Differential rotational movement and symmetry values of the thoracolumbosacral region in high-level dressage horses when trotting

Abstract

High-level dressage horses regularly perform advanced movements, requiring coordination and force transmission between front and hind limbs across the thoracolumbosacral region. This study aimed at quantifying kinematic differences in dressage horses when ridden in sitting trot–i.e. with additional load applied in the thoracolumbar region–compared with trotting in-hand. Inertial sensors were glued on to the midline of the thoracic (T) and lumbar (L) spine at T5, T13, T18, L3 and middle of the left and right tubera sacrale of ten elite dressage horses (Mean±SD), age 11±1 years, height 1.70±0.10m and body mass 600±24kg; first trotted in-hand, then ridden in sitting trot on an arena surface by four Grand Prix dressage riders. Straight-line motion cycles were analysed using a general linear model (random factor: horse; fixed factor: exercise condition; covariate: stride time, Bonferroni post hoc correction: P<0.05). Differential roll, pitch and yaw angles between adjacent sensors were calculated. In sitting trot, compared to trotting in-hand, there was increased pitch (mean±S.D), (in-hand, 3.9 (0.5°, sitting trot 6.3 (0.3°, P = <0.0001), roll (in-hand, 7.7 (1.1°, sitting trot 11.6 (0.9°, P = 0.003) and heading values (in-hand, 4.2 (0.8), sitting trot 9.5 (0.6°, P = <0.0001) in the caudal thoracic and lumbar region (T18-L3) and a decrease in heading values (in-hand, 7.1 (0.5°, sitting trot 5.2 (0.3°, P = 0.01) in the cranial thoracic region (T5-T13). Kinematics of the caudal thoracic and lumbar spine are influenced by the rider when in sitting trot, whilst lateral bending is reduced in the cranial thoracic region. This biomechanical difference with the addition of a rider, emphasises the importance of observing horses during ridden exercise, when assessing them as part of a loss of performance assessment.

The Effect of Chiropractic Treatment on Limb Lameness and Concurrent Axial Skeleton Pain and Dysfunction in Horses

“…Most inertial sensor-based studies focus on capturing measures of limb lameness with little to no regard for the potential confounding effects of axial skeleton pain or dysfunction [ 55 , 56 ]. Typical inertial sensor placement is on the dorsum of the head and pelvis [ 35 ]; therefore, it is expected that altered head and pelvic displacement due to axial skeleton pain or stiffness would directly affect measures of limb lameness [ 57 , 58 ]. The large variability in the reported vector sum values for the forelimbs supports this.…”

Saddle Thigh Block Design Can Influence Rider and Horse Biomechanics

“…These were used as part of a sensor-based system (Xsens MTw Awinda), which has been validated for translational displacements derived from internal tri-axial sensor accelerations, which were then rotated into a horse-based reference frame based on the sensor orientation estimate and then double integrated into the displacement [ 16 , 18 ]. Data processing methods have been described elsewhere [ 19 , 20 ]. In brief, orientation-time signals for differential axial rotation, flexion-extension, and lateral bending values of T5, T13, L3, and TS were used to calculate differential rotational movement, as described by MacKechnie-Guire and Pfau 2021a, 2021b [ 2 , 19 ].…”

Inertial Sensor Technologies—Their Role in Equine Gait Analysis, a Review

“…Other studies that have used the Xsens ® technology to study the biomechanics of the equine pelvic, thoracic, and lumbar regions have demonstrated that the saddle and the rider have a significant effect on the kinematics of the equine spine. MacKechnie-Guire et al [ 85 ] reported changes in the thoracolumbosacral region of dressage horses when ridden in sitting trot as compared to trotting in hand. Increased range of motion (ROM) was found in the caudal thoracic and lumbar regions (T18-L3) in sitting trot.…”

“…Increased range of motion (ROM) was found in the caudal thoracic and lumbar regions (T18-L3) in sitting trot. Cranial thoracic motions remained unchanged, but heading rotational values declined [ 85 ]. In another study, the ROM of the caudal thoracic and thoracolumbar regions decreased by −1.3 (0.4)° and −0.6 (0.2)°, respectively, while protraction and retraction angles increased during rising trot as compared to trotting in hand.…”