Although we know that horses move differently on a circle to how they move in a straight line, the differences in movement of the back haven’t been measured. This study set out to address that. The authors found that there was less symmetry in the movement of the back within the stride on a circle compared to on a straight line. There was more flexion and extension of the back on the circle compared to the straight, and more side bending. They also noted that moving on a circle created a movement pattern similar to an inside hind lameness. The study concluded that there are measurable differences in the movement of the horses back on a circle compared to on a straight line, and that this is linked with changes in the movement of the hindlimbs.
Greve L, Pfau T, Dyson S. Thoracolumbar movement in sound horses trotting in straight lines in hand and on the lunge and the relationship with hind limb symmetry or asymmetry. Vet J. 2017 Feb;220:95-104. doi: 10.1016/j.tvjl.2017.01.003. Epub 2017 Jan 4. PMID: 28190505
You can access the full article here.
Equine movement symmetry is changed when turning, which may induce alterations in thoracolumbosacral kinematics; however, this has not previously been investigated. Our objectives were to document thoracolumbar movement in subjectively sound horses comparing straight lines with circles on both reins and to relate these observations to the objectively determined symmetry/asymmetry of hindlimb gait. Fourteen non-lame horses were assessed prospectively in a non-random, cross-sectional survey. The horses were trotted in straight lines and lunged on both reins and inertial sensor data collected at landmarks: withers, T13 and T18, L3, tubera sacrale, and left and right tubera coxae. Data were processed using published methods; angular motion range of motion (ROM; flexion-extension, axial rotation, lateral bending) and translational ROM (dorsoventral and lateral) and symmetry within each stride were assessed. The dorsoventral movement of the back exhibited a sinusoidal pattern with two oscillations per stride. Circles induced greater asymmetry in dorsoventral movement within each stride (mean ± standard deviation, up to 9 ± 6%) compared with straight lines (up to 6 ± 6%). The greatest amplitude of dorsoventral movement (119 ± 14 mm in straight lines vs. 126 ± 20 mm in circles) occurred at T13. Circles induced greater flexion-extension ROM (>1.3°; P = 0.002), lateral bending (>16°; P <0.001), and lateral motion (>16 mm; P = 0.002) compared with straight lines. Circles induced a movement pattern similar to an inside hindlimb lameness, which was significantly associated with the circle-induced greater asymmetry of dorsoventral movement of the thoracolumbar region (P = 0.03). Moving in a circle induces measurable changes in thoracolumbar movement compared with moving in straight lines, associated with alterations in the hindlimb gait.
Dr Sue Dyson and I are in the process of writing a book for horse owners and riders on how to understand and use the Ridden Horse Pain Ethogram with your own horse. The book will be published by J A Allen, and available sometime In 2023. Sign up to my newsletter at www.thehorsephysio.co.uk for updates.
In the meantime, you can learn more about the Ridden Horse Pain Ethogram through listening to Dr Sue Dyson explaining here it on the Equine Veterinary Education, where you can also listen to her discussing many of the other studies that she has been involved in. You can also take an online course with Equitopia.
© Sue Palmer, The Horse Physio 2021
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