Range of motion and between-measurement variation of spinal kinematics in sound horses at trot on the straight line and on the lunge

Abstract

Clinical assessment of spinal motion in horses is part of many routine clinical exams but remains highly subjective. A prerequisite for the quantification of spinal motion is the assessment of the expected normal range of motion and variability of back kinematics. The aim of this study was to objectively quantify spinal kinematics and between-measurement,-surface and-day variation in owner-sound horses. In an observational study, twelve ownersound horses were trotted 12 times on four different paths (hard/soft straight line, soft lunge left and right). Measurements were divided over three days, with five repetitions on day one and two, and two repetitions on day three (recheck) which occurred 28-55 days later. Optical motion capture was used to collect kinematic data. Elements of the outcome were: 1) Ranges of Motion (ROM) with confidence intervals per path and surface, 2) a variability model to calculate between-measurement variation and test the effect of time, surface and path, 3) intraclass correlation coefficients (ICC) to determine repeatability. ROM was lowest on the hard straight line. Cervical lateral bending was doubled on the left compared to the right lunge. Mean variation for the flexion-extension and lateral bending of the whole back were 0.8 and 1 degrees. Pelvic motion showed a variation of 1.0 (pitch), 0.7 (yaw) and 1.3 (roll) degrees. For these five parameters, a tendency for more variation on the hard surface and reduced variation with increased repetitions was observed. More variation was seen on the recheck (p<0.001). ICC values for pelvic rotations were between 0.76 and 0.93, for the whole back flexion-extension and lateral bending between 0.51 and 0.91. Between-horse variation was substantially higher than within-horse variation. In conclusion, ROM and variation in spinal biomechanics are horse-specific and small, necessitating individual analysis and making subjective and objective clinical assessment of spinal kinematics challenging.

Rater agreement for assessment of equine back mobility at walk and trot compared to quantitative gait analysis

“…However, the large scale on which pathology was suspected and the huge variety of scores per individual horse make this theory unlikely. Another reason why this explanation is unlikely is that Hardeman et al [ 10 ], when measuring range of motion and between measurement variation of spinal kinematics in 12 owner-sound horses in trot, found lower rather than higher ROM (Range Of Motion) for pelvis roll, pitch and yaw and for whole back flexion-extension and whole back lateral bending compared to the current study ( S6 Table ).…”

“…All kinematic data was filtered, and analysed as previously described [ 10 ]. Segment angles (T12, T15, T18, L3, L5, S5 , TS) were calculated using the markers cranial and caudal to the marked vertebra in question.…”

“…Pelvic roll (axial rotation), pitch (FE) and yaw (LB) were calculated as projection angles in the frontal, sagittal and dorsal planes, respectively using the markers at TS and both tuber coxae. The back data was processed by previously described methods using Matlab 2019b b [ 10 ].…”

“… Comparison of pelvis roll, pitch, yaw and whole back flexion- extension and whole back lateral bending on hard straight surface in trot between horses in current study with those in Hardemans study [ 10 ]. …”

Adaptations in equine axial movement and muscle activity occur during induced fore‐ and hindlimb lameness: A kinematic and electromyographic evaluation during in‐hand trot

“…Quantitative equine gait analysis has been applied to measure axial motion in nonlame horses 6–9 and to quantify adaptive changes in axial motion in horses with induced lameness or back pain 10–13 during treadmill locomotion. Increased thoracolumbar range of motion (ROM) was observed in horses with induced unilateral back pain 12 and FL lameness, 10 but not during induced unilateral HL lameness 11 .…”