One of the most common and incorrect evaluations of damage to the equine loin from saddle fit is muscle atrophy. I am very passionate about this subject because I have come across several horses in the last 16 years who have either been diagnosed with a back weakness from a fall or incorrect muscling or even muscle atrophy when this is not the case when this specific type of damage happens. The worst one I had was a Friesian stallion who would actually get puddles in his back when it rained. My heart broke for this horse and so this is a topic I have been researching and wanting to write about for a long time. But first let’s look at what muscle atrophy actually is:
Knowing this, it is not possible for the pitting and divots we see in an equine back as the result of saddle fit to be actual muscle atrophy. Muscles do not atrophy in sections. What we are seeing is actual damage to the equine back. So what causes these dips and bulges or “saddle shape” in a horse back? A similar effect can be seen in humans who wear pants that are too tight or from bra straps that are too thin in large-breasted women. This is not muscle atrophy at the shoulder and hip of the person but rather the body’s fat shaping around an area of constant pressure.
The cause of these dips in horses is excessive pressure from ill-fitting equipment. I think everyone can understand that. Where it gets tricky is what actually has happened to your horse’s back when these divots form.
Most commonly, this is damage to the subcutaneous fat or adipose tissue of the horses back. There are many levels between the skin and the muscle of every living being. Also from horse to horse the amount of fat stored beneath the skin is different. Our thoroughbreds and quarter horses typically store less fat under their skin. Whereas, morgans, friesians, arabians, and most baroque style horses tend to carry more. That is why this type of shaping in the loin area is much more common in these higher fat horses. The fat cells or adipocytes start getting pushed downward by the pressure of the saddle.
When fat cells get pushed down the connective tissue between the skin and the muscles, the fascia, starts to tighten and harden and as the horse gains or loses weight this fascia seals the fat out of this area of the horses back. Fascia is a system of connective tissue in your body that encases, permeates, suspends and joins your organs, muscles, nerves, bones, blood vessels and skin. In the past it was regarded simply as a strapping and packing material that gave us shape and form. We now know that it does SO much more. When taking a look under the skin, it looks like an omni-directional spider web made of collagen (strong), elastin (flexible) and a liquid gel. Together, these elements provide both strength and flexibility. This material lines every single muscle fiber, every organ and bone, and acts as a structural and communication network throughout the entire body. After an injury new collagen gets laid down in a haphazard manner to help protect the injured site. Since collagen is more rigid, it can create aberrant soft tissue tightness that can limit the function of surrounding muscles and joints.
As a result, unless there is some myofascial release performed on the back the horse will never regain a smooth back regardless of how well a saddle is fitted. However, through good saddle fit, the horse can start stretching more effectively over the back and therefore some of these fascial adhesions may break up naturally and we may see some improvement. More research is being done on fascia and it is now understood that fascial adhesions can cause muscle and nerve pain in both humans and horses. A woman with indents in her shoulders from a poorly fitted bra can experience serious nerve pain as a result. The same can be said for our horse. Common causes of this problem with respect to saddle fitting can include: bridging, a saddle siting too high in front, and the saddle sliding forward during work.
If you start noticing any kind of an unevenness or divot in your horse’s loin it is very important to have the saddle fit evaluated and to invest in some body work for the horse to restore the proper comfort and flexibility to the back.