Orthopedics

Correlation Between Gait Asymmetry and Performance?

By Joy Curzio

There might not be a correlation between gait asymmetry and performance, according to a recent study presented at the 2023 AAEP Convention

Erin Contino, MS, DVM, DACVSMR, and her team sought to determine actual prevalence of gait asymmetry and whether there was a correlation with performance. The gait asymmetry score supports the common notion of a “serviceably sound horse,” she said. Based on a trend seen in dressage horses, however, as well as on previous evidence, it could be that those disciplines, which are graded subjectively, are more influenced by gait asymmetry than those that are graded objectively.

“I think what this really highlights is that there may be a better way to highlight a horse’s readiness to compete,” said Dr. Contino, who is an associate professor of equine sports medicine and rehabilitation at Colorado State University.

Please note that although the term “lameness” was used in the actual presentation, Dr. Contino noted for Modern Equine Vet that the study was truly reflective of gait asymmetry. Determination of lameness would require determination of causation, including whether it is pain related.

Gait symmetry does not necessarily correlate to lameness, and because the participating horses were not given an exam, the study only notes gait asymmetry in their movement patterns.

Does Asymmetry Affect Performance?
Literature suggests that up to 77% of show jumpers and 82% of racehorses suffer lameness that sidelines them at some point during their career. But how much does gait asymmetry occur and how often does it affect performance? Dr. Contino and colleagues created a pilot study to determine the prevalence and magnitude of gait asymmetry in horses competing in eventing, show jumping and dressage. Correlation of performance with the level of gait asymmetry also was determined for each discipline.

Because horses were competing in Fédération Equestre Internationale events, they were assumed to be clean of performance-enhancing or nonsteroidal agents, per the FEI Clean Sports rules. All horses were voluntarily enrolled, and results were confidential but available after competition per owner request.
In-hand lameness exams were performed prior to start of competition and horses were subjectively graded for asymmetry according to a modified AAEP grading scale (0, sound; 5 non-weight bearing) by consensus opinion of 2 expert practitioners. A body-mounted Lameness Locator was also used as an objective measurement. The horses were evaluated in a straight line only, similar to what is used for the FEI jog evaluation. Each limb was graded, and the horses were given a grade for their most asymmetrical limb and a cumulative grade, which was simply the sum of the grades assigned to each limb. It should be noted that there is no gold standard for asymmetry—or lameness for that matter—evaluation.

Out of 299 total horses eligible for participation, 84 were included in the study. Most participating horses were from eventing (n=47) and were Warmbloods (n=54). Show jumpers had the highest voluntary participation with 58% (n=22) and dressage was the least with only 12% (15 horses). The average age was 11.6 years (range, 6-20 years).

Subjectively, 11% of all horses were symmetric, or sound, compared with 12% using objective measures. With subjective measures, 44% had multi-limb gait asymmetry; with objective measures, 51% had multi-limb gait asymmetry. Although the range of gait asymmetry was grade 0 to 3, the average gait asymmetry was grade 1 regardless of discipline, she said. Results were similar when looking at cumulative gait asymmetry, with a mean grade of 1.3 across disciplines.

Despite most of the horses having mild gait asymmetry, there was no correlation between gait asymmetry and placement in competition. Jumpers with asymmetry tended to perform better, while dressage horses tended to do worse, according to these unpublished data.

Although gait asymmetry was not shown to be performance limiting, Dr. Contino noted that this does not necessarily make it acceptable from a social licensing standpoint.

“Really what I’m hoping,” she told the AAEP audience, “is that this work springboards the idea that there are better ways to measure readiness to compete. We really should be looking more at the ridden horse pain ethogram and this new world of wearable technology.” MeV

For more information:
Dyson S. The ridden horse pain ethogram. Equine Vet Educ. 2022;34(7):372-380.

Egenvall A, Tranquille CA, Lönnell AC, et al. Days-lost to training and competition in relation to workload in 263 elite show-jumping horses in four European countries. Prev Vet Med. 2013;112(3-4):387-400.

Dyson PK, Jackson BF, Pfeiffer DU, et al. Days lost from training by two- and three-year-old Thoroughbred horses: A survey of seven UK training yards. Equine Vet J. 2008;40(7):650-657.