Head and pelvic movement asymmetries at trot in riding horses in training and perceived as free from lameness by the owner.
Authors: Rhodin Marie, Egenvall Agneta, Haubro Andersen Pia, Pfau Thilo
Journal: PloS one
Summary
Rhodin and colleagues used body-mounted accelerometers to measure vertical head and pelvic movement in 222 Warmblood riding horses deemed sound by their owners, quantifying asymmetries during straight-line trot and lunging work. Of the 222 horses, 161 (72.5%) exhibited motion asymmetries exceeding previously established symmetry thresholds, with head displacement minimum values averaging 14.3 mm asymmetry and pelvic displacement maximum values averaging 6.5 mm—suggesting that substantial movement asymmetries are remarkably common in horses considered clinically normal. The researchers identified both contralateral (41 horses) and ipsilateral (49 horses) concurrent forelimb and hind limb asymmetries, and found a linear relationship between pelvic asymmetry measurements during straight-line trot and those recorded on the lunge with the affected limb positioned to the inside of the circle. Critically, the study leaves unresolved whether these objective asymmetries reflect genuine pain or orthopedic pathology, or represent normal functional variation. For practitioners, these findings emphasise that objective motion analysis can detect asymmetries invisible to the human eye in horses performing normally, but establishing the clinical significance of such measurements—and their relationship to current lameness or future injury—remains an essential gap requiring further investigation.
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Practical Takeaways
- •Most riding horses in work appear sound to their owners but demonstrate measurable asymmetries in movement; this suggests subclinical asymmetries are common and may warrant investigation before they progress to clinical lameness
- •Objective measurement tools can detect asymmetries invisible to the human eye, but the clinical significance (pain vs. mechanical vs. inconsequential) remains unknown—use these findings to inform targeted assessment rather than diagnose pathology
- •Asymmetries detected on straight lines correlated with lunge findings, suggesting consistent patterns that might guide focused veterinary or therapeutic examination of specific limbs
Key Findings
- •72.5% (161/222) of horses perceived as sound by owners exceeded symmetry thresholds for at least one variable during straight-line trot
- •Head displacement minimum asymmetry (HDmin) averaged 14.3 mm in 58 horses; head displacement maximum (HDmax) averaged 12.7 mm in 41 horses
- •Pelvic displacement minimum (PDmin) averaged 5.7 mm in 79 horses; pelvic displacement maximum (PDmax) averaged 6.5 mm in 87 horses
- •41 horses showed contralateral and 49 showed ipsilateral concurrent forelimb and hind limb asymmetries