Saddle and stirrup forces of equestrian riders in sitting trot, rising trot, and trot without stirrups on a riding simulator
Authors: T. Bye, Vicky Lewis
Journal: Comparative Exercise Physiology
Summary
Vertical forces transmitted through the saddle represent a significant welfare concern for horses, yet the mechanical role of stirrups in distributing rider weight has been poorly characterised. Bye and Lewis investigated this gap by measuring saddle and stirrup forces in fourteen amateur female riders across three trotting conditions—sitting trot with stirrups, rising trot, and sitting trot without stirrups—using a riding simulator with instrumented equipment to capture 20-second force recordings. Removing stirrups during sitting trot produced significantly higher peak vertical saddle forces (P=0.011) compared to riding with stirrups, demonstrating that stirrups actively attenuate the rider's vertical acceleration and reduce impact loading on the horse's back. The findings also revealed consistent rightward asymmetry across all conditions (P<0.001), suggesting habitual postural imbalances in these riders, alongside asymmetrical stirrup use (significantly higher left stirrup peak forces in sitting trot; P=0.039). For practitioners, these results indicate that while stirrup-free work may develop rider balance and core stability, the acute increase in dorsal loading warrants cautious integration into training programmes; more fundamentally, the persistent asymmetrical force patterns suggest that individual rider assessment and postural retraining could meaningfully improve both horse welfare and performance, though validation on live horses remains essential before clinical recommendations can be solidified.
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Practical Takeaways
- •Stirrups function as essential stabilizers that reduce vertical forces transmitted to the horse's back; riding without stirrups creates significantly higher peak forces that may increase injury risk
- •Rider asymmetry (higher right-side forces) is consistent and substantial; identify and address individual riders' asymmetrical positioning to reduce uneven loading on the horse's spine and musculature
- •Training methods involving riding without stirrups should be reconsidered until live horse studies confirm these simulator findings, as they appear to increase potentially damaging vertical forces
Key Findings
- •Peak vertical saddle forces were significantly higher in sitting trot without stirrups compared to with stirrups (P=0.011)
- •Right-side saddle forces were consistently higher than left-side forces across all three conditions (P<0.001)
- •Stirrups play an important role in controlling vertical acceleration of the rider relative to the horse
- •Left stirrup forces tended to be higher in both sitting and rising trot, with significant difference in peak force during sitting trot (P=0.039)