The design of the thigh block on saddles can influence rider and horse biomechanics, researchers have found.
Rossdales’ sport horse specialist Rachel Murray and her fellow researchers, writing in the journal Animals, said there is increasing interest in the effect of saddle design on horse kinematics. There is, however, little evidence on the influence on rider-saddle interaction and how this affects horse movement patterns.
The study team set out to investigate the effect of changing the design of the saddle’s thigh block on the interaction between the rider and saddle, as well as the effect it had on both rider and horse movement.
They noted that knee blocks are traditionally non-deformable, with the purpose of supporting the rider’s knee, as the knee is resisted from travelling forwards during locomotion.
Over the past decade, knee block size has increased, evolving to support the thigh and being referred to as thigh blocks. Various thigh block designs are available in terms of shape, size, height, and position. They tend to be made from a hand-rasped block of a semi-rigid material.
Some riders prefer a larger thigh block, as it will provide additional support whilst riding, whereas others may feel that a larger thigh block is restrictive.
The researchers noted that although thigh blocks are a prominent feature on saddles, little is known about their effect on the rider and, consequently, the horse.
“Therefore, it is possible that restriction of rider movement by a thigh block during the stride cycle might alter the rider’s movement patterns, the effectiveness of the seat, and their ability to move synchronously with the horse, which, in turn, has the potential to affect equine locomotion,” the study team said.
Their study centered on two different thigh block designs positioned similarly on a standardised saddle. One was a conventional vertical-faced solid block, while the other block had a multi-layered deformable face, which made it less restrictive.
The researchers hypothesised that the contact area and the magnitude of pressures between the rider’s seat and saddle, rider trunk and leg kinematics, and horse thoracolumbar and limb kinematics, would differ between the two designs.
In their study, they placed a seat pressure mat between the rider and saddle, which was used to assess the contact area, average and peak pressure between the rider and saddle. Tracking technology was employed to analyse horse and rider movement.
The study centred on 18 elite sport horses, comprising 12 dressage horses and six eventing horses.
Two male and two female FEI Grand Prix dressage riders were recruited, as well as one male and one female FEI-ranked five-star eventing rider.
All horses were trotted in well-fitting dressage saddles that were identical, except for the thigh block design.
The results from straight-line locomotion when in sitting trot showed that the thigh block with the more deformable face resulted in a greater contact area and more pressure between the rider’s seat and the saddle, as well as a more upright rider position when the horse’s limbs were on the ground.
The study team also identified an association between thigh block design, horse spinal movement, and forelimb flexion.
The overall effect was a more consistent rider-saddle interface and a more upright rider trunk during stance when the block with the more deformable face was used. There was also an increase in horse thoracic stability and lumbar lateral bend, and improved forelimb flexion.
The findings, they said, support the importance of optimising rider-saddle-horse interaction.
A longer study would be advantageous to determine if the differences identified were sustained or altered over time, they said.
“This study only quantified horse and rider kinematics when trotting,” they noted. “Future studies should quantify the effect that a saddle thigh block has on the rider-saddle-horse interaction when in walk and canter, when riding in different riding positions, and when used by less skilled or symmetrical riders.”
The study team comprised Rachel Murray (Rossdales Veterinary Surgeons), Mark Fisher (Woolcroft Saddlery), Vanessa Fairfax (Fairfax Saddles) and Russell MacKechnie-Guire (Centaur Biomechanics) and the Department of Clinical Science and Services at the Royal Veterinary College.
Murray, R, Fisher, M, Fairfax, V, MacKechnie-Guire, R. Saddle Thigh Block Design Can Influence Rider and Horse Biomechanics. Animals 2023, 13, 2127.://doi.org/10.3390/ani13132127