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

Russell Mackechnie-Guire,Diana Fisher,Vanessa Fairfax,Thilo Pfau,Mark Fisher,Erik Mackechnie-Guire

doi:10.3390/ani9100842

Russell Mackechnie-Guire, Diana Fisher + Show 4 more

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https://doi.org/10.3390/ani9100842

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Abstract

This study evaluated the effect of saddle tree width on thoracolumbar and limb kinematics, saddle pressure distribution, and thoracolumbar epaxial musculature dimensions. Correctly fitted saddles were fitted by a Society of Master Saddler Qualified Saddle Fitter in fourteen sports horses (mean ± SD age 12 ± 8.77 years, height 1.65 ± 0.94 m), and were altered to one width fitting wider and narrower. Horses were equipped with skin markers, inertial measurement units, and a pressure mat beneath the saddle. Differences in saddle pressure distribution, as well as limb and thoracolumbosacral kinematics between saddle widths were investigated using a general linear model with Bonferroni adjusted alpha (p ≤ 0.05). Compared with the correct saddle width, in trot, in the wide saddle, an 8.5% increase in peak pressures was found in the cranial region of the saddle (p = 0.003), a 14% reduction in thoracolumbar dimensions at T13 (p = 0.02), and a 6% decrease in the T13 range of motion in the mediolateral direction (p = 0.02). In the narrow saddle, a 14% increase in peak pressures was found in the caudal region of the saddle (p = 0.01), an 8% decrease in the range of motion of T13 in the mediolateral direction (p = 0.004), and a 6% decrease in the vertical direction (p = 0.004) of T13. Compared with the correct saddle width, in canter, in the wide saddle, axial rotation decreased by 1% at T5 (p = 0.03) with an 5% increase at T13 (p = 0.04) and a 5% increase at L3 (p = 0.03). Peak pressures increased by 4% (p = 0.002) in the cranial region of the wide saddle. Altering the saddle fit had an effect on thoracolumbar kinematics and saddle pressure distribution; hence, correct saddle fit is essential to provide unhindered locomotion.

Highlights

Correct saddle fit should enhance the athletic performance [1] of both the horse and rider.Incorrect saddle fit is thought to be a contributory factor towards equine thoracolumbar dysfunction, poor attitude to work, and poor performance [1,2,3,4,5,6,7] in the horse
One horse was excluded because his thoracolumbar dimensions were too narrow, resulting in a narrow saddle not being able to be fitted
This study has investigated the effect of tree width on thoracolumbar kinematics, limb kinematics, saddle pressure distribution, and thoracolumbar dimensions

Summary

Introduction

Correct saddle fit should enhance the athletic performance [1] of both the horse and rider.Incorrect saddle fit is thought to be a contributory factor towards equine thoracolumbar dysfunction, poor attitude to work, and poor performance [1,2,3,4,5,6,7] in the horse. A static saddle fitting assessment is performed featuring several criteria, as described elsewhere [14]. Once each criterion is met, a dynamic ridden assessment is performed, requiring the saddle fitter to observe the horse and rider in all gaits and in both directions. Industry guidelines (Society of Master Saddlers) state that the angle of the tree points should correspond to the angle of the horse’s back 5 cm from the caudal edge of the scapula in the static horse. Some saddle fitters (and others), despite industry guidelines, prefer to fit a saddle wider on the assumption that this will allow increased movement of the scapula and of the thoracic spine, both of which are not supported by any scientific evidence

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