Horizontal moment around the hoof centre of pressure during walking on right and left circles.
Authors: Heaps L A, Franklin S H, Colborne G R
Journal: Equine veterinary journal
Summary
Horses walking on circles experience asymmetrical twisting forces through their front hooves that differ from the symmetrical pattern observed in straight-line movement, according to this biomechanical analysis of six Thoroughbreds led across a force platform on 5-metre radius circles. Using force plate data to calculate horizontal moments around each hoof's centre of pressure, researchers found that on a left circle, most horses generated internal (medially directed) twisting moments under both front hooves, whilst on a right circle the pattern shifted to internal moments on the left forehoof but weak external (laterally directed) moments on the right—a directionally dependent response not seen in the hind limbs, which remained bilaterally consistent. Individual horses showed low variability in their own moment patterns across multiple trials, yet substantial variation existed between horses, particularly in forelimb mechanics, suggesting that asymmetrical loading is a genuine biomechanical feature rather than measurement error. For practitioners—particularly those designing rehabilitation programmes for distal limb injuries—this finding has important implications: circular exercise creates directionally dependent stress patterns in the forehooves that warrant careful consideration when prescribing work on circles, and bilateral assessment of movement mechanics should be standard practice rather than evaluating limbs independently. Future research examining joint motion in the distal limb during circular work should account for these horizontal moment variations to avoid missing clinically relevant loading asymmetries.
Read the full abstract on PubMed
Practical Takeaways
- •Circle work produces asymmetric loading in forelimbs that varies between individual horses; rehabilitation programmes for distal limb injuries should account for this asymmetry during exercise prescription.
- •Bilateral assessment of distal limb joint motion is essential when evaluating horses, as moment patterns differ between left and right limbs during curved pathwork.
- •The consistency of hind limb moments suggests forelimbs are the primary concern when addressing rotational mechanics during circle work in rehabilitation.
Key Findings
- •Five of 6 horses exerted internal moments around the left forehoof on left circles, while on right circles 5 of 6 exerted internal moments around the left forehoof with weak external moments on the right.
- •Hind hoof moments were bilaterally similar between right and left circles, showing symmetry unlike forelimbs.
- •Intrahorse variability in applied moments is low, but interhorse variability is notable especially in forelimb moments, indicating mechanical asymmetry between individuals.
- •Horizontal twisting moments around the hoof centre of pressure vary between forelimbs in some horses during circle work at walk.