Head, withers and pelvic movement asymmetry and their relative timing in trot in racing Thoroughbreds in training.
Authors: Pfau T, Noordwijk K, Sepulveda Caviedes M F, Persson-Sjodin E, Barstow A, Forbes B, Rhodin M
Journal: Equine veterinary journal
Summary
# Editorial Summary: Head, Withers and Pelvic Movement Asymmetry in Trotting Thoroughbreds Gait asymmetries in racing Thoroughbreds are typically assessed through head and pelvic movement patterns, yet the role of withers motion in this compensation mechanism remains poorly understood. Researchers analysed inertial sensor data from 163 Thoroughbreds during trot-ups on hard ground, quantifying movement asymmetry and the timing of displacement peaks and troughs across the head, withers and pelvis, then stratifying horses by the directional relationship (same-sided or opposite-sided) between head and withers asymmetry. The direction of head versus withers asymmetry predicted the relationship between head and pelvic asymmetry in 69–77% of horses, with pelvic movement patterns differing significantly between those with same-sign versus opposite-sign head-withers asymmetry (P<0.0001); notably, horses displaying opposite-sided head and withers asymmetry showed delayed upward head movement following contralateral ('sound') forelimb stance compared to withers and pelvis timing (P=0.02 and P=0.04 respectively). For practitioners, these findings suggest that withers asymmetry warrants greater clinical attention as a potential discriminator between forelimb and hindlimb lameness sources, and that the head-withers relationship may offer a more nuanced interpretation of compensatory movement patterns than head and pelvic data alone—particularly in identifying the timing of motion anomalies that distinguish different underlying biomechanical causes.
Read the full abstract on PubMed
Practical Takeaways
- •Assessment of both head and withers movement patterns together provides better prediction of hindlimb versus forelimb lameness than head movement alone in Thoroughbreds
- •The timing and direction relationship between head and withers displacement can help clinicians identify whether a gait asymmetry involves ipsilateral or contralateral limb compensation
- •Inertial sensor technology enables objective measurement of these subtle movement patterns for more accurate lameness localization during clinical trot-ups
Key Findings
- •Head-withers asymmetry relationship predicts head-pelvic asymmetry patterns in 69-77% of horses with natural gait asymmetries
- •Pelvic movement asymmetry is significantly different between horses with same-sided versus opposite-sided head-withers asymmetry (P<0.0001)
- •Horses with opposite-sided head-withers asymmetry show delayed timing of maximum head height after contralateral stance compared to withers and pelvis (P=0.02-0.04)
- •Withers movement patterns may help differentiate between forelimb and hindlimb lameness in naturally occurring gait asymmetries