The effects of rider size and saddle fit for horse and rider on forces and pressure distribution under saddles: A pilot study
Authors: Roost L., Ellis A. D., Morris C., Bondi A., Gandy E. A., Harris P., Dyson S.
Journal: Equine Veterinary Education
Summary
# Editorial Summary Whilst anecdotal evidence suggests that oversized riders compromise equine welfare, robust scientific data quantifying the biomechanical effects of rider weight on pressure distribution under the saddle remain scarce. Roost and colleagues conducted a prospective crossover trial in which six horses in regular work were ridden by four riders of similar ability but stratified by bodyweight-to-horse-weight ratios (light <12%, moderate 12–15%, heavy 15–18%, very heavy >20%) whilst wearing a calibrated force-sensing mat; the researchers recorded pressure magnitude and distribution across three gaits and assessed real-time lameness and behavioural indicators, abandoning any test if grade 3 or above lameness emerged. Very heavy riders demonstrated substantially altered biomechanics—their seat extended beyond the saddle cantle at walk, their heels positioned cranially to the hip joints at trot and canter—and generated significantly higher pressures in the caudal saddle region at walk and the highest peak pressures overall during canter; notably, all 13 very heavy and one moderate rider test was abandoned due to lameness or behavioural concerns, whereas lighter riders produced more symmetrical cranial pressure distribution at rising trot. These findings suggest that excessive rider size not only compromises postural stability and saddle fit but generates abnormal pressure patterns that may precipitate musculoskeletal pain, making careful assessment of the rider-saddle-horse interaction essential for all equine professionals involved in performance or remedial work.
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Practical Takeaways
- •Rider weight relative to horse (aim for <15% ratio) significantly affects saddle pressure and lameness risk; very heavy riders should reconsider their mounts or expect musculoskeletal consequences.
- •Saddle fit must accommodate both horse and rider anatomy—poor fit in heavier riders results in abnormal pressure patterns that correlate with lameness and behavioral problems during work.
- •Monitor horses ridden by heavier riders closely for early lameness and behavioral changes, as pressure distribution becomes problematic and may develop into musculoskeletal pain.
Key Findings
- •Very heavy riders (>20% body weight ratio) produced significantly higher maximum peak pressures in canter and abnormal pressure distribution in all gaits compared to lighter riders.
- •13 of 13 tests with heavy (>15-18%) and very heavy riders were abandoned due to lameness or behavioral issues, versus only 1 of 12 moderate weight tests.
- •Very heavy rider seat extended beyond saddle cantle and heels positioned cranial to tubera coxae, indicating poor saddle fit and rider position.
- •At rising trot, lighter to heavy riders showed higher cranial pressures while very heavy riders showed similar caudal-cranial pressure distribution, suggesting compromised weight distribution.