Thoracolumbar movement in sound horses trotting in straight lines in hand and on the lunge and the relationship with hind limb symmetry or asymmetry.
Authors: Greve L, Pfau T, Dyson S
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: Thoracolumbar Movement in Straight Lines versus Circles Whilst equine practitioners recognise that turning alters movement mechanics, the specific kinematic changes occurring in the thoracolumbar spine during circular work have remained poorly documented. Greve, Pfau and Dyson used inertial sensors placed at six spinal landmarks (withers through sacrum) to measure three-dimensional movement in fourteen sound horses trotted both in straight lines and on the lunge in both directions, simultaneously assessing hindlimb symmetry through gait analysis. Lunging induced measurably greater spinal movement compared with straight-line work, including increased flexion-extension range (>1.3°), lateral bending (>16°), and lateral translation (>16 mm), alongside significantly greater asymmetry in dorsoventral movement within each stride (9±6% versus 6±6%). Notably, the circle-induced movement pattern resembled an inside hindlimb lameness and correlated significantly with the increased asymmetry in thoracolumbar dorsoventral movement, suggesting the spine responds predictably to the biomechanical demands of turning. For practitioners, these findings clarify that apparent gait asymmetries or subtle movement changes observed during lunging may represent normal adaptive mechanics rather than pathology, yet also highlight that repetitive lunging, particularly on one rein, could impose asymmetrical loading on the thoracolumbar region—relevant considerations for training prescription, rehabilitation planning, and lameness diagnosis.
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Practical Takeaways
- •Lunging and circular work naturally alter spinal movement patterns in sound horses—this is biomechanically normal, not necessarily pathological, but should inform how you interpret asymmetry observations during assessment
- •When evaluating a horse with suspected hind limb lameness, note that circles create movement patterns resembling inside hind limb asymmetry; always compare straight-line movement to circle movement to differentiate true lameness from circle-induced changes
- •The thoracolumbar region (especially T13) shows the greatest movement compensation during circles; consider this when designing rehabilitation or training programs for horses with back or hindlimb issues
Key Findings
- •Circles induced greater asymmetry in dorsoventral thoracolumbar movement (9±6%) compared to straight lines (6±6%)
- •Maximum dorsoventral movement amplitude occurred at T13 (119±14 mm straight vs. 126±20 mm circles)
- •Circle work induced significantly greater flexion-extension ROM (>1.3°), lateral bending (>16°), and lateral motion (>16 mm) than straight-line trotting
- •Circle-induced thoracolumbar movement patterns were significantly associated with alterations in hindlimb gait symmetry (P=0.03)