Dynamic properties of a dirt and a synthetic equine racetrack surface measured by a track-testing device.
Authors: Setterbo J J, Fyhrie P B, Hubbard M, Upadhyaya S K, Stover S M
Journal: Equine veterinary journal
Summary
# Editorial Summary: Dynamic Properties of Dirt and Synthetic Equine Racetrack Surfaces Racetrack surface engineering represents a modifiable risk factor in Thoroughbred racehorse injury prevention, yet quantifying how different surfaces respond to the impact forces generated during galloping has proved challenging. Setterbo and colleagues deployed a specialised track-testing device that replicated equine hoof impact at varying velocities (1.91–2.63 m/s), impact angles (vertical and 20° lateral), and across consecutive impacts, measuring force transmission, displacement and material stiffness in both dirt and synthetic racing surfaces. The synthetic surface demonstrated substantially lower mechanical reactivity across most parameters, with maximum forces, load rates and stiffness values ranging from 37–67% of those recorded in dirt surfaces; importantly, both surface types exhibited progressive stiffening with repeated impacts and higher velocities, suggesting active surface degradation through a training session or race day. These findings carry direct implications for track management protocols: the dramatic hardening of both surfaces following initial impacts emphasises the critical importance of regular maintenance and harrowing, whilst the persistence of surface property differences across the velocity range experienced during high-speed work indicates that softer synthetic surfaces will maintain their biomechanical advantages even during racing speeds. Practitioners and track managers should consider coordinating intensive training schedules to avoid repeatedly loading already-compacted surfaces, particularly given the research's clear demonstration that precompacted conditions substantially alter the shock-absorption characteristics horses experience with each stride.
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Practical Takeaways
- •Track managers should prioritize regular maintenance and grooming to prevent surface compaction, as repeat impacts significantly harden both dirt and synthetic surfaces—particularly critical before high-speed training sessions
- •Synthetic surfaces are mechanistically softer and may offer reduced impact loading compared to dirt, but this advantage diminishes with pre-compaction from prior use
- •Trainers should schedule high-speed work on freshly maintained surfaces rather than pre-trampled tracks to minimize injury risk from increased surface hardness
Key Findings
- •Synthetic racetrack surfaces produced 37-67% of the maximum forces, load rates, and stiffnesses measured in dirt surfaces
- •Both surfaces demonstrated reduced stiffness with lower impact velocities, angled impacts, and initial impacts compared to repeat impacts
- •Repeat impacts caused greatly increased hardness in both surface types, emphasizing the critical importance of track maintenance
- •Surface mechanical property differences between dirt and synthetic persist and increase at higher impact velocities relevant to racing speeds