Among the animals we call "livestock," horses are unique because they are the only ones we regard as athletes. Unlike other animals that are bred for better milk production or tastier flesh, horses are bred for athletic performance, each type with its own particular talents. Some, like Thoroughbred racehorses, are track and field athletes; others, such as the draft breeds, are weight-lifters; and still others are marathon runners (endurance racers), triathletes (eventers), ball players (polo and polocrosse ponies), or dancers (dressage and reining horses), just to name a few. The demands of the many different sports in which our equine athletes participate might vary, but one thing remains constant--just like human athletes, they need to be fit in order to put in an optimum performance.
Over time, with increased exercise stresses, the body becomes more and more efficient at the process of post-exercise repair.
Many equine sports require a mix of talents. Polo, eventing, and combined driving are just three examples of activities that demand stamina, speed, and flexibility in equal parts.
Horses aren't born fit, of course. Just like human athletes, they must train their body systems to endure increasing strains and stresses, and to bounce back from exercise faster and with fewer lasting effects. This is a process called conditioning.
As our understanding of how various systems adapt to exercise stress has improved (with information often borrowed from the study of human athletes), conditioning programs for horses have become much more exact. But at the heart of it, horses still are very much individuals, so responses to fitness programs can vary widely. A rider's or trainer's knowledge of an individual horse, therefore, is indispensable. In the end, it takes equal parts of science and instinct to tailor your horse's conditioning, as well as knowing what to monitor, what to watch out for, and when to press on or back off.
Goals of a Conditioning Program
Regardless of the discipline in which you'd like your horse to participate, you should be aiming to condition all of his body systems so that they can withstand increasing levels of exercise, without causing any of them to fail. The idea is gradually to increase the amount of exercise stress (a principle called progressive loading) while allowing the body time to adapt to the increased demands.
A conditioning program has three phases.
- Cardiovascular training, which will enhance the ability of the cardiovascular system (heart and circulatory system), the respiratory system, and the muscular system to produce energy by the most appropriate metabolic pathways (more on this in a minute);
- Strength training, which will increase the endurance and/or power of the muscle groups used for a specific sport; and
- Suppling, which will increase the range of motion of the horse's joints, allowing him to be more athletic with less risk of injury. It also can improve the aesthetic grace of the performance, an important consideration for athletes such as show-ring hunters, saddleseat performers, and dressage horses.
Strength training and suppling tend to progress naturally as you train your horse in your chosen discipline, but cardiovascular training ordinarily requires extra attention and effort. We'll go through the specifics of these later in this article.
The success of a conditioning program depends on the body's response to the stresses of regular exercise. Each workout causes tiny stresses, sometimes called "microtraumas," to the tissues of the body. Muscle fibers can strain or tear, ligaments might stretch, and bones will develop microscopic fissures and fractures in response to the repeated impact of hooves with ground. During the rest period following each exercise interval, the body rallies the troops to repair the damage, ensuring that it does not get to the point where it manifests as an actual injury.
Over time, the cycle of damage and repair, which is essential to the conditioning process, leads to tissue adaptation to the work load. Bones gradually become stronger, and joints, muscles, and tendons more flexible.
Other systems also adapt. Strenuous exercise has been shown to have a number of measurable short-term effects on the body, including the rapid use of energy substrates (glycogen and fatty acids, stored from previous meals), which causes a drop in blood sugar levels and depletes glycogen reserves. In addition, metabolic wastes accumulate in the muscle tissues, and if the horse sweats profusely, his fluid and electrolyte balances (essential for the efficient function of muscles and nerves) also can be upset. But between workouts, the body flushes the metabolic wastes out of the tissues, disposing of them in the urine; it also replenishes glycogen stores and hustles to normalize blood sugar, fluid, and electrolyte levels.
Over time, with increased exercise stresses, the body becomes more and more efficient at the process of post-exercise repair. It is essential, however, that there be enough recovery time for the body to make the repairs complete. In most cases, that means an interval of two or more days between strenuous workouts. Otherwise, the accumulated microtraumas can add up to "macrotrauma"--or in other words, a breakdown.
Between strenuous workouts, it is not necessary for the horse to rest completely. In fact, studies have indicated that light exercise probably is beneficial, encouraging the suppleness of the joints. But if at any time the rate of tissue breakdown exceeds the rate of repair, the horse is at risk of injury. Therefore, when you design a conditioning program, it's important not to overdo the workout schedule.
One of the most important things to understand about conditioning is that different systems adapt at different rates. While the muscular and cardiovascular systems of equines respond rapidly to increased exercise demands, the supporting structures (bones, ligaments, cartilage, tendons, and hooves) adapt much more slowly, over a period of many months. As a result, it's crucial to concentrate first on slow work to condition the hard tissues before moving on to more intense work, which challenges the cardiovascular system. If this essential step is skipped, the result can be a horse which appears to be fit, but which is extremely vulnerable to injury because his skeletal structures are not conditioned to take the exercise stress. The progress of your conditioning program will always be limited by the system that adapts most slowly.
"Long slow distance," or LSD, work is the type of exercise that lays the foundation for later fast work, which will condition the soft tissues (the cardiovascular and respiratory systems). LSD involves walking, trotting, and slow cantering for increasing durations of time; many trainers refer to it as "legging up." The repeated, mild impact of hooves with ground at slow speeds is the best way to gradually stress--and eventually re-model--the hard supporting tissues of the body. If done correctly, it should produce minimal fatigue and never failure (injury) of any of the tissues.
The exact schedule of LSD work depends on a number of factors, including the age and previous fitness level of the horse, the climate and footing conditions, the facilities available to you, and the date of the competition you're aiming for. LSD work is particularly important for young horses which are being conditioned for the first time, and the best rule of thumb is to "make haste slowly," with very gradual increases in workload.
It often takes about three months for a young horse to establish a fitness baseline with LSD work, while older horses which have been fit before will adapt more quickly. A horse which previously has been fit, or who is at least partially fit through regular riding before the conditioning program begins, has a head start and might complete the LSD phase in two to three weeks--but it is always best to proceed conservatively. (Interestingly, some studies have suggested that to achieve a maximum response in terms of cardiovascular capacity and musculoskeletal strength, horses should be introduced to conditioning programs at a young age. Immature tissues apparently respond more readily and effectively to the stresses of exercise, and the benefits during the horse's competitive life could be considerable.)
The usual LSD routine is to begin with an exercise duration of about 20 minutes (exclusively walking if the horse is "starting from scratch"--i.e., he has been idle before this), and increasing gradually over a period of about six to eight weeks to a duration of one and a half to two hours. The amount of trotting, and cantering, also can be gradually increased until there might be a total of about 20 minutes of slow cantering in the workout, broken up into several shorter intervals.
LSD work conditions several of the horse's systems simultaneously. While musculoskeletal tissues need task-specific conditioning in order to best adapt to the stresses of competition, bones respond best to rapidly applied forces, applied from a variety of directions. Working on undulating ground and gradients from gentle to steep helps strengthen ligaments, which might assist in protecting bones and joints against sudden forces from unexpected directions (as, for instance, if your horse were to step in a hole). As LSD work progresses and starts to include more canter work, it merges into the next phase of conditioning, aerobic training, which begins to challenge the cardiovascular system.
Phase two of a basic conditioning program is aerobic conditioning, which involves working the horse for a prolonged period at an average elevated heartrate of 140 to 160 beats per minute. (Because horses are individuals, of course, those numbers might vary.) When a horse is coping well with 20 minutes of accumulated slow canter work as part of his LSD routine, he is ready to undertake more serious aerobic conditioning, which alternately increases the distance and the speed of the work.
Most researchers and trainers suggest that aerobic exercise be asked for only two to three times a week. Doing such workouts on a daily basis appears to provide no advantage in terms of how fast a horse becomes fit, and could place unnecessary stresses on the muscular and skeletal systems.
Between aerobic workouts is a good time to do "skills" workouts; for example, an event horse might do a dressage or jumping school, or a polo pony might be run through some of the drills needed to sharpen his game. Once your horse has reached the desired level of fitness, you can maintain his aerobic capacity by doing these workouts just once or twice a week.
Cardiovascular adaptations to aerobic exercise result in a slower resting heartrate, as well as a reduction of the horse's cardiac output at a given level of exercise (meaning that the heart does less work to support the same amount of effort). Blood circulates more efficiently as a result of hypertrophy of the heart muscle, and the blood carries more oxygen to the tissues because it has a higher hemoglobin and packed cell volume (PCV) count. In addition, thousands of tiny new capillaries develop in the muscles, all helping to improve the delivery of oxygen to muscle fibers.
The respiratory system also adapts as a result of aerobic conditioning. Muscles that hold the upper airways open during exercise, particularly the muscles of the nostrils, pharynx, and larynx, respond to allow more oxygen to enter the horse's system, as well as expel carbon dioxide more efficiently. Horses which make respiratory noises at the start of a conditioning program often lose them as it progresses. However, conditioning has little impact on the structures of the lower respiratory tract (the alveoli, bronchioles, and pulmonary capillaries), in contrast to the obvious adaptive changes in most of the horse's other systems. (Researchers have suggested that this means the respiratory system might not be able to match the demands of the other organ systems in a fit horse, and so the respiratory system is regarded as something of a weak link in the oxygen-supply pathway.)
As the workload for your horse gradually increases, he might need to receive more calories in his diet. You might choose to reduce slightly the proportion of fiber in his diet and increase the amount of carbohydrates (in the form of grains) he receives, or you could consider the addition of some vegetable fats to his daily meals.
Aerobic conditioning is a very individual thing. Depending on the level of competition for which you are aiming, you might want to get your horse extremely fit, or just a little fit. His previous conditioning history, and to some extent his breed and build, also will factor in. (As a general rule, cardiovascular fitness improves faster in Thoroughbreds than in other breeds, and any light-boned horse likely will have an easier time of developing fitness than a big-boned warmblood or draft-bred horse.)
You can increase the intensity of aerobic exercise by incorporating hills into your workout, by asking your horse to carry dead weight (a technique most riders now avoid, as it increases the likelihood of a breakdown), or working in deep or yielding footing, such as a sandy beach. Even just asking your horse to work with more impulsion will increase the overall intensity of his effort. Keep in mind, however, that excess heat and/or humidity also can increase exercise intensity (sometimes detrimentally).
Whatever your program, your horse always should be given a 15 to 30 minute warm-up period before he begins his aerobic conditioning, and his workout should be followed by a 10-minute warmdown phase at an easy trot. You probably want to allow about eight weeks for a horse to respond to your cardiovascular improvement program, although some horses respond more quickly than that.
Other Conditioning Considerations
LSD work plus aerobic conditioning will provide most horses with a good fitness baseline from which to draw in practically any competition. But for some horses, particularly those which are performing in "sprint-type" activities such as pole-bending, cutting, or polo, also might benefit from work to condition the anaerobic energy system. Horses use this system while galloping at high speeds, or during any high-intensity exercise; even a horse who is cantering at aerobic speeds is suspected to put in a split-second anaerobic burst from the muscles in the take-off for a jump or a sudden turn. But horses in low-intensity sports, such as show-ring hunters and Western pleasure horses, likely will not need to fine-tune their anaerobic fitness.
The anaerobic system is trained using short bursts of high-intensity exercise, such as cantering uphill, jumping a gymnastic set of "bounce" fences, or performing short sprints from a standing start. This type of work should be used only once or twice a week, alternating with aerobic exercise days.
Interval training is another technique used for high-performance horses, especially racehorses and eventing and combined driving competitors. Derived from training techniques for human athletes, it involves a series of work periods separated by rest intervals sufficient to allow the horse's systems to recover partially. Each work period is relatively short, but the total amount of work performed in an interval training workout usually is greater than in a single high-speed gallop. The partial recovery intervals reduce the possibility of fatigue-related injuries, making interval training a safer and often more flexible way of putting a final edge on a horse's fitness.
During all of these types of conditioning, one of the greatest dangers is failure caused by fatigue. For most horses, "failure" means that accumulated microtraumas become a macrotrauma, and the horse sustains an exercise-related injury. During any type of conditioning work, the rider or trainer must stay alert to signs of fatigue and be prepared to stop the workout immediately if they arise. A fatigued horse which is asked to work at high speeds is at definite risk of a breakdown, because tired muscles are unable to protect the bones, ligaments, and tendons.
Overloading, a general term used to cover both too much exercise stress, and insufficient recovery time between workouts, also can lead to breakdowns. In addition to the risk of injury to bones, cartilage, and other hard tissues, excess aerobic conditioning can overload the cardiovascular system, causing a detrimental increase in the packed cell volume (PCV) of the red blood cells (so that the blood becomes "sludgy"), loss of appetite, and poor performance. Overloading the muscular system can cause muscle strains and tears ranging from mild to severe.
To avoid overloading, don't do the same type of conditioning work two days in a row; watch for early signs of fatigue (reluctance to go forward, lack of enthusiasm, weight loss); and monitor your horse closely for indications of heat, pain, or swelling in his limbs. (More on how to do this in a moment.)
It's also important to remember that fitness, once achieved, is not static. If regular exercise ceases, or is reduced in volume, your horse's fitness level will backslide, although in general, horses maintain their conditioning responses better than humans. Even when in regular, progressive work, horses cannot maintain a "peak" of fitness indefinitely. Riders and trainers at the highest levels of competition know this, and go to great lengths to tailor their horses' conditioning programs so that they reach their peak at the time of the most important competition.
Tapering the workload (easing off a little in duration and intensity) a few days before competition helps ensure that glycogen stores in the muscles are fully replenished, and that fluid and electrolyte balance is restored. This is a particularly useful technique for horses competing in sports that depend on cardiovascular capacity (such as eventing, combined driving, and endurance racing).
Measuring Your Horse's Fitness
Now let's get down to the nitty-gritty--learning to monitor your horse's physical signs so you can evaluate his level of fitness as he progresses through a conditioning program. Doing so is where your instincts and powers of observation become key.
The most difficult phase of the conditioning program to assess is the LSD phase. It is almost impossible to quantify the conditioning response of the hard tissues in living horses (although studies examining cross-sections of cannon bones in deceased steeplechase horses have demonstrated that remodeling and strengthening of the bone matrix are ongoing processes even in older animals). So your best approach is to develop a habit of examining your horse's legs for signs of a workload that has increased too much in duration or intensity. Palpating the lower legs both pre- and post-exercise, on a daily basis, will give you a valuable "roadmap" and alert you to early warning signs such as heat, pain, or swelling.
Hilary Clayton, BVMS, PhD, noted equine biomechanics researcher, recommends the following routine in her book, Conditioning Sport Horses:
1. Begin by laying your palm flat on the hoof to detect any heat.
2. Check the digital pulse on the medial and lateral sides at the back of the pastern. Normally, it will be hard to distinguish, but a bounding pulse is an important early sign of trouble in the hoof.
3. Run your hand down the front of the cannon bones, using your thumb and fingers to feel the grooves between the cannon and the splint bones. (A flinching response from your horse might tell you he is "popping a splint.")
4. Use your thumb and forefinger to feel the superficial and deep flexor tendons in the back of the leg, as well as the suspensory ligament. They should be cool, tight, and free of swelling.
5. Lift the leg to palpate the tendons and ligaments more thoroughly. Each one can be manipulated individually when the horse's leg is in this position. Any further heat, swelling, or pain merits further investigation by your veterinarian--and at least a temporary halt to your horse's workouts.
You also can glean a lot of information from your horse's general demeanor and attitude. If he is deriving the appropriate benefit from his LSD work, he will be alert and enthusiastic about his workouts, will be developing good muscle definition and shedding excess weight, and will have a good appetite. At the first sign of undue fatigue, throttle back on your progress. While it's good to have a plan in place, a thinking trainer must be prepared to alter it at any time in response to the horse's reaction.
Once you introduce aerobic conditioning to your horse's fitness routine, you'll need to start paying attention to another important indicator: his heartrate. The heartrate (or pulse) is the single best indicator of exercise response. As a horse's aerobic capacity improves, you'll notice two things: a reduction of the heartrate (both at rest and when exercising at a certain level), and a faster return to the resting heartrate after exercise ceases. In a healthy horse, the heartrate should return to resting levels (about 28-40 beats per minute) within 20 minutes after trotting exercise, 40 minutes after slow galloping, and 60 minutes after fast galloping (depending on the heat, humidity, and to a certain extent, altitude). The more quickly the heartrate returns to a resting level, the more fit the horse.
Measuring the heartrate is not difficult, but it does require a little practice. There are several sites where one can take a pulse on a horse, but the most convenient ones are the facial artery and the digital artery at the back of the pastern. The facial artery winds over the edge of the jawbone just in front of the horse's cheek. If you stand on the left side of your horse's head and feel with fingertips, you should be able to feel it on the inside of the jaw bone, underneath. It feels like a small tube or cord which rolls under your fingers. Hold your fingers lightly over the artery to detect the pulse, which is soft and slow at rest, but a good deal easier to feel after exercise when both the rate and the blood volume increase. Most trainers count beats, or pulses, for 15 seconds and multiply by four to get a beats-per-minute rate. Longer intervals probably would be interrupted by the horse fidgeting or chewing.
The digital artery runs over the sesamoid bones behind the fetlock and continues down the back of the pastern. As mentioned previously, its pulse might be hard to detect at rest, but after exercise, it is a useful site. Obviously, however, a rider must dismount to take a pulse from either of these arteries (and bending down to take the digital pulse might mean you have tenuous control of your horse). There is one site that can be reached from the saddle--the small dorsal scapular artery that runs below and in front of the withers, about six inches from the top of the shoulder. In practice, unfortunately, this artery can be extremely hard to locate, and might be covered by saddle or saddle pad.
Penny Rowland, DVM, a practicing small-animal veterinarian and Intermediate-level eventing competitor, says that the use of a stethoscope simplifies her assessment of her horses' heartrates. She often carries one in a pocket while conditioning her horses, and quickly dismounts at the end of the exercise interval to place the instrument on her horse's barrel, just inside the left elbow. "You don't need a top-quality stethoscope," she says, "because you're not listening for the quality or the character of the beats, just the number. You can get one for about $20 or $30."
One major disadvantage to taking a pulse, either with your fingers or with a stethoscope, is that in the time it takes to pull your horse up, dismount, and find the right spot, his heartrate is plummeting--so you don't get a truly accurate picture of the rate at which he recently was working. Heartrates that climb over 200 beats a minute during exercise can drop to below 100 beats a minute in the blink of an eye in a fit horse.
The only true way to get an idea of your horse's working heartrate is to employ an on-board heartrate monitor (cardiotachometer). This instrument detects the heart beat using two electrodes that are held against the horse's barrel by his saddle or harness. One is placed in the midline of the chest under the girth, and the other is positioned on one side of the withers, to detect the electrical signals generated by ventricular depolarization. The information is relayed to a readout device, which displays the heartrate in beats per minute. Depending on the design of the monitor, the readout might strap to the rider's wrist like a watch, be attached to the front of the saddle, or be worn on a wide band that wraps around the rider's thigh.
The major advantage of a heartrate monitor is that it gives you a continuous reading of your horse's heartrate before, during, and after a workout. When a horse pulls up from a fast gallop, the heartrate falls most rapidly in the first minute, and thereafter at a slower rate. That rate of reduction in the first minute is an excellent indicator of fitness and only can be measured with the monitor, since no rider or trainer could locate and measure the horse's pulse that quickly. Using a heartrate monitor also can help you assess whether your horse is working aerobically or has crossed the "anaerobic threshold," which usually occurs somewhere around the 170 beats per minute range. If you want to ensure he's working aerobically, target his workout so that his heart works at 160 beats per minute or less.
In addition to its use in everyday conditioning, a monitor also can tip you off to early signs of trouble. Pain elevates a horse's heartrate, and many horses with a "pre-lameness" condition will demonstrate an elevated heartrate even at a trot. So, if you know what your horse's usual heartrate is at a given rate of exercise, any significant increase in that will tell you that now is not the time for a serious workout. Heartrate monitors are not inexpensive, but their prices have been dropping in recent years; a basic one can be purchased for about $300 to $400. When you buy, however, check that the monitor is designed for use on horses. Some designed for humans might be inaccurate at heartrates over 200 beats per minute, and a horse in serious work can achieve a maximum heart-rate of more than 240 bpm.
What should you be looking for when monitoring the heartrate? Rowland says she checks both the heartrate immediately after exercise, and the rate of recovery. "That rate of return (to near-resting levels) is the most important thing," she explains. "I want my horse's pulse to return to 80 beats per minute or less within ten minutes of finishing our workout. Sixty beats per minute is even better."
A horse whose pulse does not return to this level within 10 minutes probably has been unduly stressed for his current level of fitness. This is a sign that the trainer should back off a little until that recovery rate can be achieved easily.
While Rowland agrees that a heartrate monitor can be an extremely useful device, she cautions that it is tempting to take the numbers it generates as gospel. "It's important that the heartrate does not become the only benchmark (of fitness)," she says. "You have to continue to use all your senses and monitor the whole horse."
What else should you look for? Respiration is one important factor. The normal resting respiratory rate of an adult horse is about 12 to 20 breaths per minute, but that can increase to as much as 180 breaths per minute under heavy exercise. At the canter and gallop, breathing is linked directly to the stride rate, a situation that is called locomotor:respiratory coupling. When exercise ceases, the horse usually will take a few deep breaths, then allow his respiratory rate to settle in the range of 60 to 100 breaths per minute until his oxygen debt (the amount of oxygen demanded by the tissues for recovery) is repaid.
"I don't usually count respiration, but I do use breath frequency and sounds as a general indicator of recovery," says Rowland.
Flared nostrils and rapid, heavy breathing immediately post-exercise should return to a more normal breathing as the heartrate drops; any unusual noise or discharge can be a sign of trouble. In hot and/or humid conditions, horses might use shallow, rapid breaths as a method of cooling themselves by passing large volumes of air through the nasal passages, where large quantities of blood vessels are available for heat exchange. Observation of both the rate and the depth of respiration, together with the heartrate and rectal temperature, is crucial for determining whether a horse is overheated after exercise; the respiratory rate alone is not a good indicator of recovery.
Of course, you should continue to monitor your horse's legs throughout his conditioning program, taking any small sign of trauma as a warning flag. It is far better to take early, small indicators of trouble seriously, than to press on and risk serious injury. The savvy trainer will consider the well-being of the whole horse throughout a fitness program--his attitude and his appetite, the sheen of his coat, and the weight he carries all can tell you whether he is suffering from your demands, or thriving on them.
About the Author
Karen Briggs is the author of six books, including the recently updated Understanding Equine Nutrition as well as Understanding The Pony, both published by Eclipse Press. She's written a few thousand articles on subjects ranging from guttural pouch infections to how to compost your manure. She is also a Canadian certified riding coach, an equine nutritionist, and works in media relations for the harness racing industry. She lives with her band of off-the-track Thoroughbreds on a farm near Guelph, Ontario, and dabbles in eventing.
POLL: University Equine Hospitals