Response of the Thoroughbred Forelimb to Perturbations Caused by a Change in Ground Surface.
Authors: Bardin Alienor L, Taylor Nila C, Robert Colborne G
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Forelimb Response to Track Surface Changes in Thoroughbreds Musculoskeletal injury remains a significant cause of morbidity and retirement in racing Thoroughbreds, with track surface properties—particularly hardness and consistency—recognised as important aetiological factors. Bardin and colleagues used a validated AnyBody musculoskeletal model informed by CT imaging, tissue properties, and kinematic data from five ridden Thoroughbreds to investigate how the forelimb responds acutely to perturbations caused by harder and softer ground surfaces encountered during trot and canter. When horses encountered a hard surface, the proximal limb became more compliant at both gaits, evidenced by increased shoulder flexion in the perturbed stance and increased elbow and carpal flexion during the following swing phase, whilst suspensory ligaments experienced reduced strain but the lacertus fibrosus was more heavily loaded. The soft surface perturbation produced more nuanced responses: at trot it increased strain on the deep digital flexor tendon and lacertus fibrosus, whilst at canter it initially protected suspensory structures but increased strain during the subsequent stance phase. These findings demonstrate that surface-induced perturbations affect biomechanical loading not only during the perturbed stance phase but propagate into subsequent locomotor cycles, suggesting that inconsistent or poorly maintained track surfaces may accumulate injury risk through altered strain patterns across multiple structures and gait phases—information of particular relevance when evaluating track conditions and injury prevention strategies.
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Practical Takeaways
- •Track surface hardness and consistency directly alter forelimb loading patterns and tissue strain in ways that extend beyond the immediate perturbation—consider long-term cumulative effects when managing training surfaces
- •Different gaits respond differently to surface changes (trot vs. canter), suggesting training schedules and surface selection should account for gait-specific injury risk profiles
- •Monitoring and maintaining consistent track surface quality may reduce musculoskeletal injury risk by preventing acute compensatory loading patterns in suspensory ligaments and digital flexor tendons
Key Findings
- •Hard surface perturbations increased proximal limb compliance with greater shoulder, elbow, and carpal flexion while reducing suspensory ligament strain but increasing lacertus fibrosus strain
- •Soft surface perturbations at trot increased coffin joint flexion and elbow extension in the perturbed stance phase, elevating strain to DDF and extensor structures
- •Surface changes affect biomechanics not only during the perturbed stance phase but also significantly influence the subsequent stance phase
- •Musculoskeletal modeling can predict differential tissue strain responses to track surface variations at different gaits