Three-dimensional kinematics of the equine spine during canter.

This research analyses the 3-dimensional movements of a horse’s spine during a canter, particularly in thoracic, lumbar and sacral vertebrae. The goal was to expand the knowledge of equine kinematics beyond the usual walk or trot to include cantering.

Study Design and Method

• The study involved five Dutch Warmblood horses that were measured while cantering on a treadmill.
• In the horses’ vertebral column, Steinmann pins were inserted into eight dorsal spinous processes. These processes included thoracic (T), lumbar (L) and sacral (S) vertebrae, as well as both tubera coxae.
• Fours markers were securely attached to each pin to help obtain measurements.
• The data from these markers were utilized to calculate a rotation matrix. This matrix was then divided into three orthogonal rotations: flexion/extension (FE); lateral bending (LB), and axial rotation (AR).

Findings

• Among the three rotations, variability between horses was lowest for flexion/extension (FE), slightly higher for axial rotation (AR) and highest for lateral bending (LB).
• The maximal range of movement was, for flexion-extension, lateral bending, and axial rotation, 15.8 +/- 1.3 degrees, 5.2 +/- 0.7 degrees, and 7.8 +/- 1.2 degrees respectively.
• Regarding relative angles, the most significant flexion-extension motion occurred between the L5 and S3 vertebrae, with motion range values of up to 8.6 degrees.
• Simultaneous rotation of successive vertebrae was most prominent during the single support and suspension phases of the stride cycle, which improves spinal stability.
• It was observed for all rotations that the timing of vertebral rotations and the pro- and retraction of the limbs closely correlated.

Implication

• This study offers new insights into equine kinematics during a canter, an area that has been less explored in comparison to walks and trots.
• The analysis of the rotations and movements of the vertebrae helps create a clearer understanding of the biomechanics involved in a horse’s canter. These insights could potentially be leveraged in therapies and training protocols for performance horses, allowing for better care and performance optimization.