Shear ground reaction force variation among equine arena surfaces.
Authors: Rohlf C M, Garcia T C, Fyhrie D P, le Jeune S S, Peterson M L, Stover S M
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: Shear Ground Reaction Force Variation Among Equine Arena Surfaces Understanding how different arena surfaces behave mechanically is essential for managing injury risk, as shear forces at the hoof-surface interface directly influence grip, hoof slide, and the forces transmitted through the limb. Rohlf and colleagues measured shear ground reaction forces across twelve arena surfaces (five dirt and seven synthetic) whilst simultaneously analysing composition, temperature, cushion depth, and moisture content to identify which factors most significantly affect grip and stability. Contrary to expectations, shear properties showed no meaningful difference between dirt and synthetic categories overall; instead, fibre content emerged as a critical determinant—higher fibre content reduced soil adhesion (r = −0.75) but substantially increased coefficient of friction (r = 0.81). Cushion depth and moisture content also influenced maximum shear force significantly, with thicker, wetter surfaces generating greater shear forces, suggesting that routine surface management practices directly shape the mechanical demands placed on the equine musculoskeletal system. For farriers, physiotherapists, and facility managers, these findings indicate that injury prevention and performance optimisation depend less on choosing between dirt or synthetic materials and more on actively managing fibre composition and moisture levels—controllable variables that can be adjusted to meet the specific needs of training, rehabilitation, or competition.
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Practical Takeaways
- •Arena owners can modify shear forces and hoof grip by adjusting fiber content, cushion depth, and moisture—providing practical levers for injury prevention without replacing entire surfaces
- •Adding fiber to surfaces increases traction (friction) but reduces adhesion, which may benefit horses prone to slipping while reducing suction-related injuries
- •Monitor and maintain optimal moisture levels and cushion depth tailored to your facility's needs, as these directly impact the forces transmitted through the hoof and limb
Key Findings
- •Shear properties are not significantly different between dirt and synthetic surface categories, but fiber content correlates with adhesion and friction properties
- •Increased fiber content decreases soil adhesion (r = -0.75) and increases coefficient of friction (r = 0.81)
- •Maximum shear force increases significantly with cushion depth (r = 0.61) and moisture content (r = 0.57)
- •Surface composition and management properties have greater influence on shear mechanics than broad material classification (dirt vs. synthetic)