Differential rotational movement and symmetry values of the thoracolumbosacral region in high-level dressage horses when trotting.
Authors: MacKechnie-Guire, Pfau
Journal: PloS one
Summary
# Editorial Summary MacKechnie-Guire and Pfau's 2021 kinematic analysis of ten Grand Prix dressage horses revealed substantial differences in spinal movement patterns between in-hand trotting and ridden sitting trot, using inertial sensors positioned along the thoracic and lumbar spine to quantify three-dimensional rotational movement. When carrying a rider in sitting trot, horses demonstrated significantly increased pitch (flexion–extension) and roll (lateral bending) in the caudal thoracic and lumbar regions (T18–L3), with pitch angles rising from 3.9° to 6.3° and roll increasing from 7.7° to 11.6°, whilst heading values (rotational twist) nearly doubled from 4.2° to 9.5°—conversely, cranial thoracic mobility (T5–T13) was restricted, with heading values declining from 7.1° to 5.2°. These findings demonstrate that rider weight in sitting trot fundamentally alters thoracolumbosacral mechanics, shifting movement demand caudally and constraining cranial spinal rotation, which has important implications for performance assessment and lameness investigations. Practitioners evaluating dressage horses presenting with loss of performance should assess movement under saddle rather than relying solely on in-hand evaluation, as the ridden condition produces materially different spinal kinematics that may mask or reveal underlying dysfunction in force transmission between limbs and the trunk.
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Practical Takeaways
- •When evaluating horses for performance issues or lameness, assessment under saddle in sitting trot is essential as spinal kinematics differ significantly from in-hand trotting—in-hand evaluation alone may miss relevant biomechanical changes
- •The caudal thoracic and lumbar spine shows substantially increased motion (pitch and roll) when carrying a rider, which may be relevant to identifying areas of compensation or restriction affecting performance
- •Reduced lateral bending in the cranial thoracic region under saddle suggests the rider's weight redistributes spinal mechanics; this should be considered when assessing symmetry and movement quality in dressage horses
Key Findings
- •Sitting trot increased pitch angles in caudal thoracic-lumbar region from 3.9° to 6.3° compared to in-hand trotting (P<0.0001)
- •Roll angles in caudal thoracic-lumbar spine increased from 7.7° to 11.6° in sitting trot versus in-hand (P=0.003)
- •Heading values decreased in cranial thoracic region (T5-T13) from 7.1° to 5.2° when ridden in sitting trot (P=0.01), indicating reduced lateral bending
- •Rider weight in sitting trot significantly alters thoracolumbosacral kinematics, emphasizing the importance of assessing horses during ridden exercise rather than in-hand only