Saddle Research Trust - Applying SCIENCE to SADDLES

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The Asynchrony Theory

The three-element asynchrony of horse, saddle and rider interaction After carrying out a series of innovative scientific studies throughout 2010, The Saddle Research Trust has discovered evidence that indicates measurable characteristics in saddle performance. This ground breaking new work has also highlighted previously unrecognised areas of saddle performance. These findings, which have the potential to be of great importance to the future of equine performance and welfare, urgently require further investigation. Out of these studies, a new theory has been born: The three-element asynchrony of horse, saddle and rider interaction.

Rider Asymmetry Initially, the object of the SRT studies was to measure the effect of rider asymmetry. However, it soon became apparent that there was a more complex pattern of interaction than could be simply explained by a rider sitting crookedly. Most people will be aware that their bodies are not perfectly symmetrical, and as riders, we are usually aware of being right or left-handed. In most instances, this “handing” tends to favour the right; even if a person writes with their left hand, their posture is generally right handed. This is commonly described by riding instructors as “collapsing the hip”. More accurately, this is described as “hyperflexion of the spine”. The rider will favour sitting more to the left of the saddle and in doing so, bend the waist to the right, and rotate the upper body to the right (Fig. 1). The effect of this is reduces coordination and balance, resulting in increased loading of the left stirrup and corresponding gripping with the right leg. Fig. 1 (right) - collapsing the right hip

The De-Coupling Effect In general terms, this means that the rider has a tendency to a vertical misalignment in the left/right plane: imagine a puppet on a string – if the strings on one side are loose, he will extend his joints, while the tighter strings on the opposite side will contract the joints – we describe this as decoupling. The decoupling effect describes the exaggerated loss of symmetry of the rider in the vertical plane. The movement of the horse’s back and limbs moves the saddle; the more rigid the frame of the saddle, the more movement will be generated. Our observation is that saddle movement is always asymmetrical. This generates an unstable platform for the rider. This instability consequently creates imbalance in the rider; the resulting compensatory action of the rider in turn accentuates asymmetrical posture. Fig. 1b (right) - the decoupling effect
In figs. 2a and 2b, the three-element asynchrony is clearly demonstrated. The same horse and rider are viewed in two different saddles. On the left, the rider can be seen in her own rigid saddle and on the right, in a flexible saddle. Taken during the same stride phase, the left hand image shows that when the right hind is weight bearing, the horse’s pelvis rolls to the left and the saddle drops to the right - the rider hyperflexes / decouples to the right. In the right hand image, the synchrony shows a marked improvement with the use of a flexible saddle Figs. 2a & 2b (below) The de-coupling effect: vertical misalignment


Horse Asymmetry A similar lack of symmetry exists in the horse in the horizontal plane. Like humans, horses tend to be right handed. The horse, by contracting the right side of his body, preferring to flex the neck and poll to the right, and therefore pushing more weight onto the left forelimb, often demonstrates this. The horse’s movement is no longer smooth and along two tracks. The horse “positions” itself to the right and moves the quarters crookedly. In trot, this can be observed as a tendency to swing the quarters to the left, but in the canter, this is reversed with the quarters usually swinging to the right. In conventional treed saddles, horses will tend to move the tree points alternately as the scapulae move back and forth against them. Any asymmetry either in scapular movement or shape will create greater asymmetrical movement of the saddle. Similarly, if the saddle is asymmetrical, it may create greater lateral excursions on one side of the horse’s back in comparison with the other. Fig. 3 (below) - The scapula swings against the tree point

This effect can be observed from the rear - the cantle swings from side to side as the horse moves along a straight line. In the example below, a wide shouldered native pony constantly pushes the saddle from right to left as he moves, creating an unstable platform for the rider. Figs. 4a & 4b (below) - Saddle movement creates an unstable platform for the rider

This effect can be exaggerated when the horse turns. The inner scapula will become more dominant in pushing against the tree point. Without the rider, the saddle may be even less stable at the rear with the subsequent swing even greater (Fig. 5). The weight of the rider will not stop the swing, but will serve to increase the torque against the horse’s back. Fig. 5 (below left) - The dominant scapula pushes against the tree point in the turn

In fig.6 (above right), the saddle has swung to the extreme right, positioning the left side of the base panel onto the extreme right side of the horse’s back.
In the past, riders have often been criticised for poor technique, and at times it may be true, but is far from the whole story, which is far more complex. In our studies it does not appear to be a simple “chicken and egg” that is “Which became crooked first - the rider or the horse?” It is better described as the “de-railing effect”.

The De-Railing Effect Imagine railway carriages running along on a track – if there is an obstruction that stops any part of the carriage from flowing freely along the track, it will de-rail. Fig. 6b (right) - The de-railing effect
The de-railing effect describes the loss of symmetry of the horse in the horizontal plane. This means in general terms that the horse has a tendency to horizontal or longitudinal misalignment. If the force generated by the hindlimbs is impeded, it will tend to push the vertebral column and limbs off track in a similar way to a train crash causing the carriages to de-rail and jacknife.
The horse compensates for carrying the asymmetrical rider and the subsequent loss of balance by counterbalancing with the neck and bracing against the load with the left forelimb. For example, this is often described by the rider as a tendency for the horse to “fall in” on the left rein. The hindlimbs are in turn prevented from swinging freely in a forward motion, no longer being able to travel in the same path as the blocked forehand therefore deviating to the side (Fig. 6b). The tendency is that the asymmetrical rider exagerrates the asymmmetry of the horse and vice versa. Our understanding is that the degree to which this exaggeration occurs is greatly affected by saddle design and fit. A saddle that can accommodate the correct movement of the horse without excessive movement or force will enable the horse and rider to be more symmetrical and balanced. The saddle can create a viscious circle or possibly a benign one.
A horse’s shape and movement can tilt the saddle either to the left or to the right whether it is static or in motion. The horse’s back shape is often asymmetrical, so even at halt, the saddle may settle crookedly on the horse’s back. Equally, the saddle may appear to sit symmetrically at halt, but moves asymmetrically when the horse moves. The pattern of this movement will also alter between different riders using the same saddle on the same horse.
Fig. 7 (above) - An asymmetrical back		Fig. 8 (above) - The saddle tilts to the left at halt
If there are any clinical reasons why the horse may favour one side of its body more than another, it may contract the musculature on one side and move in an unlevel fashion, even if not overtly lame, causing the saddle to be carried asymmetrically. Many low-grade hind limb lamenesses are not readily apparent, even to highly specialised equine veterinary clinicians and in some cases, the only clue may be that the horse does not carry the saddle symmetrically. So-called “bridle lameness” is often a ridden performance issue that cannot be simply explained, but may be a complex cocktail of symptoms involving subtle asymmetries in the horse and its movement, the rider, the saddle and most importantly, the interaction between them. In fig.8 (above right), the saddle can be seen tilting to the left at halt, thus leaving the rider’s left seatbone unsupported and causing her pelvis to drop to the left.
The same combination, in sitting trot, generates a more complex pattern:
	When the left hindlimb is weight bearing, the horse’s pelvis rolls to the right and the saddle moves and tilts to the left, taking the rider’s pelvis with it (left). Fig.9a (left) - Left hind weight bearing
	When the right hind is weight bearing, the saddle and rider are aligned. This is an asymmetrical pattern, demonstrating a clear lack of synchronisation in the three-way interaction of horse, saddle and rider (right). Fig. 9b (right) - Right hind weight bearing

In most research studies, if a single question is asked, the answer is often a myriad more questions. We have raised such questions as: “What effect does this three-way asynchrony in the interaction of horse, saddle and rider have on the welfare and performance, not just of the horse, but also of the rider?” Furthermore “ Do different saddle designs affect the synchrony in different ways?” This valuable work may be in its infancy, but will have far-reaching effects. This valuable work may be in its infancy but will have far-reaching effects, having demonstrated a clear need for further investigation into the levels of asymmetry found and the potential to utilise this in the diagnosis of clinical lameness. The fast pace of technological development means that we are now able to utilise systems that can analyse performance parameters and investigate the effect of concepts that can make a real impact at all levels of equestrianism, from amateur to elite.

The Saddle Research Trust is continuing its work in investigating welfare and performance in the horse and rider and will publish the results of current studies as they become available.
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