Head and pelvic movement symmetry in horses during circular motion and in rising trot.

The research study investigates the movement symmetry in horses during various types of motion, such as circular movement and rising trot, with the aim of establishing guideline values for asymmetry. This is essential for evidence-based decision-making in lameness examinations using quantitative sensor-based gait analysis.

Objective of the Study

• The goal of the study was to understand and quantify the movement symmetry in horses during different movement exercises. The researchers were particularly interested in the variations during unridden and ridden trot, both on a straight path and in circular motion.
• They hypothesized that the ‘asymmetrical loading’ caused by circular motion, rising trot, and a combination of the two would lead to systematic changes in movement symmetry.

Method and Results

• The study used 23 horses of varying age and height, and inertial measurement units were used to accurately assess the movement symmetry of vertical head and sacral (lower spine) movements in different trot situations (in-hand, on the lunge, and rising trot).
• The results showed significant variations in movement symmetry between straight line trot and ridden exercise on a circle, with changes being more pronounced for the head than the sacrum.
• The highest amount of asymmetry was observed during a rising trot on the circle. The symmetrical index for the head was 1.23 for the left rein and 0.83 for the right rein, while the symmetrical index for the sacrum was 0.84 for the left and 1.15 for the right.

Significance of the Findings

• The findings of the study indicate a significant change in movement symmetry between different exercise conditions, with the greatest asymmetry found during rising trot on the circle.
• These variations in movement symmetry were of a similar magnitude to those seen in horses presenting with mild lameness.
• These findings are critical for veterinarians and other equine practitioners, as it provides them with a quantitative, evidence-based guideline to assess lameness in horses and make informed decisions on their care and treatment.