The Advantages of Proper Structure for the Working Dog

By Ricardo E.Carbajal, Chairman – USA Breed advisory Committee

 

Why is conformation important to those of us who are dedicated to the working ability of the German shepherd dog? Why is the USA Sieger Show an integral part of our program to develop and maintain the working attributes of our breed? There is no answer more articulate than this reprint from Schutzhund USA’s Jan/Feb ’92 issue by the head of USA Breed Advisory Committee.

When many people think of a good working dog, they think of a specimen with stamina, high energy, strength and power. Although these are qualities rooted in the mind of a good GSD, too often we forget that the full expression of these attributes depends on the physical package in which it is wrapped. A car may have a finely-tuned engine, but if the tires are flat and the alignment is off, gas mileage will be greatly reduced. In the same way a dog with good working drives but improper structure cannot take advantage of it’s hardware to perform to it’ s fullest potential.

What is “Proper” Structure?
Simply stated, proper structure is the anatomical design that offers the least resistance to movement. In other words, certain physical advantages help one dog perform a task using less ‘Gas’ than other dogs not so well endowed. These anatomical features are described in detail by judges during conformation shows and breed surveys. However, it is important to know not only what good conformation is, but also why it is advantageous to a working dog. To understand the why’s of conformation, we must apply scientific concepts (especially physics and kinetics) to dog movement. There isn’t room enough in this article to discuss every aspect of GSD structure, but we can look at one aspect (rear conformation) in depth as an example of how proper structure affects the working dog.

The Science of Rear Conformation
Forward movement in dogs begins in the rear. The strength of that movement or drive depends on how the rear assembly is designed. In GSD’s rear assembly is defined in terms of angulation, meaning the relatives position of the bones to each other during a certain phase of movement. When we stack a dog for show in the typical “Shepherd stance” we present the angulation of that dog during two phases of movement.

The leg retracted under the body shows the angulation at the moment when the effective push forward begins. The extended leg shows the position of the bones when rear drive is about to end and the leg is lifted off the ground in what is called follow through. The ideal angles called for in most standards refer to those in the retracted leg, and they are as follows:
If that is true, why then do judges look at the dog from the ‘wrong’ side, that of the extended let? A correct dog with it’s leg in the extended position and hock perpendicular to the ground will show two sets of parallel lines: the axis of the pelvic bone (croup) parallels to the tibia (stifle), and the axis of the femur (thigh) parallels to the metatarsus (hock).

These parallel lines are intimately related to angulation. Parallelism is retained through the entire range of motion of the rear leg during the trot; when the leg reaches the position under the body where it is bearing the most weight and begins to push forward (see figure 2), the bones are at right angles to each other as called for the standard. The retracted leg can be stacked adopting different angles, but the hock can fall perpendicular to the ground in only one position. So, judges look at the side that will not ‘lie’ to check for parallelism, croup position, turn of stifle and plumb lines. But is it really true that efficient rear drive depends on the prescribed augulation? Or is it just a capricious decistion of those who control the evolution of the breed?

Ideal Angulation and Strength
Bones don’t move by themselves. The position of bones is important because it directly influences muscle action. Muscle length and angle of Insertion are primary factors for efficiency. Long muscles are better suited for speed, while short muscles provide greater strength. In GSD’s, muscles are neither very long (as in Bulldogs), thus they provide a good balance between speed and strength. The angle of insertion of the muscle into the skeletal frame is most favorable when the line passing through the muscle and tendon is at a right angle to the bone upon which is acting. For example, one of the main muscles contributing to rear drive is the gastrocnemius, as shown in the following illustration:

It attahes to the top of the hock through the Achilles tendon. It’s principle function is to open the lower angle of the rear leg (formed by stifle and hock) thus producing a rear kick and forward thrust. In a dog with correct angulation, the angle formed by the tendon and hock at the time when the muscle contraction is peaking, is an optimale 90 degrees. But what would happen if we increase rear angulation? Most often, angulation is increased when the tibia and fibula (stifle bones) are lengthened. When the stifle becomes longer, the dog’s weight automatically overcomes the strength of the ligaments on all the rear joints. This is due to simple application of physical principals of leverage.

The angle would be more easily bent using the long lever shown on the left than with the short lever shown on the right. Most overangulated dogs have stifles that are much longer than their femurs, therefore the longer ‘lever’ of the stifle overpowers the natural strength of the joints, angulation is increased (becomes more acute), and the dog ‘sinks’ under his own weight.
To open up the angle, the muscle is forced to use greater strength.

The lengthening of the stifle changes the center of gravity of the dog, sliding it backwards and placing greater stress on the lumbar area which is not built to cope with it. It also lengthens the Achilles tendon, reduces the power of the muscle, and above all, disrupts the parallelism (see figure 6)

The Importance of Parallel Lines
Parallel lines offer the greatest advantage in rotational force.
For the two people trying to rotate the bars in the above illustration, the greatest rotational force is achieved when the lines in which they are moving are parallel. Any deviation from the parallel directions of push results in wasted energy. When the stifle and croup are parallel to each other, full force is transmitted by the rotation femur, through the croup, and into the back, thus propelling the dog forward without energy.

Parallel lines also ensure that the plumb lines running through the hocks and femurs are both perpendicular to the ground, offering great stability and correct center of gravity (compare figures 3 and 6). The interaction of parallel lines, correct angulation, good position and length of croup, and strong, well-toned muscles creates a very effective rear assembly capable of delivering the most power in exchange for the least possible energy consumption.

The Future of Our Breed
Other aspects of proper conformation similarly affect the working ability of the dog, especially those related to the front assembly. Although many GSD fanciers remain unaware of this intimate connection, working dogs enthusiasts are nevertheless well-served by maintaining proper conformation through continued judging of their dogs agains the breed standard. Events such as the Sieger Show are much more than a simple ‘beauty contest, ‘they are an important part of maintaining workability in our dogs.

A good GSD is a miracle of careful design and genetic engineering -- body and mind working together as a well-oiled machine. We have many events to help us evaluate mental qualities. Let’s protect the heritage that has been entrusted to us as breeders and competitors and pursue more eagerly the second half of the equation – conformation – demanding fullness of quality and a total dog.

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