The Effect of Tree Width on Thoracolumbar and Limb Kinematics, Saddle Pressure Distribution, and Thoracolumbar Dimensions in Sports Horses in Trot and Canter.
Authors: MacKechnie-Guire Russell, MacKechnie-Guire Erik, Fairfax Vanessa, Fisher Diana, Fisher Mark, Pfau Thilo
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Saddle fit profoundly influences spinal mechanics and pressure distribution, yet the precise effects of tree width adjustments remain poorly characterised in the literature. Researchers equipped 14 sports horses with motion capture markers, inertial measurement units, and pressure-sensing technology to compare their kinematics and soft-tissue responses across three saddle widths—correctly fitted, one size wider, and one size narrower—during both trot and canter. Undersized saddles generated concerning pressure concentrations in the caudal region (14% increase in peak pressure) alongside reduced segmental mobility at T13 in multiple planes, whilst oversized saddles shifted load cranially and compressed thoracolumbar musculature dimensions by 14% at T13 during trot. In canter, width mismatches altered axial rotation patterns across the thoracolumbar spine, with the wide saddle paradoxically reducing rotation at T5 but increasing it at T13 and L3, suggesting compensatory movement patterns. These biomechanical disruptions—detectable through objective measurement even when not visibly apparent—underscore that correct tree width is not merely a matter of comfort but a fundamental requirement for preserving normal spinal kinematics and preventing pressure-related tissue damage. Farriers, veterinarians, and coaches should prioritise professional saddle fitting assessment, particularly when horses show changes in performance or gait quality, since incremental deviations from proper fit accumulate pathological consequences.
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Practical Takeaways
- •Saddle width matters: even small deviations from correct fit alter spinal movement and pressure distribution, potentially affecting performance and comfort
- •Wide saddles concentrate pressure cranially and reduce spinal mobility at T13; narrow saddles concentrate pressure caudally—both compromise movement
- •Proper saddle fitting by a qualified fitter is not cosmetic but biomechanically critical for maintaining normal locomotor patterns in sports horses
Key Findings
- •Wide saddles increased peak cranial pressure by 8.5% and reduced T13 thoracolumbar dimensions by 14% in trot
- •Narrow saddles increased caudal peak pressures by 14% and reduced T13 mediolateral range of motion by 8% in trot
- •In canter, wide saddles decreased axial rotation by 1% at T5 but increased it by 5% at T13 and L3
- •Saddle fit significantly affects thoracolumbar kinematics and pressure distribution, indicating correct fitting is essential for unhindered locomotion