Asymmetries of horses walking and trotting on treadmill with and without rider.
Authors: Byström Anna, Clayton Hilary M, Hernlund Elin, Roepstorff Lars, Rhodin Marie, Bragança Filipe S, Engell Maria T, van Weeren René, Weishaupt Michael A, Egenvall Agneta
Journal: Equine veterinary journal
Summary
# Editorial Summary: Movement Asymmetry in Ridden Versus Unridden Dressage Horses When high-level dressage horses move under saddle in a collected frame, they develop measurably greater left-right asymmetries than they exhibit at liberty—a finding that challenges assumptions about the naturalness of ridden movement in elite equestrian disciplines. Byström and colleagues assessed seven sound dressage horses on a treadmill at walk and trot using kinematic and kinetic measurements, comparing movement symmetry with and without a rider in a dressage frame. At walk, asymmetries increased significantly with rider: forelimb stance duration differed by 13 ms (ridden) versus 9 ms (unridden), with additional asymmetries evident in forelimb protraction, stance mechanics and vertical ground reaction forces. Trotting revealed even more pronounced effects, with asymmetries increasing in both forelimbs and hindlimbs, particularly in spinal motion at the thoracic and sacral vertebrae (T6 and S3), where dorsal-ventral excursions differed by up to 6 mm between ridden and unridden conditions. For practitioners, these findings suggest that apparent asymmetries in ridden movement may partly reflect the biomechanical constraints of the collected frame rather than pre-existing lateral imbalances, and that establishing unridden baseline movement patterns could improve assessment accuracy when evaluating lameness or performance issues.
Read the full abstract on PubMed
Practical Takeaways
- •Well-trained dressage horses naturally move with slightly more asymmetry when carrying a rider in a dressage frame, suggesting this may be a normal response to rider weight distribution and contact rather than a pathological condition
- •Assessment of movement symmetry should consider whether horses are evaluated ridden or unridden, as the conditions produce measurably different results and may affect lameness evaluations
- •Asymmetries at walk and trot are not consistently correlated, indicating that gait-specific factors influence symmetry and practitioners should assess both gaits independently
Key Findings
- •High-level dressage horses demonstrated significantly increased movement asymmetry when ridden in a dressage frame compared to unridden conditions at both walk and trot
- •At walk, five variables showed increased asymmetry when ridden, including forelimb stance duration (9 ms unridden vs 13 ms ridden; P=0.008) and stance protraction (P=0.004)
- •At trot, six variables were more asymmetrical when ridden, including forelimb stance duration (2.5 ms vs 3.8 ms; P=0.004) and S3 maximum displacement (6 mm vs 12 mm; P<0.001)
- •Only five variables showed significant associations between walk and trot asymmetries, with only three demonstrating positive correlations