The effect of foot imbalance on point of force application in the horse.
Authors: Wilson, Seelig, Shield, Silverman
Journal: Equine veterinary journal
Summary
# Editorial Summary: The effect of foot imbalance on point of force application in the horse Foot imbalance represents a suspected major risk factor for musculoskeletal injury in horses, yet the precise biomechanical mechanisms remain poorly characterised. Wilson and colleagues used forceplate analysis during trotting to examine how wedges of 3.7 and 5 degrees applied to the forefeet of eight Thoroughbred-type horses altered the distribution of loading across the sole. The critical finding was that mediolateral imbalance displaced the centre of pressure by approximately 10 mm towards the elevated side throughout the entire stance phase, with heel elevation delaying unloading and toe elevation advancing it; notably, horses showed no compensatory load redistribution even 24 hours post-shoeing. This inability to adapt acutely to foot imbalance indicates that concentrated loading persists in the elevated region, potentially leading to secondary structural damage and altered horn growth patterns in that quadrant. For practitioners, these results underscore the biomechanical necessity of precise mediolateral balance in shoeing and trimming, suggesting that even modest imbalances create sustained mechanical stress that warrants careful assessment and correction rather than reliance on the horse's adaptive capacity.
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Practical Takeaways
- •Foot imbalance creates measurable, sustained shifts in loading patterns that the horse cannot self-correct—even small wedge angles (3.7–5°) matter
- •Higher loads concentrate in the elevated region of an imbalanced foot, potentially damaging hoof structure and horn growth over time; early detection and correction are critical
- •Shoeing changes should be assessed carefully, as the horse's loading pattern stabilises within 24 hours, making longer-term monitoring essential to evaluate therapeutic benefit
Key Findings
- •Standard steel horseshoes on balanced feet have minimal effect on force application trace during stance
- •Mediolateral hoof imbalance causes approximately 10 mm displacement of force application in the direction of the wedge throughout stance
- •Heel elevation delays heel unloading while toe elevation advances toe unloading
- •Horses cannot acutely compensate for foot imbalance by redistributing load under the foot, leading to higher loads in elevated regions