To add variety to conditioning programs, human athletes often undertake exercise sessions that are not specific to their athletic disciplines. For example, long-distance runners might cycle on a stationary bike once or twice a week, swim, or "run" in a swimming pool. This practice, termed "cross-training," has two main goals. First, it provides conditioning of the cardiovascular system (heart and circulation); and second, it reduces the stress and strain on areas of the body that are subject to considerable pounding during heavy single-discipline training.
Does this practice of cross-training have a place in the horse world? Given the unacceptably high rate of musculoskeletal injuries in athletic horses, there is certainly a need for training methods that provide the desired conditioning effect without over-stressing joints, bones, tendons, and ligaments. The end result of this cross-training perhaps could be a reduced risk for injury. In that regard, swimming or exercise on an "underwater" treadmill could be a useful addition to a horse's conditioning program.
Another consideration with the use of swimming pools and other forms of exercise equipment, such as treadmills and mechanical walkers, is the potential to save labor, time, and money. Horses can be exercised without a rider, no special tack is required, and with some exercise methods one can condition several horses in a relatively short period of time. Conditioning on a treadmill or a mechanical walker also takes some of the guesswork out of the training program. For example, the duration and intensity of each workout can be precisely controlled and the underfoot conditions held constant.
We will discuss several pieces of exercise equipment (mechanical walkers, treadmills, underwater treadmills, and swimming pools) that can be used for conditioning horses.
A mechanical walker (sometimes called a "European hot walker") has become an extremely popular tool for light conditioning work. Many large farms and sales prep operations rely heavily on a mechanical exerciser for conditioning sale yearlings. These automatic systems differ from traditional hot walkers in that there is no requirement for the horse to be connected to a lead line (tethered) and pulled by a moving arm. Rather, the exerciser is divided into separate areas (typically six, but there can be as many as 10) by mesh gates that are suspended from horizontal steel beams that form the spokes in the wheel. The gates are 30-35 feet apart, and inner and outer fences define the circular track (approximately eight feet in width). In typical designs, the inner fence has a 60-foot diameter circle, while the outer fence forms a circle with a 68-foot diameter.
Compared to traditional "hot walkers," which were primarily designed for cooling out racehorses after training and racing, the design of the mechanical walker allows more freedom of movement and a greater variety of exercise options. Although walking and trotting are the norm, these machines can operate at speeds up to 20 mph that allow for cantering work. Most have a wall-mounted control box that includes an emergency stop button. By and large, horses adapt easily to exercise in mechanical walkers and mishaps are rare. Nonetheless, these machines should always be operated under supervision.
Mechanical walkers are also reversible, operating in clockwise and counter-clockwise directions. Working the horse in both directions allows for an "even" conditioning of the skeleton and avoids undue stress on the "inside" limbs (particularly the forelimbs). In general, horses should be exercised for no more than 15 or so minutes in a single direction. In this regard, the surface should also be forgiving. Materials such as a mixture of wood fibers and shredded rubber provide the best footing, in my opinion.
Although the initial investment is substantial (as much as $20,000), the time and labor savings for large training and breeding operations can more than justify the expense. The ability to exercise up to 10 horses simultaneously is a huge time saver, with a much lower labor input. Many will use mechanical walkers for both warm-up and cool-down activities, as well as longer-duration light conditioning. These machines can also be used for rehabilitation of injured athletes, although the smooth surface of a treadmill belt (or swimming) is preferable in many cases. Still, for minor injuries, walking in a mechanical exerciser is beneficial and certainly a time saver when there are several horses which would have otherwise required hand walking as part of the rehab process.
As with anything new, the horse needs a gradual introduction to exercise in a mechanical walker. Start with a few sessions of walking (10-15 minutes each). Once the horse is comfortable at the walk, try a few laps of low and medium speed trotting. Also accustom the horse to movement in both directions. When these tasks are mastered, you are ready to incorporate the mechanical exerciser into your horse's overall conditioning program.
The use of treadmills for conditioning horses has increased greatly in recent years. Several different models are available, the main differentiating features being size, speed capabilities, and price. Lower-end models are available for $15,000-$20,000, while some of the higher-end models cost more than $60,000 when installed. The latter are typically capable of speeds greater than 45 mph and are termed high-speed treadmills. These models are necessary if fast work is to be carried out on a treadmill. On the other hand, if the treadmill is to be used only for walking and trotting exercise, the lower-cost models will do the job just fine.
Most treadmills have a hydraulic lift that allows for adjustments to the incline (typically up to 10° of slope). The combination of adjustable speed and incline provides ample variety in a horse's conditioning program.
Use of a treadmill for at least part of a conditioning program offers several advantages. One, the treadmill belt provides a smooth, consistent surface. Many models also have shock absorbers under the treadmill plate, providing a "cushioned" surface. Particularly during the winter months when outdoor surfaces are muddy, frozen, or both, this consistent surface can help prevent injuries from uneven footing. During the depths of winter in northern climes when deep snow or frigid conditions prevent outdoor exercise, access to a treadmill can make a real difference in terms of a training program's consistency.
Another advantage is the ability to control the intensity and duration of a conditioning session. Conditioning can be further refined if the horse wears a heart rate (HR) meter during treadmill exercise. When the HR is in the 140-160 beats per minute (bpm) range, energy is mostly provided by aerobic metabolism; above 170 bpm, there is considerable anaerobic metabolism. Therefore, the workout can be tailored to emphasize aerobic or anaerobic conditioning.
Because the horse is stationary relative to an observer while moving on the treadmill, a trainer can quickly evaluate gait and detect lameness problems, or evaluate improvement in horses recovering from leg injuries. The smooth, cushioned ride of a treadmill is particularly useful for rehab work.
Horses quickly adapt to running on a treadmill, often within three to four sessions, depending on the temperament of the individual horse. Two to three handlers are used during the acclimation process, although fully trained horses can be safely exercised with only one or two people.
The nature of a treadmill workout will largely depend on a horse's athletic discipline and the stage of his training program. For a horse recovering from a tendon injury, initial workouts might be as little as five to 10 minutes of walking, building up to a combination of walking and trotting.
In general, treadmill workouts should attempt to mimic over-ground conditioning, with a combination of slow work (aerobic training) that strengthens the skeleton and improves stamina, and faster work (anaerobic training) that conditions the body for high-speed exercise. Some trainers will require the horse to carry a weight saddle while on the treadmill to simulate normal exercise conditions.
The treadmill is also ideal for a little "cross-training." For example, incline walking and running is useful for building muscle strength (particularly the back and hindquarters) and stamina. Many endurance horse trainers use the treadmill with this goal in mind.
However, no matter what type of training program is used, always remember that a horse can become quite hot while working on a treadmill. It is advisable to provide some type of cooling mechanism, such as a fan, while he is working.
Although some horses (including racehorses) have been successful when trained exclusively on a treadmill, my recommendation is to use treadmill workouts as just one part of the conditioning program--rehabilitation conditioning programs being the possible exception. Regardless of athletic discipline, the horse requires some sports-specific conditioning. Running on the treadmill is not the same as running over ground. Proper strengthening of bones, tendons, and ligaments requires some conditioning on the surfaces faced during competition exercise. Also, the mental attitude of some horses can deteriorate when treadmill conditioning is over-emphasized.
As a suggestion, limit treadmill conditioning to a maximum of 50% of the total training volume, vary the nature of the treadmill workouts to keep the horse interested, and keep each session relatively short (no more than 15-20 minutes). Of course, bad weather and footing conditions might dictate the need for greater emphasis on treadmill conditioning. As well, some horses with a history of low-grade, persistent lameness problems can remain sound when trained predominantly on a treadmill.
A more recent addition to the array of exercise equipment available for horses is the underwater treadmill, commonly called "aquatreds" or "aquacizers." These machines, as the name implies, are a combination of treadmill and swimming pool. A fiberglass tank, similar in width to a regular treadmill, is partially filled with water such that the horse is "submerged" to the point of the elbow (or thereabouts) when standing on the treadmill. The floor of the underwater treadmill has a treadmill belt and the sides are fitted with jet ports that generate water flow during operation.
The underwater treadmill is best used for rehab work rather than as a tool for primary conditioning, so you are more likely to see these machines in large training centers or horse operations specializing in rehabilitation. That said, many human runners who first used water running as a means of injury rehabilitation have continued to include pool sessions in their training program, claiming reduced injury recurrence compared to a conditioning program of all road/ track work. Perhaps the same is true of horses.
As with swimming, the primary goal is to "unload" the skeleton. Buoyancy of the water, in effect, reduces the horse's body weight so there is less strain on the supporting structures of the legs--bones, joints, tendons, and ligaments. Studies in Japan (see Tokuriki et al. 1999) have shown that trotting in a underwater treadmill requires less muscular movement than walking on the same treadmill without water. The authors speculated that buoyancy from the water was greatest during trotting, when the horse repeats up and down movements. Therefore, it is possible that walking is the best gait for exercise in an underwater treadmill, providing some conditioning of the cardiovascular and muscular systems while unloading the limbs.
To my knowledge, no studies have evaluated the effectiveness of underwater treadmills for rehabilitation of leg injuries--for example, tendon bows. Nonetheless, anecdotal evidence indicates that horses which would otherwise be unable to exercise are able to work in an underwater treadmill without deterioration of the primary problem. This will allow for a faster return to full fitness once normal conditioning is resumed.
Swimming was perhaps the earliest version of cross-training for horses. It first became popular in the 1970s and is still widely used today. In contrast to the underwater treadmill, the horse is almost completely submerged (the head stays above water) in a swimming pool that is 10 or more feet deep. Therefore, the horse really has to "swim" (paddling with all four limbs) to propel himself forward in the pool. Research studies and clinical experience indicate that short bouts of swimming (e.g., up to three or four laps of a pool 15 meters in diameter) provides good cardiovascular conditioning. And, because of the complete unloading of the skeleton, swimming is an ideal choice for a horse rehabilitating from an injury. As with the underwater treadmill, horses with a history of lameness problems or older horses with worn joints and tendons can benefit from regular pool sessions.
Of all the alternative exercise modes discussed here, swimming pools represent the largest financial investment. Together with the expense of pool installation, there is the cost of the large building required to house it. As well, there are considerable maintenance costs, and the requirement of very experienced handlers for operation of the facility. So, practically speaking, swimming pools are not a viable option for small training establishments. Still, you might live close enough to an equine swim facility to be able to take advantage of this exercise option.
For those lucky enough to live near the coast or another large body of water, it might be possible to use a beach, lake, or even a river to swim your horses. In some places, ocean swimming is a traditional form of horse conditioning. This is best done in shallow water with fairly even and firm footing--the workout will be very similar to that undertaken on an aquatred. A number of precautions should be taken before undertaking this type of exercise. In particular, you need to evaluate the depth of water in the targeted area and ensure that it is free from debris and provides reasonably firm footing, and also beware of any dangerous wildlife such as water moccasins or snapping turtles. A gently sloping, sandy beach is the best choice.
There are pros and cons to each of the alternative exercises. Regardless of exercise mode, however, it is important to understand that none can completely replace a traditional training program. At least some of a horse's conditioning must be specific to its athletic discipline.
Briggs, K. "Equinomics: Exercise Equipment." The Horse, March 1999, 111-116. http://www.thehorse.com/ViewArticle.aspx?ID=289.
Porter, M. "Indoor exercise in winter." The Horse, December 1998, 85-90. http://www.thehorse.com/ViewArticle.aspx?ID=579.
Tokuriki, M.; Ohtsuki, R.; Kai, M.; et al. EMG activity of the muscles of the neck and forelimbs during different forms of locomotion. Equine Veterinary Journal. Supplement 30, 231-234, 1999.
About the Author
Ray Geor, BVSc, PhD, Dipl. ACVIM, is professor and chairperson of Large Animal Clinical Sciences at the College of Veterinary Medicine at Michigan State University
POLL: Laminitis Experience