A well-fitted saddle should distribute pressure evenly to avoid any point of pressure on the horse's back and not restrict the movement of the horse. The saddle must fit both the rider and the horse, because poor saddle fit is associated with back pain in horses. This article is a summary of the findings of a study published in 2017 in the Journal of Equine Veterinary Science that looked at the effects of large saddle panels on the biomechanics of the equine back during rising trot.
Latest developments in saddle design:
A saddle is traditionally composed of a rigid tree made of wood and metal, around which the saddle is constructed. The aim of the saddle tree is to distribute the weight and inertial forces of the rider over the horse's back. However, it's rigidity can interfere with the change in the shape of the horses back that naturally occurs during movement. Several saddle makers have tried to solve this problem by employing new materials like composite to create flexible trees. The use of pressure mats has allowed testing of these improvements. An electronic pressure mat records pressure distribution under the saddle during locomotion at different gaits when the shape of the horse's back and the force exerted by the rider are continually changing. It has been shown that if a saddle is not fitted properly then the tree can create high focal pressure or a bridging pressure distribution where there is high pressure at the front and the back of the saddle with little support directly under the riders seat. In response, attempts have been made to develop treeless saddles that are more flexible so as to provide an adaptable interface between the horse and the rider. However, studies have demonstrated that treeless saddles are more likely to concentrate the pressure of the rider on a localized area of the horse's back i.e. underneath the rider's seat bones.
The saddle tree is not the only factor to take into account with regards to fitting the saddle to the horse. Panels, by their shape and materials, also have an important role to play in pressure distribution. An evaluation of different types of saddle pads showed that the choice of material has a major influence on pressure distribution. Although there is much variation in the properties of different foam, it has been shown that wool panels result in a better pressure distribution with smaller pressure values than foam panels.
Saddle Panels and Biomechanics of the Equine Back
The aim of this study was to better understand the effect of the size of saddle panels on the biomechanics of the horse's back. The study took a prototype saddle which had panels that were 5cm wider along the middle and rear section of the panels and compared it with a standard saddle. It was hypothesized that a saddle with larger panels may decrease load pressure by increasing the contact area but, because of this increased contact with the horse's back, may induce smaller movements of the spine. In this study, pressure distribution between the saddle and the horses back was measured using an electronic pressure mat. Additionally, sensors were placed along the horses spine to assess the range of motion of the thoracic and lumbar vertebrae. Stirrup force sensors and 2D motion capture cameras were also employed.
It was found that when the rider is in the sitting phase of the trot, the larger panels induced an increase in the contact area behind the riders seat and resulted in a more uniform distribution of pressure along the horse's back under the saddle. This more homogenous pressure distribution was associated with an increased range of motion of the back with greater flexion and extension of the spine under the seat of the rider. Interestingly, the range of motion of the horse's back became closer to the values observed in unridden horses.
This study demonstrated that saddle panel shape has an important role to play in the distribution of saddle/rider pressure on the horse's back. Furthermore, saddle panel shape influences the range of motion of the horse's back. Uniformity of pressure distribution under the saddle improves the movement of the horses back under the seat of the rider during the seated phase of the trot and is associated with an increased range of motion of flexion and extension of the horse's back.
Reference:
Martin P, Cheze L, Pourcelot P, Desquilbet L, Duray L, Chateau H. Effects of large saddle panels on the biomechanics of the equine back during rising trot: Preliminary results. J Equine Vet Sci 2017:48:15-22