Conformation, saddle fit, rider body weight, and training practices can all influence your equine athletes toplineEven without a rider, a horses back must support the weight of the thoracic and abdominal organs, as well as ingesta. | iStockAn equestrian who sees a lame horse often has an instinctive, knee-jerk reaction to blame the limbs. Which leg is it? often precedes the bigger question of, Is it a leg? Thats understandable, considering the most common causes of lameness do originate from the limbs, with arthritis, tendon and ligament injuries, hoof abscesses, and podotrochlosis (navicular disease) being some of the most frequently diagnosed. In reality, however, legs are not always the sole culprit. Many cases of equine pain, lameness, and poor performance stem from a problem higher up. And because the spine is at the center of the horses locomotion, any problem that originates in the back or sacroiliac (SI) region can have repercussions throughout the body, legs included.As a sports medicine veterinarian, I am asked to evaluate a fair number of performance and lameness problems, says Cooper Williams, VMD, Dipl. ACVSMR, Certified ISELP Instructor, owner of Equine Sports Medicine of Maryland, based in Hampstead. A large percentage of these performance problems can be attributed to conditions involving the axial skeletonneck, back, and pelvis. In this article well look at the factors that affect functionand dysfunctionin your horses topline.The Ridden Horses ChallengeThe equine species was not designed to carry humans, much less perform athletically while doing so. The horses back is made up of 18 thoracic and six lumbar vertebrae, and it is the rigidity of these sections of the spine that makes riding possible. Nonetheless, some ridden horses experience dysfunction, injury, and pain despite our best efforts to provide proper care and maintenance.Preventing back pain in horses is challenging, says Kevin Haussler, DVM, DC, PhD, associate professor at the Orthopaedic Research Center in the College of Veterinary Medicine & Biomechanical Sciences at Colorado State University, in Fort Collins. As well discuss, many factors can increase the risk of back pain; it is difficult to adequately manage them all, especially as we push horses to perform at their highest possible athletic potential.Does Conformation Really Matter?Think of the horses back like a suspension bridge anchored by the pillars of the front and hind limbs connecting at the shoulder and sacroiliac joints, respectively.Lets start with an analogy. Williams encourages us to think of the horses back as a suspension bridge. This bridge consists of the main structural elementthe spinal columns vertebraeand support struts: muscles, ligaments, and tendons. The front and hind limbs are the pillars that anchor the bridge into the ground, connecting via those soft tissue struts at the shoulder and the sacroiliac joint, respectively. Even without a rider, this living bridge is being asked to support a significant amount of weight because of the sheer mass of thoracic and abdominal organs, as well as ingesta, Williams says.Riders often believe horses with long backs are more prone to back pain than those with short backs. Thats because physics tells us the greater the space between the pillars of a two-pillar suspension bridge, the weaker the bridge. But our sources are hesitant to jump to conclusions regarding back conformation. There isnt currently good scientific evidence to support this claim, says Haussler. A measurably longer distance between the withers and pelvis does not automatically mean that the back is weaker or more prone to injury. Thats mainly because muscles play a vital role in providing strength, support, and movement of the back. The horses ability to comfortably carry a rider depends more on proper muscle function than on isolated conformational features such as back length. This is promising because while you cant change conformation, you can improve fitness.The same goes for horses with swayed backs, a condition known as lordosis. Conformation relates to structural features such as size, shape, and contours, explains Haussler. However, posture is just as important when we discuss back pain and dysfunction from long or swayed backs. We will never be able to change the relative length or angle of the horses back, but we can improve function by building muscle strength and core stability with tailored exercises.When talking about conformation, we must be careful about rules, adds Williams. Having been a lifelong horseman and a veterinarian for close to 40 years, I realized over time that every time you set rules on what is optimal, individuals break those rules. Proper conformation and its evaluation are very subjective. The phrase ride the horse, not the X rays has become popular in the sport horse world for that reason.This being said, radiographs and other diagnostic modalities do play important roles in evaluating a horses particular back and sacroiliac anatomy and, therefore, potential dysfunction. Imaging is useful when the horse faces a soundness or performance problem and also helps prospective buyers make informed decisions during prepurchase examinations (PPEs).Aside from the conformation faults such as long or swayed backs that we can see from the outside, there are several internal developmental abnormalities that can play into back problems in horses, explains Williams. These include spinous process impingement (kissing spines), an extra thoracic rib or extra lumbar transverse process on one side only, and congenital ankylosis (fusion) of a (spinal) disc, for example, he says. A key concept here is that asymmetrical structure leads to asymmetrical function, which increases the wear and tear on our structures and can predispose the horse to back dysfunction and pain. There are also acquired issues in the back and sacroiliac region that can result from falls or other injuries.Our sources recommend working with your veterinarian to discuss potential limitations a horse might have based on conformation faults and your riding goals. They agree that how a horse is asked to use his back, the duration and intensity of exercise, and horse-rider interactions are likely much more relevant than conformation flaws.The Importance of FitnessThis leads us to our second point: The role of physical fitness in proper back function. For horses to successfully carry us on their backs pain-free, they require strength, flexibility, and good back muscle development, says Haussler. Lack of proper musculature increases the chance of injury during exercise. But achieving proper fitness takes more than simply riding.Youll need tailored exercises and training to improve strength and endurance, as well as stretching and chiropractic care to improve flexibility, he explains. If the horse does develop back or sacroiliac dysfunction, youll also need acupuncture and rehabilitation to manage the pain and any muscle atrophy (wasting).Carrot stretches are perhaps the most simple and accessible physiotherapeutic exercise for owners to improve topline musculature in their horses. In a 2013 study Rodrigues et al. found that consistently performed carrot stretches increase the size of the stabilizing muscles in the horses back, effectively building topline.Rider Body WeightUnsurprisingly, the tack and rider collectively have a monumental impact on the ridden horses back function. As discussed, the horses back naturally supports a significant amount of weight, even when not in work. Then, we add a rider, a potentially heavy passenger constantly shifting positions, says Williams. Riders have different riding and athletic abilities, not all optimal. Many researchers have explored the intricate horse-rider relationships with regard to each individuals biomechanics and musculoskeletal function.In 2019 Dyson et al. examined the influence of saddle fit and rider weight on horse gaits and behavior and concluded that large riders could induce temporary lameness and behaviors associated with musculoskeletal pain. The authors recognized lameness associated with the riders weight is a multifactorial issue: The horses age, fitness and muscle development, conformation, speed and duration of exercise, and the riders skill, balance, and coordination can all affect the ridden horses musculoskeletal health.Interestingly, rider body weight guidelines in the United States are not the same as those in European countries. In the U.S. we generally consider it acceptable for a horse to carry up to 20% of his own body weight. That means a 1,000-pound horse could carry a rider and tack weighing up to 200 pounds. In most of Europe, equestrians are instructed to follow the much stricter 10% rule, by which standards the same 1,000-pound horse could only carry a 100-pound rider. But its not so straightforwardbased on social media and forum discussions, Europeans themselves criticize this guideline as overly restrictive and unrealistic for many horse and rider combinations.Science hasnt been able to produce a numeric acceptable vs. unacceptable cutoff for rider weight, our sources say, largely because many factors, from horse and rider fitness to saddle fit, can affect an individual horses ability to comfortably carry a particular rider. The horses own weight and fitness also affect his back function. Metabolic issues and weight management are another huge issue, no pun intended, says Williams. An overweight horse cannot perform as an athlete and hold up over time.Saddle FitRelated Content: Understanding Saddle FitDifferent saddle types and construction induce variable pressures under the saddle, says Haussler. English saddles typically have a much smaller contact area on the horses back than Western saddles, spreading the pressure across a smaller part of the horses back. He adds that treeless saddles, which are very popular in some riding communities, have been found to produce higher peak pressures over an even smaller area because they lack a tree to distribute the pressure evenly across both sides of the thoracic back.Saddles must not bridge (lack contact in the middle), rock (poor contact in front or back), or shift from side to side, adds Williams.Horse and Rider BiomechanicsEven if the saddle fits the horse well and the riders body weight is deemed appropriate for that horse, there is no guarantee that back dysfunction wont happen once the pair is in motion. The locomotion of both equine and human partners greatly impacts the horses back function. In 2019 Gunst et al. found that rider posture and horse movement, the latter of which often relates to conformation, can cause asymmetrical force distribution across the horses back. For example, if the rider collapses one hip at the sitting trot, his compensatory weight-shift into the opposite hip and leg increases the force on that side of the horses back. Over time this can cause pain and dysfunction.The Impact of TrainingMuch like different saddles have different effects on back function, so do equestrian sports. Disciplines are quite varied in the type, intensity, and duration of ridden activities, says Haussler. In barrel racing, horses are required to produce very rapid acceleration and deceleration movements with sharp turns, which demand trunk strength, flexibility, and agility. Show jumping requires impulsive hind-limb movements to carry the horse and rider over the various obstacles and forelimb support during landing, both of which directly involve the back and sacroiliac joint. Dressage requires long bouts of training to develop core stability and fine motor control, increasing the risk for chronic repetitive-use injuries of both the limbs and the back.Working with a reputable trainer and listening to your horse are our sources top recommendations for mitigating discipline-related back dysfunction in equine athletes.Starting the Conversation About TreatmentMaintaining a healthy, pain-free topline in a ridden horse might be challenging for some but, in todays world, horse owners and veterinarians have an abundance of therapeutic modalities available to them.Chiropractic, acupuncture, and other bodywork modalities can help, and so can devices such as functional electrical stimulation (FES), pulsed electromagnetic field (PEMF), therapeutic lasers, and shock wave, says Williams. We also need to think about changes we can make in how we ride and train our equine athletes to help prevent the recurrence of back and sacroiliac pain. Many are common sense: Working the horse in moderation, not overriding and overtraining. Taking the time to do proper warmups and cool-downs. Williams recommends the book Activate Your Horses Core for extra guidance and education.Final Thoughts One of the most overlooked aspects of horsemanship is a failure to listen to the horse, says Haussler. Horses communicate in their own highly developed manner, and we need to listen very carefully to what they are trying to tell us and respond appropriately if we are to help prevent back pain or other injuries. Only with thoughtful management, paying attention to the horse, and a comprehensive program provided by a team of practitioners can we minimize the detrimental effects of back pain and optimize the equine athletes comfort and performance.