansade et al. (2016) Development of personality tests to use in the field, stable over time and across situations, and linked to horses’ show jumping performance. Applied Animal Behaviour Science 176: 43-51.
About the Author
Dr. Tim Worden has worked as a sport scientist with numerous FEI-level show jumping riders. He has a PhD in biomechanics and specializes in applying human high-performance training techniques to horses.
