The effects of rider size and saddle fit for horse and rider on forces and pressure distribution under saddles: A pilot study
Authors: L. Roost, A. Ellis, C. Morris, A. Bondi, E. A. Gandy, P. Harris, S. Dyson
Journal: Equine Veterinary Education
Summary
# Editorial Summary When a rider's bodyweight exceeds 15–20% of the horse's bodyweight, pressure distribution under the saddle becomes markedly abnormal and frequently leads to acute lameness or behavioural problems during work. Roost and colleagues employed calibrated force-sensitive matting (Pliance system) to measure real-time pressure magnitudes and distribution in six horses ridden by four riders of equivalent ability but substantially different sizes, who each performed a standardised 30-minute dressage test; all thirteen tests involving heavy or very heavy riders were abandoned due to lameness or behavioural deterioration, compared with only one of twelve moderate-weight rider tests. Very heavy riders exhibited characteristic postural faults—seat extending beyond the saddle's cantle at walk, heels positioned cranial to the tubera coxae at trot and canter—alongside significantly elevated pressure concentrations at the caudal aspect of the saddle at walk and abnormally distributed pressure at faster gaits, with the highest peak pressures recorded during canter work. These findings suggest that rider-to-horse bodyweight ratios exceeding the 15–20% threshold create pressure patterns incompatible with musculoskeletal comfort, likely exacerbated by saddle fit issues and postural misalignment, indicating that professionals should regard such ratios as a biomechanical red flag warranting either rider reallocation or saddle and training intervention before lameness develops.
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Practical Takeaways
- •Riders exceeding ~15% of their horse's bodyweight are at high risk of causing lameness and behavioral problems—this should be a firm limit in practice, not a guideline.
- •Even moderate overweight riders (12-15% ratio) can cause issues; assess saddle fit specifically for each rider as ill-fitting saddles compound pressure problems and postural faults.
- •Heavy riders generate abnormally high peak pressures caudally and in canter; monitor these horses closely for early signs of back pain and musculoskeletal injury, and consider therapeutic intervention sooner than usual.
Key Findings
- •All 13 tests with heavy (H) and very heavy (VH) riders were abandoned due to lameness (n=12) or behavioral issues (n=1), versus only 1 of 12 moderate (M) rider tests abandoned.
- •Very heavy riders showed significantly higher caudal saddle pressures at walk (P<0.05) and highest maximum peak pressures in canter compared to lighter riders.
- •Very heavy riders had consistent postural faults including seat extending beyond saddle cantle and heels cranial to tubera coxae at trot and canter.
- •Pressure distribution patterns differed by rider weight: cranial dominance for light/moderate riders at rising trot, but similar cranial/caudal distribution for very heavy riders.