The effect of collection and extension on tarsal flexion and fetlock extension at trot.
Authors: Walker V A, Walters J M, Griffith L, Murray R C
Journal: Equine veterinary journal
Summary
# Editorial Summary: Collection, Extension and Tarsal Loading in Dressage Horses Walker and colleagues used high-speed video and inertial motion sensors to examine how different gaits influence hindlimb biomechanics in four dressage horses, measuring tarsal flexion during stance and fetlock extension across collected and extended trot on three surfaces (waxed outdoor, sand/plastic, and waxed indoor). Contrary to common assumptions, collected trot produced significantly *less* tarsal flexion and fetlock extension than extended trot, despite its slower speed and longer stride duration, suggesting that extended trot may actually impose greater loading on the suspensory ligament rather than collected work. Given the high incidence of suspensory ligament injury in horses trained for extravagant movement, these findings propose that repetitive extended trot—particularly in young competition horses—could be a meaningful risk factor for developing suspensory desmitis. The practical implication is that training programmes emphasising extended gaits warrant careful management of volume and intensity, and that periodising work to include shorter durations of extension, varied surfaces, and adequate recovery may help mitigate injury risk in horses selected for dressage or other disciplines requiring flashy movement.
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Practical Takeaways
- •Extended trot training may be a risk factor for suspensory ligament injury in dressage horses; consider balancing extravagant movement work with appropriate rest and conditioning
- •Horses performing collected trot may experience different biomechanical loading patterns than extended trot, which could inform training programme design and injury prevention strategies
- •Young horses undertaking repetitive extended trot work for extravagant movement may warrant closer monitoring for early signs of suspensory desmitis
Key Findings
- •Collected trot showed significantly lower speed, stride length, and longer stride duration compared to extended trot across all surfaces
- •All horses demonstrated less tarsal flexion and fetlock extension in collected versus extended trot (P<0.05)
- •Reduced tarsal flexion and fetlock extension in collected trot likely increases suspensory ligament loading
- •Extended trot may increase suspensory ligament strain, providing a possible explanation for high incidence of suspensory ligament injury in horses trained for extravagant movement