Associations between Racing Thoroughbred Movement Asymmetries and Racing and Training Direction.
Authors: Forbes, Ho, Parkes, Sepulveda Caviedes, Pfau, Martel
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Racing Direction and Gait Asymmetry in Thoroughbreds Unilateral training and racing surfaces may induce directional gait adaptations in Thoroughbreds, yet the relationship between track geometry and movement asymmetry had not been systematically quantified. Forbes and colleagues assessed 307 racing Thoroughbreds from two facilities using opposite track directions (anticlockwise in Singapore, clockwise in Hong Kong), employing inertial sensors on the head and pelvis during straight-line trotting to measure limb loading asymmetries with millimetre precision. The clockwise-training cohort exhibited significantly greater left forelimb asymmetries across multiple movement variables (minimum displacement, maximum displacement, and upward movement amplitude; all p < 0.03), whilst the anticlockwise group showed corresponding right-sided asymmetries, with pelvis kinematics mirroring these directional patterns. These findings suggest that repeated unilateral loading during training and racing produces measurable gait compensations in the 'outside' limbs, implying that practitioners should assess asymmetry directionality within the context of each horse's training environment, and that periodic training in alternate directions may help mitigate one-sided musculoskeletal adaptations that could predispose to injury.
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Practical Takeaways
- •Training and racing predominantly in one direction induces measurable, directional gait asymmetries in Thoroughbreds; consider varying training direction to promote symmetrical movement
- •Clockwise-trained horses show left-sided movement asymmetry while anticlockwise-trained horses show right-sided asymmetry, suggesting the 'outside' limb bears reduced load—monitor for uneven wear patterns and musculoskeletal compensation
- •Gait assessment using inertial sensors can objectively quantify these asymmetries (≥5mm threshold) to identify at-risk horses and guide training modifications to reduce injury risk
Key Findings
- •Horses training clockwise (HKJC) showed significantly more left forelimb asymmetry compared to anticlockwise-training horses (STC), with head MinDiff p<0.0001, MaxDiff p=0.03, UpDiff p=0.01
- •Pelvis MinDiff (p=0.010) and UpDiff (p=0.021) differed significantly between cohorts, with HKJC showing left fore- and hindlimb asymmetry and STC showing right asymmetry
- •Gait asymmetry direction appears to be adaptively related to predominant racing direction, reflecting reduced 'outside' limb loading patterns