Introduction and Background
A top line outline is one of the first things we notice about our horses. They literally carry themselves with its ligaments and other connective tissues. Directly under the saddle are located major muscles that move all four legs and even control bending. Special connective deep fascia tissues link top line bones of spine and ribs, those thin sheaths of fibrous tissue that enclose muscle and other organs. Adding up the Top Line System of our horses gives us a sum of biological materials that have built-in elastic properties. These properties have behaviors called “preflexes” that are able to give a spring-loaded ride! Preserving and enhancing those pre-engineered structures are a goal of training.
Goals to develop a healthy top line will help us ride in comfort and harmony. They are based on exercises that engage the whole horse. A healthy top line is a reward for patience with a range of gymnastic exercises. These exercises are based first bringing comfort to performance and second on improving coordination, balance and suppleness. Finally, we may wish to compete in various equestrian disciplines or ride trails (or both). The bottom line for desired results of an improved top line will come to pass when we recognize the importance of creating calm and good will in our mounts. This entire article assumes that progress toward a more athletic horse is basically a contented horse. A contented horse is safer to be with than an upset animal: each attempt at reaching our goal will be evaluated according to the way a horse responds to training.
Biomechanically useful exercises and their variations are extraordinary tools for developing the whole horse as an athlete. Here is another important point: a top line is connected to the horse’s bottom line in turn connected to legs. Obviously! But the interconnectedness of equine anatomy is what makes exercises work! A plan of action for enhancing a horse’s outline is called a strategy while focusing the strategy on a specific goal is called a tactic.

The Horse as a System showing “preflexes” or built in structures that have a specific role in locomotion.These are “biomechanical freebies” that create elastic movement if they are brought into play with careful planning. Illustration provided by Nancy Nicholson
Riding with a “classical” body alignment is neutral with regard to gravity. Maintaining this posture is a potent influence for the athletic progress of a horse, just by the activity of carrying weight in balance. Further, the gravity neutrality of correct posture allows relaxed, complete, efficient connection through a horse’s top line and bottom line muscles.
Producing a top line that allows optimum athletic performance involves regarding the “horse as a complete system.” A system is made up of connected items, making relations among those items critical. But internal anatomy body parts not in direct view are often “off the radar” of trainers. The brain and nervous system are master controls, receiving sensory feedback from the inside (body) and the environment. Especially important are feedbacks that adapt to balance over footing. That is why a training area should be groomed regularly for basic training. Work over a variety of terrains is specific to equestrian disciplines, after a horse has become capable of training for fitness.
With its brain “running the show,” an attentive, confident and respectful horse is ready to learn. It is usual for a training program to emphasize muscular and cardiovascular fitness, but the hidden connective tissues are at least as important to understand. Planning for connective tissue improvement can be founded on knowing general cellular replacement rates for various tissues. In a sense, trainers are “engineers of biological materials.” These values are approximate for tissues and can vary by age and breed. Blood is the quickest tissue to replace itself within a couple of weeks, muscles are next with tendon and bone taking the longest (perhaps two years for a turnover to new material). Hoof grows at about one centimeter a month and should be supported with appropriate minerals and amino acids.
As elite athletes, horses can “blood dope” by releasing extra cells from their spleen where roughly 30% of their blood is stored. Cardiovascular fitness potential differs by breed, with racing stock having a higher spleen ratio to body mass than non-racing breeds. Further, the preflexes in their legs below knee and hock are central to performance in all equestrian disciplines. These preflexes are activated by unmounted and mounted work in clear gaits. The “freebie preflex effect” comes from built-in elasticity of fascia, tendons and ligaments using gravity potential energy loading that is released to kinetic energy for striding.

Figure 2: “Preflexes” are built in structures that have a specific role in locomotion. These are “biomechanical freebies.” Illustration provided by Nancy Nicholson
An important feature of a training strategy is GRADUAL CHANGE CLEARLY UNDERSTOOD BY THE HORSE. ATTENTION is a first requirement for training, followed by CONFIDENCE as a second requirement. My reasons for describing attention and confidence as basic are simple. if a horse is inattentive, the lesson at hand is not likely to be learned, let alone understood. If the horse cannot understand, its confidence will be limited, and possibly a lesson will be mentally tagged with tension, a problem that could crop up every time an exercise is asked. A distracted, tense or resentful horse might be dangerous to handle. Under tension, muscle contraction/relaxation cycling may not reflect optimal capacity at a particular session. A tense horse will also be crooked because its stronger side contracts more than its weaker side. It is important that a horse “takes its pride back to the stable” after working to expand its envelope of symmetry, strength and flexibility.
PURE GAITS, INCLUDING THOSE OF GAITED HORSES
For now, let’s divide gaits into two categories based on how preflexes work against gravity. These are the non-ballistic or stepping gaits of walking and the bounding or ballistic gaits of trot, canter and gallop. As the graphic of equine gaits indicates, horses can do many kinds of coordinated locomotion. We are interested in basic dressage and trail gaits (including gaited forms of walking). Finally, a named gait has an arbitrary character because we humans have selected specific coordination patterns to emphasize over all the ways horses can cover ground.
Timing of strides per minute (tempo) is critical because biological materials are engineers for appropriate loading and unloading. Think of a spring compressed to some degree: it takes a specific time interval to load and then to unload it. Or consider bouncing a ball at various rates. Materials of spring and ball govern how it reacts efficiently or inefficiently to forces. With horses, a stride rate may be adjusted to create a degree of fitness, always considering that quicker rates have an impact on the chemistry of blood, muscle and tendon. Over-use results in strain and degradation of tissue quality. It is always a delicate issue when probing a horse’s current capabilities. If signs of discomfort appear, an exercise should be halted until its problem is understood.
Pure gaits are essential for training. As the timing diagram shows, dressage has a specific range of timing in the lower left of the diagram. These gaits share some critical features. First, they have four evenly spaced phases, and their TIMING includes silent times as well as the sounded hoof beats. Timing is a foundation quality for developing muscle strength. If a gait description does not include its silent moments, for our purpose here, it is a necessary feature but not a sufficient condition to understand “duty factors.” Duty factor encompasses the length of time that a leg WORKS against the ground. The longer a leg works in support from toe-down to toe-off, the more balance and muscle effort is required. If you would like to convince yourself of this, march very slowly across your riding arena, with expressive knee action.
During this process, you will discover the reason horses prefer to take quicker steps rather than slower: it is less demanding of energy with fewer ground reaction forces of lengthy duration. As we pointed out in “horse as system,” feedback to the brain is very fast!. To gain some sympathy about asking a horse to have slow striding, walk around your arena with the slowest steps you can manage – how quickly it becomes tiring! Be careful with demands for slower tempos, because while they build muscle, too much “drilling” in slow tempos can take a toll on willingness to perform if the horse is made sore.
BASIC BENDING, TO STRETCH AND TONE THE WHOLE TRUNK SIDE TO SIDE
Three things to remember about working on multiple tracks and bending: rider posture, rider balance and riding tact. A stiff or poorly placed rider will create problems for the horse. Why? Because rider weight sits on the “locomotor module.” Supporting these muscles are the bone and cartilage of the elastic rib cage, an often-overlooked part of the Top Line System. “Lat” plus “glute” muscles of the top line can be felt as they relax and contract in the rhythm of a gait. A constantly driving or braced seat with legs exactly parallel will interfere with pure gaits by upsetting balance.
A useful unmounted test will help you understand how your own posture on a horse can be effective or undesirable in terms of helping your horse improve its top line. Stand with your legs parallel and move your pelvis forward and back. It moves both seat bones at once, and that would interfere with the ALTERNATING actions of the locomotor module. Then offset your feet about four inches and then move your pelvis forward and back. Now it will shift seat bones ALTERNATING up/in to down/out. This is automatic and explains why you can comfortably “go with your horse” in any gait if your basic position has your pelvis slightly angled across the saddle. My strategy for flying changes is to have my legs parallel only briefly to alert the horse that a change is coming. This avoids big weight shifts that can cause changes to rock side to side.
Saddles placed too near the withers will create serious problems. Some trainers insist that “this is always the way it has been done,” but this mistake (and it is a mistake) will block bending, cause pain, interfere with the cap of the shoulder blade and result in deterioration of back muscle. In other words, the top line will be damaged. If a horse is developing its top line normally, its saddle should be checked every few months for proper fit and re-stuffed if necessary. It is beyond the aim of this article to give details of saddle fitting, but saddles should never be placed on lumpy stands (use an old cushion or fat towel at least to pad a rack where it is placed). A saddle with a crooked tree is not fixable.
While studies on horses need to be done on blood flow under saddle pressure, MRI data from humans indicate that pressure sores result from diminished blood flow combined with shearing forces, especially in bedridden patients. This could be analogous to saddle pressure responses. In cold weather, always have a cover handy to prevent sudden temperature changes on warm back muscles. In any weather, try not to sit on a horse for too long. As Riding Master Mikola Pawlenko said, “Horses are not chairs!”
Take some time to look at your horse’s back from a mounting block and from behind. If shoulders or hips are showing over- or under-development, it is time to call a massage therapist and then a veterinary chiropractor, preferably in that order. Have the therapist give you a report that your other practitioners can evaluate.
Anatomy of top line development includes shallow muscles as well as deeper structures, including some in the Bottom Line System. In the next two diagrams, a strategically placed rider can influence both front and back sections of top line. This is called the “circle of aids” where the seat bones inform your horse what gait to perform, where to place hind legs in forward work (engagement and collection) and where to reach for the bridle. Your lower leg affects the stay apparatus (especially the serrate muscles) of trunk and neck, sending the horse forward with its poll the highest point.
Bending is an important skill for all lateral work. It is mediated by the latissimus dorsi muscles on each side of the spine under the “lats” and “glutes.” From minimal bend on a 20 meter circle to the bends for leg yield, shoulders-in, half pass and pirouettes and voltes, bending for lateral work and exercises on circles engages mental and physical effort toward a horse’s athletic development. Leaning in through corners and on circles is the signature of a horse that is not bending. Instead, it crosses the inside hind diagonally under its body, producing strain on stifles. Studies on racing greyhounds indicate considerable forces on the inside diagonal pair of legs when cornering. Key to athletic progress is the ability to bend and to carry weight with the inside hind placed under the inside hip when a movement calls for that skill. Because of spine structure, the vertebral surfaces connect in a manner that allows some axial rotation with lateral bend. Direct experimental measurements of bending in the rib cage have been performed in detail. The lumbar spine with long lateral processes of its vertebrae do not bend laterally, but are capable of slight axial rotation.
Advanced bending includes smaller circles (down to 6 meters diameter) and pirouettes in walk, piaffe and canter. For all work plans, try to have variety for the horse to keep its mind with a cheery outlook. All work should be forward and not drilled or over-practiced so your horse never becomes sore or bored.
With pure gaits, basic bending and a working connection understood, your horse has become well enough developed in all its muscles to begin simple lateral work.

The big muscles of the locomotor module (“lats” and “glutes”) are joined by a sheet of fascial connective tissue. These muscles work alternately in the rhythm of gaits. It is important that a rider relaxes and feels the rhythm without exaggerating body motions. A poorly placed or badly fitted saddle can cause injury to these living tissues. Illustration provided by Nancy Nicholson

Photo & Illustration by Nancy Nicolson
LONG/LOW RIDING TO STRETCH AND TONE THE TOP LINE USING THE BOTTOM LINE
Working long and low and in ordinary postures, the contact and its connection through the whole body is comfortably functional (it does not have to be perfect). Long and low work stretches all muscles and is proof of relaxation in mind and body. It must be performed with forward energy to identify your horse’s RANGE OF MOTION in its striding. Time spent with long and low in walk and trot will help refresh work on two, three or four tracks. Rather than discuss these movements in detail here, they are defined and illustrated on the FEI web site in PDF documents.
Pure gaits and transitions among them add coordination to the efforts of good movement. As we discussed earlier, technical aspects of half halts for transitions are the topic of another article, as is teaching piaffe as an elegant air of walking in place. Early, careful attention to tempo will prepare a horse for fluent changes of gait. It is important for riders to realize that asking for changes of any sort requires that the horse be “set up” in a way that tells it what will happen next. Sudden demands are likely to upset a calm training session. They also help release the serratus (forehand, trunk) and hind quarters (hamstring group) portions of the “sleep locks” or stay apparatus the horse uses to nap while standing. These muscles are needed for fluid movement when not asleep.
LATERAL WORK TO CAPTURE ALL THE BENEFITS OF SUPPLING FROM PURE GAITS, BENDING, RIDING LONG/LOW
Changing length of stride from long and low to a lateral exercise as well as stretch of the whole body promotes muscular development in terms of strength and elasticity. Partial pirouettes in walk are especially useful to help riders work toward collection. The bend and placement of the inside hind leg under the inside hip is especially useful for developing all muscles of the hindquarters. I have omitted leg yielding here, because aids for it are different for some authors. It deserves its own section to help readers understand its history and place in a “dressage school” strategy. The earliest I find it mentioned is by a French contemporary of La Guériniérè, DuPaty de Clam. He introduces it head out on the circle! Riding de Clam’s exercise is often tricky for riders not accustomed to absolute control of position.
Finally, with riders using “hyperflexion” and “rollkur” of the top line as riding techniques in the 20th century, a controversy concerning its effects on equine health developed from 1988 onward. Olympic dressage riders were successful at winning medals in an age when digital media made their riding techniques available to anyone with an Internet connection. The International Equestrian Federation (FEI) has produced a number of documents available from their web site as PDFs in response to this controversy over the effects of long periods of deep flexions. While this is a topic so involved that another article is needed, horses worked in deep flexions behind the vertical have demonstrably diminished capacity to engage their hindquarters well under. Riding behind the vertical for more than brief periods disengages the nuchal ligament, over-stretches the supraspinous ligament and pulls the hindquarters out behind. There is a related misunderstanding of “collection” in terms of WHERE a horse places its hind legs to exhibit self carriage: the collected position has hind legs placed under the hip in the plane of the hip. It is “engagement” if the horse comes farther under itself with hind legs without going narrow or wide behind (indicates weakness of the hindquarter muscle system). The most recent document on this subject is the 21 September 2010 Annex XIII of the Steward’s Manual. It recognizes three deep positions of the top line. The only one of these shown in this article is “long and low.”
READ MORE ABOUT AUTHOR DR. NANCY NICHOLSON