Unilateral-Dominant Lameness Induces Changes in Breakover Duration Symmetry in Equine Walk
Authors: Briggs Eloïse Virginia, Mazzà Claudia
Journal: International Journal of Equine Science
Summary
# Editorial Summary: Breakover Duration as a Lameness Indicator Whilst equine professionals have long understood how lame horses shift weight to spare an affected limb, the mechanical behaviour of the distal structures during the critical breakover phase—when the hoof experiences peak tensile loading—has received little attention. Briggs and Mazzà used hoof-mounted gyroscopes to measure breakover duration across 16 horses (5 sound, 11 lame as identified by owners) during walk, hypothesising that lameness would disrupt the natural symmetry between contralateral limb pairs. Sound horses demonstrated high symmetry with mean breakover durations of 168ms per limb (absolute difference of only 6ms between pairs), whilst lame horses showed marked asymmetry: affected limbs prolonged breakover to 167ms compared with their contralateral partners at 146ms—a clinically significant 21ms difference (p < 0.001). Notably, ipsilateral and diagonal limbs maintained comparable durations to sound limbs, suggesting the compensation is localised rather than global. These findings propose breakover duration asymmetry as a quantifiable marker for detecting lameness, particularly valuable for farriers and physiotherapists seeking objective gait analysis metrics beyond visual assessment; practitioners should consider whether extended breakover in one limb of a pair might indicate pain or mechanical dysfunction in that limb, warranting further investigation.
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Practical Takeaways
- •Lameness detection at walk can be objectively measured using breakover duration symmetry via hoof-mounted gyroscopes—the lame limb shows significantly prolonged breakover compared to its pair
- •Horses compensate for lameness through ipsilateral and diagonal limb adjustments while maintaining symmetry in non-affected contralateral pairs, suggesting a specific biomechanical strategy
- •Breakover duration asymmetry between contralateral limbs could become a useful diagnostic tool for detecting subtle lameness where traditional visual assessment may be inconclusive
Key Findings
- •Sound horses showed high symmetry in breakover duration between contralateral limbs (mean 168ms, absolute difference 6ms, p=0.07)
- •Lame horses exhibited significantly longer breakover duration in affected limbs (167ms) versus contralateral limbs (146ms, p<0.001)
- •Ipsilateral (160ms) and diagonal (162ms) limbs showed breakover durations comparable to sound horses, indicating compensation pattern
- •Breakover duration asymmetry may serve as a quantifiable marker for detecting lameness in equine gait analysis