Reducing peak pressures under the saddle at thoracic vertebrae 10-13 is associated with alteration in jump kinematics

Abstract

There is little information about horse-saddle interaction at take-off for a fence, although there is potential that this could have an influence on performance. It was hypothesised that (1) maximum peak pressure under the saddle would occur in the phase of maximum thoracolumbar flexion prior to hindlimb take-off; and (2) limb and trunk kinematics at take-off over the fence would be affected by reducing peak pressure at Thoracic vertebrae (T)10-13 at the point in the stride where peak pressures occur. The peak pressures under the usual saddle (Saddle S) and a saddle modified to reduce peak pressures at T10-13 (Saddle F) were measured during approach and take-off over a 1.30 m upright fence in 12 elite jumping horses. The timing of peak pressures was determined by comparison with simultaneous video data. Shoulder, carpal flexion angle and trunk angle to the horizontal at hindlimb take-off, take-off distance from the fence and fetlock height above the fence were determined using high speed motion analysis. Peak pressures under the saddle at T10-13 and kinematic data were compared between Saddles S and F. Maximum peak pressures occurred at forelimb vertical, during hindlimb protraction, consistent with thoracolumbar ventroflexion. Saddle F was associated with significantly lower peak pressures at T10-13, greater shoulder and carpal flexion, a steeper trunk angle, and higher fetlock height above the fence than Saddle S. Forelimb take-off distance from the fence was not different between saddles, but hindlimbs were significantly closer to the fence with Saddle F, indicating potential increase in ventroflexion through the thoracolumbosacral region. These findings suggest that reducing peak pressures under the saddle at T10-13 are associated with altered kinematics during the approach and take-off over a fence, which may have a positive effect on jumping performance.

The Effect of Tree Width on Thoracolumbar and Limb Kinematics, Saddle Pressure Distribution, and Thoracolumbar Dimensions in Sports Horses in Trot and Canter

“…The cranial region of the thoracic spine (T10–T13) is of great interest; it is where the rider’s centre of mass aligns approximately above the horse’s centre of mass. It is the area where the saddle is at its narrowest and it is also a region that has been reported to be associated with muscle activity [36] and improved gait features when saddle pressure in this region was reduced after modified saddle design [15,26]. Increased amplitudes have been reported in the dorsoventral ROM occurring at T13 compared with T18 and L3 in non-lame horses trotting in a straight line [37].…”

“…Finally, further support that saddle width has an effect on the thoracolumbar spine arises from our thoracolumbar dimensions. The thoracolumbar musculature has been reported to change over a year as a result of changes in body weight, seasonal variations, and saddle fit [30], as well as after thirty minutes of exercise when horses are worked correctly in a well fitted saddle [29], and also after modifications of the saddle resulting in reduced saddle pressures in the thoracic region [15,26]. In the current study, smaller epaxial musculature dimensions were found at T13 after ridden exercise in the wide saddle.…”

“…Prior to the study, the pressure mat was calibrated, and during testing (for each horse), the pad was zeroed without the saddle, girth, or rider [23]. It was fitted so that the pressure mat was on top of the horse’s skin and beneath the saddle cloth and saddle, as previously described [15,24,25,26,27]. Peak pressures (kPa) and maximum force (N) (sum of all sensors x area) in trot and canter for all saddle conditions were collected.…”

“…Measurements of dorsal thoracolumbar body shape of each horse were obtained following the SMS guidelines [17]. The thoracolumbar dimensions (widths at 3 cm and 15 cm ventral to the dorsal midline) were measured at the level of the T10, T13, and T18 [15,26,29,30] prior to ridden exercise and immediately after data had been collected for each saddle (correct, narrow, and wide), and then drawn onto A3 graph paper and the width measured at 3 cm and 15 cm ventral to the dorsal midline. The coefficient of variance was p < 0.04 for all measurements using three repeats per measurement.…”

A Systematic Approach to Comparing Thermal Activity of the Thoracic Region and Saddle Pressure Distribution beneath the Saddle in a Group of Non-Lame Sports Horses

“…The saddle is an essential piece of equipment coupling the horse and rider. The effects of saddle fit [ 1 , 2 , 3 ] and saddle design [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ] on equine health and performance are becoming better understood. Incorrect saddle fit is thought to be a potential contributing factor in the context of back problems, poor attitude to work and poor performance [ 3 , 12 , 13 , 14 , 15 , 16 , 17 ].…”