Influence of the load of a rider or of a region with increased stiffness on the equine back: a modelling study.
Authors: Peham C, Schobesberger H
Journal: Equine veterinary journal
Summary
# Editorial Summary Peham and Schobesberger used biomechanical modelling to quantify how rider load and regional muscle stiffness affect forces and torques throughout the equine spine, employing kinetic, kinematic and electromyographic data from 15 sound horses to build computational simulations in ADAMS software. Vertical forces increased progressively with gait speed under saddle (walk 3.83 N/kg, trot 5.18 N/kg, gallop 5.60 N/kg), whilst transversal forces remained largely unchanged between ridden and unridden conditions. Most striking were the dramatic torque increases distal to regions of localised stiffness: lateral bending torques amplified five-fold in walk (342 to 1723 Nm) and 2.5-fold in trot (393 to 1004 Nm), whilst dorsoventral torques escalated nearly ten-fold in walk (386 to 3705 Nm) and proportionally in trot (458 to 4340 Nm). The findings suggest that pathological stiffening—such as muscle tension, arthritis or trauma affecting a single spinal region—generates substantially greater mechanical stress than normal ridden work, indicating that identifying and addressing localised dysfunction rather than attributing all back pain to rider load alone should be a clinical priority for veterinarians and physiotherapists managing equine back disease.
Read the full abstract on PubMed
Practical Takeaways
- •Back stiffness or muscle tension in one region creates disproportionately high forces in adjacent segments, potentially explaining why localized back problems can develop into widespread issues
- •A rider's weight alone causes less spinal stress than musculoskeletal dysfunction, suggesting that training and fitness management may be more important than rider weight for back health
- •Assessment and treatment should target stiffness and reduced mobility as early signs of developing back pathology, before they cause cascading damage to adjacent segments
Key Findings
- •Vertical forces from rider weight increase from 3.83 N/kg at walk to 5.60 N/kg at gallop, with no significant changes in transversal forces between ridden and unridden horses
- •Localised increased stiffness in the back causes profound torque increases in the adjacent segment: lateral peak torques increase 5-fold in walk and 2.5-fold in trot
- •Dorsoventral torques increase dramatically with localised stiffness, from 386 to 3705 Nm in walk and 458 to 4340 Nm in trot
- •Pathological processes such as partial increased back stiffness impose greater stress on the equine spine than rider load alone