Home 9 Locomotion analysis 9 How to measure the evolution of the horse’s locomotion?

The horse’s locomotion is constantly changing during its life. With musculature, flexibility exercises, good nutrition, and many other factors, the horse’s locomotion can be improved. On the other hand, a lack of exercise, deficiencies, advanced age, joint degeneration or pain/injuries can affect its locomotion.

It is possible to measure a horse’s general health by analyzing how he moves. A horse with no dysfunction in its locomotor system is considered healthy: it has no pain or mechanical or neurological changes when performing its physiological movements. A decline in locomotion is a symptom that must be evaluated and managed to avoid exacerbation.

Locomotion quantification systems enable the storage of different locomotion exams over time, providing an objective and quantifiable record of previous exams. This article explains how to use EQUISYM to compare examination conditions quickly and easily in order to monitor changes in locomotion.

Evaluate horse’s locomotion: compare exams conditions 

1. Strides condition

To assess the effects of a condition, curves and indices can be analyzed, but standard deviation indicators can also be displayed, and a video synchronized with the quantified results can be viewed.

CURVES & STANDARD DEVIATIONS

Below, the curves represent an average of the strides taken during the condition related to the vertical displacement of the trunk – withers and pelvis – and the head. As the trot is a symmetrical gait, these vertical displacements are translated by sinusoidal curves, each sinusoid representing a half stride i.e. each sinusoid corresponds to a diagonal.

horse's locomotion

The main curve represents the average of the strides, while the less opaque band represents the variation of movement overall strides. A healthy horse will have mostly regular sinusoids and indices close to the centerline (0% = perfect symmetry).

Each stride of the condition can also be visualized separately. The screen shows several curves as well as the scattering of the various indices for each stride. 

horse's locomotion

PARAMETERS

The application measure three key parameters for reading the vertical displacements: amplitude of elevation, maximum of altitude, and minimum of altitude.

    • The amplitude of elevation represents the difference in elevation between the lowest and highest points of each sinusoid (curve), which is the total amplitude of elevation traveled by the neck, withers, and pelvis during and after limb propulsion. This indicator can reveal a horse’s lack of symmetry and, as a result, a lack of vertical propulsion or damping on a limb.

    • The MAX corresponds to the highest points of each sinusoid (curve) during the swing phase, i.e. the maximum elevation of the neck, withers, and pelvis following upward propulsion. This indicator can reveal a defect in head or trunk elevation.

    • The MIN  corresponds to the lowest points of each sinusoid (curve) when the limb is bearing down, i.e. the maximum descent of the neck, withers, and pelvis when bearing down on a diagonal. This indicator may reveal a lack of weight-bearing/damping.

These different parameters are supplemented by the asymmetry indices, in percentages. They range from -100% to +100%. The zone [-100% ; 0%[ represents the horse’s left side, the pink zone. If the indices are in this range, it suggests an asymmetry default on this side. The blue area ]0% ; +100%] includes asymmetries caused by a right-side default. Perfect symmetry is synthesized by an index at 0%.

It is essential to contextualize each data interpretation because many factors, such as the type of ground, the figure performed, or even the horse’s speed and reactions, can influence the variations…

VIDEO SYNCHRONIZATION

EQUISYM also allows to synchronize the condition video with the quantified data: it is possible to view the curves and the averaged indices simultaneously. The video can be paused, sped up, or slowed down.

equisym

2. Different conditions

It is possible to compare up to five conditions at the same time within the same examination. This permits to identify, among other things, the figures or grounds that highlight asymmetries or the positivity to a flexion test…EQUISYM system allows to easily quantify and classify the conditions according to the intensity of their clinical manifestations. Some conditions, such as the circle, will naturally induce asymmetries (whether they are accentuated or diminished), and this must be considered when analyzing the various indices.

TYPICAL EXAMINATION ANALYSIS

During a traditional locomotor exam, the data is usually analyzed as follows:

    • Straight line.
    • Comparison of the straight line with the flexion tests. Possibility of dissociating the comparison of forelimb and hindlimb flexion tests. It is relevant to complete the analysis of the positive flexion tests with the video synchronization to see the results stride by stride.
    • Comparison of circles for both rein on the same floor.
    • Comparison of circles for each rein on different types of floor.

Evaluate horse’s locomotion: compare exams between them

When monitoring the evolution of a horse’s locomotion over time, two questions are frequently asked: Is his locomotion improving? Or is it getting worse?  To answer these questions, it is possible to compare several conditions during different examinations, at any time!

1. Different periods of time

EQUISYM provides an objective assessment of changes in locomotion over time. This application corresponds to the longitudinal monitoring of the horse’s locomotion, which is useful for a variety of reasons, including sport horse rehabilitation, prevention (early diagnosis, injury prevention), treatment or shoeing follow-up, …

2. Same date

Comparisons of exams performed on the same day are useful for evaluating diagnostic anesthesia or a change in warm locomotion… Horse Y has a pronounced right diagonal amplitude default, with a -46 % left hindlimb default. The asymmetry is emphasized on the left-rein circle, on soft ground.

horse's locomotion

During the exam, two diagnostic anesthesias were performed: negative low plantar nerve block anesthesia and peroneal & tibial nerve block anesthesia. By comparing the spontaneous locomotion data and those of the peroneal & tibial nerve block anesthesia, we note that the percentages of asymmetry have improved significantly. A defect in the right diagonal remains visible, but asymmetry has been reduced by 14% and 35% for the withers and pelvis.

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CONCLUSION

The objective quantification of the data and their classification allows comparing, without time constraint, various examinations and conditions. Thus, improvements or deteriorations in locomotion can be highlighted following a flexion test, diagnostic anesthesia, a month of rehabilitation, a competitive season, and so on.

On a daily basis, the EQUISYM tool assists veterinarians in refining and specifying the diagnosis of locomotor asymmetries without cognitive bias. The vertical movements of the horse are transferred onto the tablet for intuitive and direct reading of the locomotor examination results.

Keywords: horse’s locomotion, locomotor asymmetries, lameness, equine veterinarians, diagnosis, clinical examination, EnvA

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