How old-fashioned static saddle fitting differs from dynamic saddle fit for the moving horse.
Three different metal parts used in riding come in close contact with the horse. One is the bit, one is the horse’s shoes, and the last is the gullet plate of the saddle. Each of these needs to be fitted properly to your horse – two of them by trained experts who have an understanding of equine anatomy. But just like fitting a shoe, there are different opinions as to how gullet plates need to be fitted when it comes to saddle fitting.
The importance of proper gullet plate fit
The most verified long term damage to a horse’s back has been proven to result from incorrectly fitted gullet plates (the plate that fits across the head or pommel of the saddle). Fiber optic cameras, MRIs, thermography, laser sensors, 3D animation and computerized saddle pads have made it very clear that the A-Frame withers of the static horse becomes a U-Frame in motion. In Diagram A, this is illustrated by the broken green line representing the wither shape in motion. Therefore, symptomatic white hairs always show up at the top of the side of the withers, where the gullet plate generally pinches if it doesn’t fit. We have already discussed the necessity of matching both the angle and width of the gullet plate and tree points to the horse’s conformation at the withers and shoulder muscles.
Fitting the horse in motion
The gullet plate shape and size has to be set to accommodate the moving horse. Many saddle fitters can fit an English saddle to a horse that is standing still in the crossties. There are traditional points of reference for static fit – wither clearance, panels touching evenly all the way down, etc. Where it becomes interesting, and where it becomes difficult beyond the ability of many saddle fitters, not to mention the capability of the saddle construction itself, is fitting the saddle so that it works when the horse begins to move.
When saddle fitting, remember that the saddle sits on many different muscle groups on the horse’s back. To begin explaining the importance of gullet plate fit, we start at the front of the saddle under the pommel, where the metal gullet plate is. The gullet plate needs to align with the angle and width of the shoulder. The shoulder moves upwards and backwards 4” to 8” under the tree points during motion. The tree angle is often incorrectly fitted to the muscle angle without considering the shoulder angle, which can result in cartilage and nerve damage due to restriction of movement. The gullet plate sits over two opposing muscle groups; the top will contract (pulling the shoulder upwards and getting bigger) while the bottom expands or elongates during motion. This is how the “V” becomes a “U” over the withers.
When it comes to saddle fitting, we need two to three fingers’ clearance at the withers – but all around the withers, not just on top. Under the front of your saddle we find a muscle that extends all the way up into the neck, the trapezius. A tight V-shaped gullet plate results in pinched muscles and a tight neck and back (see Diagram B). A gullet plate that too closely follows the shape of the static wither can also cause this problem (Diagram C).
In most horses, if you take your hand and pinch them on either side of the withers, the back will tighten and drop, and the head will come up. This is not what we want to occur when riding, and is another reason why we want the U-shaped gullet plate fit to the moving horse, and not the static V shape. This area is where the stallion bites the mare during mating to immobilize her – the same effect as a pinching gullet plate, which some veterinarians refer to as the “vice grip” of the saddle. The intuitive reaction of the mare is to stand still, drop her back, and rotate her pelvis in preparation for mating. The rider, on the other hand, is on her back urging her forward. So what to do? Often, this is translated as “reluctance” or stubbornness on the horse’s part and she’s punished with spurs and whips – while it is really only a natural reaction to a pinching gullet plate!
How a naked tree sits on the horse’s withers when standing is not necessarily indicative of how it actually fits when the panel and stuffing are added. Without the panel, the tree would crush the withers and the tree points would dig into the horse’s back (Diagram D). With the panel on, the stuffing clears the horse’s withers and lifts the tree higher. It will actually protect the withers, and the tree points rest in an area where the side of the withers becomes narrow – behind the shoulder (Diagram E).
Tree point direction is also crucial for the comfort and protection of the horse when it comes to saddle fitting. Straight tree points are marginally better than forward facing tree points when it comes to interference with the scapular cartilage. Forward facing tree points can actually cause chipping at the shoulder. The ideal situation is rear facing tree points that mimic the angle of the shoulder (see in Photos A, B and C).