Video analysis is now an essential tool in the evaluation of elite athletes, both for performance enhancement and health management. As a result, video analysis is now commonly considered as an essential component of the athlete’s support team.
In equine veterinary medicine, video images allow, among other things, to see joint movements in more detail, to measure them and to quantify them. In fact, several factors can influence perception when evaluating a horse’s locomotion, such as the presence of fur, which makes it difficult to appreciate joint movements in the lower limb area.
But how do veterinarians and researchers use this technique? How can video recording, correlated with the quantification of locomotion, support veterinary diagnosis?
Kinematic analysis of horse locomotion
The first kinematic studies of horse locomotion were conducted in the nineteenth century. At that time, the possibilities offered by photography – and more particularly by chronophotography – allowed scientists to exploit new techniques. In the 1870s, Marey and Muybridge used these methods to decompose horse movement. By bringing together several sequences, they were able to “stop the movement” of the horse, and see with accuracy some details not perceptible to the naked eye! Their main discovery is the horse’s suspension time during the canter, when none of the four limbs touch the ground.
Many studies on horse locomotion have been conducted since then, evaluating the correlation between the veterinary diagnosis made after a live assessment and the one made after a video assessment.
In 2014, Rungsri and al demonstrate that during video evaluation, the diagnostic agreement was moderate for experienced veterinarians – 74% (k=0.52) – and moderate experienced – 70% (k=0.48) – but low for the intern group – 67% (k=0.40). In conclusion, the study found that expectation bias, which can sometimes affect perception, is higher in a live assessment than in a video assessment.
A few years later, Hardeman et al’s (2020) study, also found that the relationship between the degree of lameness and objective asymmetry differed slightly between veterinarians for live and video evaluations. Although there were statistically significant differences between subjective grading and objective measures when comparing live and video evaluations, the results of the live and video evaluations remained similar from a practical standpoint. For example, a forelimb lameness of the same grade, corresponded to 36 mm during the video assessment versus 29 mm during the live evaluation. These findings imply that high-quality video could be a viable method for retrospective examinations. This is a significant discovery: video review enables veterinarians to calibrate their subjective assessments in relation to the objective analysis or subjective assessments of their colleagues, and/or to obtain or provide a second opinion in complex cases. Another important finding from this study is that high-quality videos can be an essential component of clinical documentation. Particularly in the field of education, videos associated with quantitative locomotion analysis could be useful in learning how to recognize and classify lameness during an orthopedic examination.
Veterinary diagnosis: what are the benefits of video analysis?
Video recording is definitely a technique that should not be forgotten to support the veterinary diagnosis. For example, to see an asymmetry of protraction, video is essential, since the horse has a very fast locomotion (a stride = 0.5 seconds, a stance time = a tenth of a second). In order to establish a diagnosis, it is therefore necessary to be able to correctly assess the changes that take place in such a short time. For this purpose, video is a valuable support with many advantages:
- Diagnostic optimization – Video recording allows the study of the horse’s normal and abnormal locomotion, in particular by focusing retrospectively on a given area. Indeed, it is impossible when a horse is moving to focus instantly on the different parts of its body. During the veterinary examination, it may be useful to film the horse’s locomotion from a different angle than the veterinarian in order to perform a thorough analysis of the locomotion, from the side and/or from the front and/or from three quarters.
- Detection of non visible phenomena – By allowing to focus on the movements zone by zone, the video analysis allows to see phenomena invisible to the naked eye.More broadly, the video’s ability to be slowed down allows for the decomposition of protraction / stance / propulsion mechanisms, articular flexion / extension movements, and various muscular mechanics. For example, the flexion movements of the lower limb joints in motion are not visible to the naked eye.
- Analysis of circle movements – The horse’s locomotion in a circle is a complex task to interpret. It is not easy since it requires a 3D analysis to understand how the horse is able to coordinate its different muscle groups..
- Sharing exams – When a locomotor examination is filmed, the examination can be reviewed at any time and without restriction. This can be very useful for clarifying doubts or comparing two exams – before/after a treatment – before/after a winter break… It can also allow you to ask a colleague for an opinion, without any time limit or geographical constraints.
- Veterinary education and training – According to Hardeman’s study, video storage of locomotor examination, correlated with locomotion quantification, is a significant added value for veterinary training. It allows students or young professionals to practice at any time, to train their eye for the complex exercise of diagnosing and evaluating limping. This pedagogical approach, when combined with e-learning modules, may become indispensable in the coming years.
The use of video analysis on a larger scale, always correlated with veterinary expertise, will help make the diagnosis and treatment of locomotor asymmetries even more accurate. Coupled with locomotion quantification data, video assessment is a key component for documentation, communication between veterinarians, and student education.
LA (2020). Locomotion équine au ralenti, et techniques d’analyse du mouvement. Dailymotion. Available at: https://www.dailymotion.com/video/x7q9xy1
Rousseau, R., Frey, A., Chiquet, L., Rousseau, D., Sene, J.-M. ., Deviere, F. and Vesselle, B. (2017). Analyse vidéo et traumatismes en compétition de judo de haut niveau : étude pilote. Journal de Traumatologie du Sport, 34(3), pp.161–167. doi:10.1016/j.jts.2017.06.002.
Hardeman, A.M., Egenvall, A., Serra Bragança, F.M., Swagemakers, J., Koene, M.H.W., Roepstorff, L., Weeren, R. and Byström, A. (2022). Visual lameness assessment in comparison to quantitative gait analysis data in horses. Equine Veterinary Journal, 10. doi:10.1111/evj.13545.
Keywords: video analysis, veterinary diagnosis, veterinary activity, veterinary practice, locomotor asymmetry, lameness, locomotion quantification tool, EnvA, CIRALE