Determination of the stiffness of the equine spine.
Authors: Schlacher C, Peham C, Licka T, Schobesberger H
Journal: Equine veterinary journal
Summary
# Editorial Summary: Determination of the stiffness of the equine spine Understanding the mechanical properties of the equine back is fundamental to developing accurate biomechanical models and explaining how back pathology develops, yet these properties remain poorly characterised in the literature. Schlacher and colleagues tested 14 dissected equine spines in a tensile testing machine, applying force to the dorsal spinous process of T12 across three loading directions—dorsoventral (neutral and rotated 30°) and laterolateral—until achieving 4 cm of movement in each plane. Dorsoventral stiffness averaged 2093 ± 611 N/m in neutral position and 2182 ± 459 N/m when the spine was rotated 30°, whilst laterolateral stiffness was significantly lower at 1454 ± 156 N/m, demonstrating that spinal stiffness varies markedly depending on the direction of loading. These directional differences in mechanical behaviour have important implications for understanding how repetitive loading patterns during work—particularly lateral movements and collection—may predispose certain regions of the back to injury, and suggest that rehabilitation and training strategies should account for the spine's directionally-dependent stiffness properties.
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Practical Takeaways
- •The equine spine resists lateral movement less effectively than vertical movement, which may influence how loading patterns contribute to back injury development
- •Understanding directional stiffness differences can inform assessment and treatment strategies for horses with back problems
- •Mechanical properties of the spine should be considered when evaluating saddle fit, rider balance, and training methods that may predispose to back disorders
Key Findings
- •Dorsoventral stiffness of the equine spine measured 2093 ± 611 N/m in nonrotated position and 2182 ± 459 N/m in 30-degree rotated position
- •Laterolateral stiffness was significantly lower than dorsoventral stiffness at 1454 ± 156 N/m
- •Spine stiffness is directionally dependent, varying with the direction of applied force and spinal position