Regardless of that, no one can dispute the fact that this breed is suffering from an epidemic of bad toplines. However, it’s important to realize that roaching, sagging, dipping and bouncing toplines are merely a symptom. To understand these defects we need to examine the causes. Every part of dog’s anatomy is interrelated like pieces of a puzzle. Subtle changes in one aspect of structure will resound through the entire dog. A weakness in one area will cause other parts of the body to compensate.

Topline problems are rarely due to actual physical curvature of the spinal column. They are almost traceable to some structural weakness of the front assembly, rear assembly or both. Once the dog starts moving, various groups of back and loin muscles are forced do the work that a faulty front or rear assembly cannot. This is why many Cresteds look fine when stacked, but fall apart so dramatically when they get going, especially when they are moved at a trot on a loose lead.

The current standard describes Crested movement as “Lively, agile and smooth without being stilted or hackneyed, comes and goes at a trot.”

Structural problems that cause bad toplines are increasingly obvious when a dog speeds up to a trot. At slower gaits the body is always supported by three legs with plenty of time to make transitions when each foot is alternately picked to swing the next leg forward. “All gaits produce a shock to the front assembly, but if a trotter’s shoulders are correctly placed, this shock passes through them with a minimum effect, being absorbed by the muscles, and there is less rise and fall to the withers and back line, which should be apparent to the eye [ ...] This shock is ever present in the dog’s trot. Some are so constructed as to absorb the most of it while others manifest it quite plainly.” (The Dog in Action, McDowell Lyon)

When speeded up to a trot, the dog must rely on two alternating pairs of diagonal legs for balance, support and momentum. Energy is transferred from the rear to the front much faster. Balance must be maintained by forward momentum with only two feet are on the ground at one time. For maximum smoothness and efficiency, all four legs should be doing exactly the same amount of work at this speed.

On the go round, a trotting Crested is evaluated on the gracefulness and effortlessness of its movement- mainly based on what its topline is doing. In order to smoothly transfer support from one set of legs to the other they must lift and hit the ground simultaneously. Although it is not true for all breeds, a Crested’s topline should remain perfectly level at trotting speed. A slight amount of movement in the topline is inevitable as drive from the rear transfers weight from one diagonal pair if legs to the other. But this should be nearly imperceptible if the dog is well constructed.

A major cause of a bouncing topline is unbalanced front and rear angulation. In this breed, (and many others) excess rear angulation is often coupled with inadequate shoulder angulation. In that case, the lift and forward thrust produced by the front and rear action will inevitably be out of synch.

The Crested standard states “Layback of shoulders is 45 degrees to point of shoulder allowing for good reach.” The validity of 45-degree shoulder angulation is a continuing topic of debate. However, there is not much debate that for most breeds, including this one, it’s desirable for the forearm to be longer than shoulder blade, obliquely placed to slope down and back to the elbow.

The AKC standard is silent on this point although the KC and FCI standards both state that the forelegs should be set under the body. This construction situates the front legs well under the head and neck providing maximum support at the dog’s center of gravity.  Short, straight forearm is one of the most common structural problems plaguing this breed and one of the primary contributing factors to topline problems.

For efficient trotting, the angle of the forearm should balance the angle of the shoulder blade, and as noted, the Crested standard asks for 45-degree shoulder layback. Even though it’s not specifically stated, that implies the forearm should be long enough to create approximately a 90 degree angle between shoulder blade and forearm.

This articulation between the shoulder and forearm not only allows for unrestricted reach and follow through; it produces a smooth blend of neck into shoulder.

The shoulder blades should come together like a tent over the highest point of the thoracic vertebrae. Steeper articulation re creates an abrupt transition at the point where the neck meets the shoulder. This dip at the shoulder can be easily felt. It is clearly visible on a hairless dog and often highlighted by an obvious crease or wrinkle at this juncture. It also creates the characteristic short, choppy steps that often accessorize a bouncy topline.

The length of stride produced by a 90-degree angle between shoulder blade and forearm generates the power to lift the body’s center of gravity as the dog moves forward.  The forearm provides the needed leverage to lift the body and pivot the shoulder blade.

“The great mobility of the shoulder blade as partner to the action of the upper arm, which serves as a lever in lifting and transporting the central body forward as smoothly as possible” (Rachel Page Elliot, Dogsteps) A short, straight forearm deprives the dog of essential leverage forcing it to waste a lot of energy trying to lift its center of gravity rather than moving itself forward. Many Cresteds try to compensate by using their loin muscles to create this needed lift. The latissimus dorsi muscles attach from the loins and last four dorsal vertebrae. They are anchored by tendons to the forearm near the shoulder joint at the other end The cumulative effect of this compensating action is the classic “dipping and roaching” topline of a poorly constructed Crested on the move.

This problem can be somewhat disguised by the popular practice of stringing the dog up tightly on the lead or placing the lead at the side of the neck to force its weight backwards off the front to the rear. But even this won’t conceal it for very long. It is not only an exhausting gait; it also produces an abrupt shock to the front assembly with every step. Wear and tear will show after a couple of laps around the ring

The forearm plays another crucial role in producing smooth gait by absorbing and recycling shock. The length of the forearm has a direct bearing on the shock absorbing capacity of front assembly. Properly constructed, there should be minimal impact as the front absorbs and recycles energy from the rear at a trotting pace. Ideally, the footpad should hit the ground when the leg is fully extended. The shock of impact passes up column of bones through the shoulder blade to coincide with its arc of movement.  “By this action, the head of the blade is not driven straight into the muscle assembly like a battering ram” (The Dog in Action, McDowell Lyon)

There are also a multitude of rear assembly faults that can be directly responsible for topline flaws. One of the most prevalent is known as “rubber hocks.” Inverted hocks, rubber hocks or slipped stifles have plagued this breed for as long as anyone can remember. Many versions of the standard, including the pre 1991 version mentioned this problem specifically. Our present standard does not.

The hock is a hinge joint. It should not move freely in both directions. Rubber hock is a term used to describe hock joints that bend easily forward and backward. Because the joints are inherently unstable, Cresteds afflicted with this problem try to avoid bearing weight on their hocks more than necessary. They tend to repeatedly shift their weight when stacked with their legs extended and prefer to stand with their back feet under rather than behind their bodies.

A dog’s hind legs are not designed to efficiently support its weight. The sturdiest rear assembly is not nearly as strong as the front assembly. Simply give a gentle push to your dog’s shoulders and hips to confirm this. Correctly built, the rear assembly obviously does support a fair amount of body weight but it is mainly designed to generate power.

To produce strong thrust that transfers power directly to body the rear legs must completely and powerfully retract and extend. The hind leg is made up of the thigh bone and second thigh which should be approximately equal in length, and the hock, which should be substantially shorter, straight and sturdy for leverage and stability. “Hocks are the cornerstone of rear assembly” (Pat Hastings, Tricks of the Trade)

A lack of stability at the hock causes the joint to twist rather than push when the leg is flexed. The hock is unable to exert the necessary thrust when foot is on the ground or extend the hind leg rearward for follow through. To try and compensate, the dog may resort to excessive lift of the hind leg at each step or use its back muscles to do this work. Major muscle groups attached to the back of pelvis pull the leg backwards and straighten stifle to produce thrust.  Either choice can explain that classic “high in the rear” topline.

Our current standard does allow some wiggle room for variations and interpretations of correct topline. Human nature being what it is, interpretations often lead to rationalizations to excuse or ignore problems. Before you conclude that a bad Crested topline is simply due to temporary stress or cold, take a closer look at the rest of the dog.