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2.2 Preparation
The tests were set up on a treadmill. This treadmill was set up in the veterinary clinic of the University of Ghent (Merelbeke), and a num ber of stables were connected to it.
The animals had never walked on a treadmill before; for this reason, it was decided to allow the study animals to walk on the treadmill for a quarter of an hour before the tests to allow them to become accustomed to it. This also allowed the horses to adopt their normal stride pattern.
After the study animals had been familiarised with the treadmill, identifying marks were applied to the animals. These were applied at the level of the tu ber coxae and the tu ber sacrale with an orange dye.
2.3 Recordings
The procedure consisted of two test days and three test sessions.
There was a time interval of 5 weeks between the two test days.
On test day 1, the study animals were analysed twice on the treadmill while walking. A first image analysis was performed during walking. After that, the horses were treated. After a half-hour wait, the animals again underwent an image analysis on the treadmill while walking (test session 2).
A 5-week interval was allowed between test day 1 and test day 2. On test day 2, another image analysis was performed of the study animals during walking (test session 3).
As far as possible, it was endeavoured to provide identical conditions for the first and second session day, so that the horses were subject to the least possible stress.
2.4 Setup
“Fixed points” were marked on the sides of the treadmill. These markings always had to appear in the picture during calibration and the recordings. These markings could be different for each camera. The markers serve as a reference if the camera itself had to move. The markings used were a piece of black tape with white tape above it.
In order to obtain optimal images, extra lighting was placed along both sides of the treadmill.
The rear-view camera was set up in line with the axis of the treadmill. This camera was connected via a coaxial cable to the video recorder which recorded the images.
The camera for the top view was set up above the treadmill. This was secured on a vertical construction in the air, so that the camera was perpendicular to the treadmill and the lumbar spinal column. These camera was connected via a coaxial cable to a second video recorder, to record the images.
Both recorders were connected to a monitor. In this way, the images could be checked during recording.
2.5 Processing of the results and statistical analysis
The video images were analysed using the Dartfish and SIMI Motion programs, successively from the qualitative and quantitative viewpoint. Next, for each study animal individually, it was examined whether there was a significant difference before and after treatment. Each of the test sessions was examined and processed. Finally, the study animals were assessed subjectively.
2.5.1 Qualitative analysis
The qualitative analysis was carried out via the Dartfish program. This was used to process, measure and compare the images in 2D.
The images on the video tapes were first digitized. Then the pictures were imported via the Dartfish program for further analysis.
2.5.2 Quantitative analysis
The quantitative analysis was performed via the SIMI Motion program. This enables image processing, and movements can be analysed comprehensively in 3D.
The images on the video tapes were first digitized. Then the images were imported via the Dartfish program for further analysis. From within Dartfish, the pictures were compressed so that they could be imported into the SIMI Motion program.
Via the SIMI Motion program, 3D-images could be processed. First of all, a specification had to be defined. Next, the cameras were set up and calibrated. The calibration cube was analysed in SIMI Motion. After that, the coordinates of the images, recorded via the cameras (rear view and top view), were converted into 3D.
The coordinates were ultimately calculated in 3D via the SIMI Motion program by placing manual points on each frame of the pictures on both tu ber coxae and on the middle of the spinal column at tu ber sacrale height. After all this had been done, the connections could be made in order to interpret the data.
Via the connections made by the SIMI Motion programme, the angles were calculated in Excel via trigonometry for both the angles (α) in the XY-plane (rear view camera) and for the angles (β) in the YZ-plane (top view camera).
2.5.3 Subjective analysis
The subjective analysis was obtained by interviewing the owners/riders of the study animals. They were asked about overall changes in the condition of the horse: welfare, manner, discipline, technical difficulties in riding. Then they were asked for a general assessment before and after treatment. The owners/riders had to give a score from 1 to 10, before and after treatment.
3. Results
3.1 Quantitative analysis
For the quantitative analysis, the coordinates both tu ber coxae of the study animals were used. By using these coordinates and trigonometry, the angle alpha in the XY-plane and the angle beta in the YZ-plane calculated between both tu ber coxae, over time.
Next the angles "before treatment" (BT), "30' after treatment" (AT) and "5 weeks after treatment" (AT2) are compared in a graphic. In the graphics, the pattern of the angles in degrees (°) is shown over time. From this, it can be concluded whether there is a more regular pattern in the tu ber coxae, which translates into a more symmetrical and regular stride pattern and/or there is a greater amplitude, which translates into a freer movement of the pelvis and the thoraco-lumbar spinal column.
The difference between the widest and narrowest angle is also shown in a table. These differences are compared for each of BT, AT and AT2. The greater the difference between the minimum and maximum angle, the freer the movement in the thoraco-lumbar spinal column and the pelvis.
Both from the graph and the table, a conclusion can be drawn in relation to the result on the movement of the thoraco-lumbar spinal column and the pelvis.
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