If you want your jumping horse to be a successful and “happy athlete,” choose – and train – that horse wisely.

But what is the wisest way to choose and train a show jumping horse?

According to equine biomechanics specialists, traditional equestrian wisdom can certainly point riders on the right path. Meanwhile, science is making great leaps and bounds in using objective measures to verify whether the traits that equestrians perceive to be important, are actually able to identify horses with superior jumping performance, with the animal’s health, welfare, performance, and sustainability in mind.

A new hi-tech study combining surface electromyography, to measure muscle activity, and biomechanical analyses has just revealed that better performing jumping horses show strong hindlimb impulsion and muscle power—exactly as many equestrians already suspected.

However, aesthetic forelimb traits, for example the ability to “tuck up”/flex the forelimbs, did not differ significantly between better or worse performing jumpers, contrary to what riders may have suspected, said Lindsay St. George, PhD, of the School of Sport and Health Sciences at the University of Central Lancashire in Preston, U.K.

The results from this study could help people fine-tune their selection and training processes for jumpers, not only to improve performance but also—and perhaps more importantly—to develop training plans that ensure horses are fit for their job..

“Our study conveys a strong message about the importance of developing appropriate muscular strength for force production during jumping,” she said.

“Based on the significant differences that we observed in hindlimb muscle function in the better performing horses, specifically in the middle gluteal muscle, we emphasise the importance of prioritizing and including strength training in a jumping horse’s training/conditioning programme, with a particular focus on strengthening the hindlimb muscles.”

Such prioritization would have clear implications for both performance and the horse’s physical well-being, according to St. George.

“Although we relate our findings to athletic performance, they can also be extrapolated to the development of appropriate conditioning programmes for jumping horses, which could reduce the risk of injury and improve career longevity and welfare for these horses,” she said.

St. George and her fellow researchers first set out to know which criteria equestrians with varying experience used to identify a good show jumping horse, as well as what training methods they commonly employed for these horses.

So, using an online questionnaire, they asked equestrian coaches and riders of all levels with show jumping experience about their selection preferences —what they’re looking at when they’re assessing new sport horse prospects. The questionnaire was shared widely and the research team obtained an international sample.

From the 225 completed questionnaires, they found obvious preferences for specific movement traits when evaluating potential show jumpers, which included hindlimb impulsion, position at take-off, and aesthetic forelimb traits.

Next, the research team – including St. George’s colleagues from UCLan, Dr Sarah Jane Hobbs, PhD, Prof. Jim Richards, PhD and Dr. Jonnie Sinclair, PhD, Hilary Clayton, PhD, of Sport Horse Science in Mason, Michigan (USA), and Dr Serge Roy, Sc.D., of Altec/Delsys Inc. — ran tests to see how accurate those criteria were.

They equipped 17 horses with 3D motion capture reflective markers and wireless Delsys Trigno surface electromyography (sEMG) sensors.

Image of the placement of anatomical markers and sensors placement for the analysis of jumping biomechanics

Image showing the anatomical locations of markers (white and turquoise spheres), segments (black lines) axes (red, green and blue lines) and sEMG sensors (red arrows). More detail can be found by reading the full paper at https://doi.org/10.3390/ani11020414

Horses were then ridden by their normal rider and sEMG and 3D motion capture data were collected from horses executing a  one-meter-high jump at a canter.

The study included three groups of horses: elite jumpers (competed up to 1.60 meters), lower-level jumpers (competed up to 1.0-meter fences at the time of the study), and lesson horses from riding schools sometimes competing in unaffiliated shows (also up to 1.0-meter fences).

The researchers found that the better performing jumpers, as defined by their ability to raise the CM during jump suspension, approached the jump faster, lifted their hindlimbs off the ground earlier, and gathered the hindlimbs up more quickly after take-off.

Their muscles—in particular the middle gluteal muscle—had shorter contractions during take-off. This apparently led them to generate muscle power and vertical impulse more rapidly as they prepared for take-off.

In other words, many of the opinions of equestrians, gathered from the questionnaire study, were verified by objective measures of movement and muscle function, as data showed that  engagement, impulsion and hindlimb muscle power really do represent  important performance criteria in a jumping horse, St. George said.

However, the role of the forelimb during the approach stride, as well as the forelimb and hindlimb joint movements while the horse is in the air, seem to be less important for distinguishing better performers over sub-maximal fences—contrary to what the riders had suggested in their questionnaires, she added.

Image of the placement of anatomical markers and sensors placement for the analysis of jumping biomechanics

Illustration of joint angles, segment angles, segment lengths and the center of mass (CM) target used in the kinematics analysis. More detail can be found by reading the full paper at https://doi.org/10.3390/ani11020414

“We observed very few significant differences in measured peak joint flexion/extension angles and no significant differences for overall limb shortening/compression across the groups, in both the forelimb and hindlimb,” St. George said.

“I found this particularly interesting as we know from the previous questionnaire study, and anecdotally, that equestrians do tend to place emphasis on traits that require greater joint flexion/extension, for example: the horse’s ability to “tuck” or “elevate” the forelimb at take-off and during jump suspension.

“Of course these traits are aesthetically pleasing and functionally important for minimising jumping faults,” she continued. “However, we found that the time taken to reach certain peak joint angles and maximum hindlimb shortening differed significantly between groups, suggesting that the horses with the capacity to jump higher were able to flex/extend their joints more rapidly at take-off or during jump suspension (depending on the variable). So although the joint angles themselves didn’t differ between groups, the amount of time that it took to reach these peak angles was different. In combination with other sEMG and kinematic variables, this finding illustrated the enhanced neuromuscular control of the better performing horses.”

“It is, however, important to note that we studied a submaximal fence that was 1 metre high and we only looked at peak joint angles, which are a snapshot in time. In future studies, analysing these joint angles continuously across the entire jumping effort and also measuring them over larger fences could reveal differences between the groups that weren’t observed in our study.”

The results highlight the need for good muscular training to improve jumping horses’ health and welfare, according to St. George. “Our study has shown that the capacity for producing hindlimb muscle power during jump take-off is important for performance, but studies have also shown that muscular weakness and/or fatigue in human and equine athletes can increase the risk of musculoskeletal injury and that appropriate muscular strength in human athletes can reduce the risk of soft tissue overuse injuries,” she said.

“Muscles initiate movement but also support the joints during loading by damping the high mechanical forces that are present such as during jumping and landing,” St. George added. “When this function is hampered by muscular weakness, injury, or fatigue, undamped loading forces can unduly stress the joint and its support structures or be redistributed and lead to overloading of other muscles or associated soft tissue structures, like tendons and ligaments. This is part of a known injury mechanism, which we see commonly in the distal (below the carpus/hock) limbs of jumping horses.”

While the sEMG and 3D motion capture technologies that the team used provided strong, objective data on each horse, their use in everyday practice by riders or breeders for selection or training purposes is probably not feasible…at least not yet, according to St. George. However, developing tools for use in practice was not the purpose of the study, which was instead to confirm—or not—the criteria that riders believed to be helpful in identifying a good jumping horse. This information can then be applied practically without riders actually having to replicate the methods employed in the research.

“Realistically speaking, the equipment costs, set-up, specialty training, and time requirements for collecting, analysing and interpreting these data means that replicating our study in real world situations may not be practical—at least not for obtaining instant results,” she explained.

“That being said, there are an increasing number of commercial products available, which use inertial measurement (IMU) technologies to evaluate equine movement from both clinical and performance perspectives. These IMU sensors are portable and have associated software that can analyse results quickly for the user to interpret. Advances in technology are critical to enabling us to acquire high quality EMG data under challenging conditions which would have deteriorated the signal if we were using older technologies. We rely on wearable sensors from Delsys Inc., which has made a number of inroads to more usable recording equipment for human and animal athletes. Further research in this area may lead to more specific biomarkers that could be captured with only a few EMG and inertial (IMU)  sensors.  This could be of practical use by members of the equestrian industry because it is otherwise difficult to visualize changes in muscle dynamics without such recording devices.

The study by St. George, L.; Clayton, H.M.; Sinclair, J.; Richards, J.; Roy, S.H.; Hobbs, S.J. titled ‘Muscle Function and Kinematics during Submaximal Equine Jumping: What Can Objective Outcomes Tell Us about Athletic Performance Indicators?’ is published in Animals 2021, 11, 414. It is open access and can be read in full here.