How does exercising (conditioning) effect the horses’ health?
Volume of exercise.
Progressive loading, designing a conditioning program.
What possibilities of exercising are there? What are the effects?

How does exercising (conditioning) effect the horses’ health?

Cardiovascular System
The capillaries are one part of the cardiovascular system, which is responsible for circulating the blood around the body. With conditioning, the capillarization of the muscles are increased by as much as 50%, which greatly improves the transport of oxygen and energy subtrates to the muscle fibers and the removal of waste products from them. During intense exercise the horse’s oxygen consumption increases by as much as 35 times over resting values, therefore the transport of oxygen if very important. Conditioning a horse will cause a reduction in the heart rate and cardiac output at a given level of exercise.

Respiratory System
Conditioning improves the function of the muscles that hold the upper airways open during exercise, which is very important for the respiratory system. The increase of capillarization of the muscles and skin, which translates into more available oxygen and enhanced cellular respiration, will increase the blood flow to the skin which is important in dissipating the immense heat build-up associated with the exercise.

Energy Production
The longer the duration of exercise, the more the horse relies on fats
(=weight loss), the higher the intensity of exercise, the more the horse relies on carbohydrates. Conditioning increases the concentration of enzymes used to metabolize fats, and this enhances the muscles’ ability to use fats in preference to carbohydrates, which has a glycogen-sparing effect and so delays the onset of fatigue.

Musculoskeletal System
Depending on intensity, duration, frequency and type of the regular exercise, conditioning will always change the structure and chemical composition of the muscle fibers, which has a marked effect on their aerobic and anaerobic capacity ( aerobic e.g. endurance - anaerobic e.g. speed) It does not change the cycle of contraction and relaxation in the muscle fiber (fast of slow) The chemical effects of conditioning involve changes in the enzyme levels and in the amount of energy subtrates stored within the muscle fibers. At the same time there is a shift in the preferred energy substrates favoring the use of fats rather than carbohydrates. The greater reliance on fat utilization has a sparing effect on the muscle stores of glycogen, allowing the horse to go farther before glycogen depletion becomes a limiting factor in performance. The endurance exercise enhances the aerobic capacity, but compromises the power and speed of muscle contraction. Sprinting exercise stimulates the glycolytic machinery
(carbohydrates metabolism) to enhance the horse’s power and speed at the expense of the aerobic endurance (fat metabolism). The conditioning exercises should be tailored to the requirements of the sport to stimulate appropriate adaptive changes in the muscle fibers.

Bones, cartilage, ligaments and tendons adapt most slowly to conditioning and are most susceptible to overloading. Bone is conditioned through a process of continual remodeling. The existing bone reshapes itself and old, damaged bone is removed and replaced. Stress “insults” the bone. The concussion of speed on a hard surface stimulates the bone to develop or remodel. Bone is removed from areas of lesser stress and added to areas of greater stress. While stall bound horses show weaker bone due to less endurance of the stress that builds strength, it is likely that bone strength increases with exercise at slow and especially small amounts of faster more stressful work.

Recent studies in the Netherlands ( EXOC-project= influence of exercise during the first months of life on the development of the equine musculoskeletal system with special attention to osteochondrosis) underlined that osteochondrosis (OC) is for a large part genetically determined, but nevertheless is influenced by environmental factors such as exercise.

Also during studies in the Netherlands it was found that exercise at a young age can alter the biochemical composition of tendons, principally by increasing the cellularity of the tendon, but also by influencing the productivity of the tenocyte hyaluronic acid.

The studies concluded furthermore, that in young horses light exercise affects the surface bone mineral density, which is one important factor in osteochondrosis (OC).

Estrous Cycle
Scott Bennett, DVM, a practitioner who also operates an equine hospital in Shelbyville, KY., and focuses much of his practice on breeding problems, believes, that both exercise and diet can play significant roles in the estrous cycle. Mares can be put under lights to stimulate an earlier onset of the cycle, but if they receive no exercise and either are too fat or too thin, light therapy lone might do little. “I like to see these mares get exercise.” Says Dr. Bennett. “I believe a stall is a horse’s worst enemy.”

Flexibility
The terms suppleness and flexibility are used interchangeably to describe the range of motion about the joints. The range of motion is specific for each joint, and suppleness in one joint does not imply that other joints are equally supple. Indeed, the joints on the left and right sides of the body are not necessarily symmetrical in their range of motion. Stretching or suppling refers to the process of elongating the tissues that restrict motion.
Suppling exercises increase the range of joint motion by reducing tension and resistance in the muscle or connective tissues (tendons, ligaments, joint capsules). For the most part suppling exercises are directed toward the shoulders, hips and vertebral column. It is recommended that the major joints of the neck and back be worked on first, progressing to the upper limbs and finally the lower limbs. Suppling exercises can be passive suppling which involves a slow, controlled movement of a joint to the limit of its range of motion through the application of an external force. Suppling exercises can be also dynamic suppling, which involves rotating a joint rapidly through its range of motion due to muscular contraction or weight bearing, as occurs during locomotion (e.g. circles, voltes, lateral movements, gymnastic jumping etc.)

The conditioning process comprises three distinct, but complementary areas known as cardiovascular, strength training and suppling exercises. Cardiovascular conditioning enhances the ability of the respiratory, cardiovascular and muscular system to produce energy by the appropriate metabolic pathways. Strength training is directed toward the increase of power or endurance of the muscle groups that are important for performance in the specific sport. Suppling exercise increase the range of motion of the joints, which makes the horse more athletic, improves the esthetics of the performance and reduces the risk of injury.

Volume of Exercise
The volume of exercise consists of intensity, duration and frequency. In formulating a conditioning program, these three components are manipulated to provide an appropriate quantity and quality of exercise.

Intensity
The intensity of exercise depends on the amount of energy expended over a period of time. Heart rate is a good indicator of exercise intensity and the use of a heart rate monitor is a practical method of controlling the intensity of a workout. Speed is a major determinant of exercise intensity: the faster the horse travels on level ground, the more energy it expends. At a given speed the exercise intensity is increased by working the horse with more impulsion, incorporating gradients, adding dead weight or working on a loose deep surface. Exercising the horse when the temperature and/or humidity are high also increases the energy expenditure.

Duration
The duration is the period of time over which exercise is performed. The appropriate duration depends on a number of factors including the intensity of exercise and the conditioning objectives, as well as the fitness of a horse. In general, long duration exercise at a low to moderate intensity builds aerobic endurance or stamina, whereas short duration, high intensity exercise improves anaerobic power of speed. For many sports a combination of conditioning formats is used to produce an appropriate balance between the aerobic and anaerobic systems. The usual progress of a conditioning program is to maintain a low intensity of exercise in the early stages, while increasing the duration. The next step is to maintain or reduce the duration as the intensity increases. In the final stages the program becomes more sport specific in that the duration of the exercise periods and rest intervals mimics that of a competition.

Frequency
The frequency describes the number of workouts during a period of time. The appropriate frequency depends on the volume of exercise performed in each workout and on whether the objective is to improve, maintain or reduce the level of fitness. The body needs sufficient recovery time between workouts for tissue regeneration; if the workouts are performed too frequently, there is a risk of injury due to overloading. When the objective is to improve fitness, the recommended frequency for cardiovascular conditioning and strength training is twice or three times a week, with at least one intervening day between workouts. For maintenance, one or two workouts per week is sufficient. Suppling exercises are performed daily throughout the conditioning program and for maintenance.

Progressive Loading

The success of a conditioning program relies on the body’s adaptive response to the stress of exercise. The horse will not increase the level of fitness with the same amount of exercise every day, it only will be maintained. To achieve a conditioning effect, the body must be subjected to gradual increases in the workload. After each increment the new workload is maintained until the body has adapted to it, before the next increase is applied. For cardiovascular conditioning, progressive loading is accomplished through gradual increases in either the duration or speed of the exercise on a weekly basis. In strength training progressive loading is accomplished by a weekly increase in the exercise intensity or the number of repetitions. The suppling exercises are to be increased by a greater degree of stretching.

Designing a Conditioning Program

Each horse and rider or driver are a unique team, and their conditioning requirements are highly individual. Factors to consider in formulating a conditioning program in clued the following:

Horse - breed/type (e.g. thoroughbreds showing the most rapid
Cardiovascular adaptations to exercise)
- age (e.g. in a young horse that is being conditioned for the first
time, progress must be slow to allow adequate time for the
supporting structures like hoof, bone, cartilage, ligament, and tendon
to adapt)
- conditioning history
- present level of fitness
- previous injuries

Rider - time schedule
- competitive objectives

Sport - type of sport (dressage, jumping, racing, driving etc.)
- level of com petition
- timing of competition during the season

If a baseline level of fitness is maintained through a reduced work schedule, reconditioning proceeds much more rapidly the following season. It is not recommended that horses be let down completely, except during recuperation from injury, because large oscillations in fitness are

detrimental to long term soundness. In older horses it is particularly important to maintain fitness in the off season, because reconditioning
takes longer as the horse ages. A long term plan is prepared that maps out the general progress for the entire season. It indicates the desired fitness at different times of the year, together with the timing of major and minor peaks in fitness corresponding to the important competitions. To determine when to start conditioning, the trainer estimates the time needed to get the horse fit, then works backwards from the date of the first competition. An extra couple of weeks are added to allow for a minor setback. The short term plan is a detailed description of daily work schedule, including all the components of the conditioning program integrated with the schooling sessions. It is prepared weekly or every second week and is modified as necessary to take account for unforeseen circumstances, such as lameness or sickness that interfere with progress. The increase in fitness can be seen in monitoring the reduction in the horse’s heart rate at a specific velocity, meaning the improvement in the cardiovascular fitness allows the horse to travel faster at a specific heart rate, which declines more rapidly after the completion of a standard exercise. Temperature stays lower during and after a standard exercise. Lactate, which gets smaller following an exercise, because the horse completes a greater proportion of the workload aerobically.

What possibilities of exercising are there? What are the effects?

Turn-out
This is the most natural alternative for exercising the horse. The horse is free, to work out his own exercise schedule, with the added advantage of eating nearly around the clock, just as nature intended.
Unfortunately, the horse’s environment has changed, it does not have to move for miles to get to different grassing areas or flee from enemies. The horse’s self-exercise program leaves him conditioned only to eat grass and take occasional full out sprints (if size of pasture allows it), with the possibility of injuring himself or being injured by his pasture-mates.

Hand-Walking
This provides a controlled exercise, which could be the start of a conditioning program at the walk.
It is however very labor intensive, time consuming and one will receive hardly any conditioning effect. It is not very effective for strength training, cardiovascular conditioning or suppling exercise.

Lunging
Is used as a preliminary to ridden exercise in young horses and as a training tool throughout the horse’s career. Horses are sometimes lunged as an alternative to ridden exercise, or as a way of maintaining condition. It is a very good tool for conditioning a horse and will improve almost all of the above-mentioned health effects. Lunging should be performed with
side-reins or comparable accessories to develop the correct muscles in the neck and in the back, It should be introduced slowly with gradual increments in the workload to avoid muscular or tendinous injuries, especially lunging on a loose deep surface.
It is very labor intensive and should be performed by skilled labor, otherwise there is a high risk of injuries for the person and the horse.

Hot-Walker
Several horses can be exercised at the same time and the grooms can perform different work in the meantime.
One disadvantage is that the horse is attached at the halter/head. The head is pulled upward, which develops the bottom neck muscles and stains the back muscles. It also encourages uncontrolled walking and trotting, i.e. going sideways and thereby developing the wrong muscle groups or injuring the horse. Statistics show a very high percentage of accidents through rearing, kicking etc.

Treadmill
It is useful in the initial stages of the conditioning program to establish a baseline level of fitness prior to riding or driving the horse as well as maintaining the fitness. The latter is adequate to build fitness and increase muscle mass, especially if the surface is set at an incline so the horse is working uphill. A proper warm up and active warm down is possible and the speed can be increased.
The disadvantage is when the horse works on an inclined treadmill there is a lot of stress on the navicular region ( particular detrimental in horses with navicular disease), as well as an increase of strain on the tendons.

Swimming
It maintains cardiovascular condition and suppleness. Horses use a variety of limb coordination patterns during swimming, and the limbs move through a wide range of motion that is beneficial for suppleness. The heart rates in the pool are generally lower than during galloping exercise. Ways to increase the workload include tethering the horses of having it swim against a current.
Swimming is very taxing on the respiratory system because the chest is totally submerged. It also causes stress on the back, while holding the head high, and this develops the bottom neck muscles. Since there are no ground reaction forces in the pool, swimming is not effective for maintaining the strength of the supporting structures in the limbs as well as improving or maintaining the skeletal system.

Exercise machines
Horses can work:
- as an alternative to ridden exercise to increase the level of fitness
- as a way of maintaining fitness/condition because large oscillations in fitness are detrimental to long term soundness
- reintroduction to work after injury or vacation. This is especially for the bone strength, which returns very slowly compared to the respiratory, cardiovascular and musculoskeletal systems.
- as an active warm up/cool out, especially after high intensity exercise, where lactate accumulates within the muscle fibers. It takes about 3 hours for the lactate removal from the muscle if the horse rests after exercise. However, if the horse performs light exercise, lactate is used as energy substrate for aerobic metabolism. As a result the muscle and blood lactate levels decline significantly faster in horses that are exercised lightly after a strenuous workout.
- warm-up for suppling exercises which should be performed daily throughout the conditioning and maintenance program

It is a very good tool for conditioning a horse and will improve almost all of the above mentioned health effects. The horse can be trained with side reins or comparable accessories. Several horses can be exercised at the same time, which enables grooms to perform different work in the meantime. It should be introduced slowly with gradual increments in the workload to avoid muscular or tendinous injuries, especially on a loose, deep surface. The horse can move freely between the gates at variable speeds, walk, trot or canter. It will encourage forward motion, especially in young horses.
It has been designed and developed in Germany many years ago and established itself as an indispensable training, conditioning and maintenance tool.

Lactate
Is a byproduct of cellular metabolism, which is acidic and damaging to the cells or the body. It must be buffered and removed for normal cellular function to continue. Excess acid levels reduce cellular enzymes and blood ph. This interferes with the normal function of the cellular enzymes and the sodium pump. Acidic condition means that cells can not derive energy by metabolizing important nutrients such as carbohydrates, fats or proteins. This in turn means that the muscle cells can not perform the
Pg 9
normal sequence of contraction and relaxation during exercise. The muscle cells consequently enter a state of suspended contraction or
“tie-up”.

Glycogen
It is the principal form in which carbohydrates are stored in animal tissues,
which is then the fuel used during exercise (Glycogenesis – the formation and storage of glycogen molecules).
Exertional myopathy is caused by a deficiency of high energy phosphates in the muscle cells. Such a deficiency occurs following a period of lactic acidosis or a depletion of glycogen in the muscles cells. The body uses glycogen without oxygen and produces lots of energy, but also lots of lactic acid as well. Lactic acidosis occurs generally after intense high speed or intense short-duration muscle activity.

Carbohydrates
Are a class of chemicals that have certain proportions of carbon, hydrogen and oxygen to produce sugar.
Simple sugars include glucose and fructose
Complex sugars include sucrose, table sugar and starches.
Thiamine (B1) plays an important role the carbohydrate metabolism. It therefore helps to prevent “tying-up” in horses.

Bibliographical References
Hilary M. Clayton: “Conditioning Sport Horses” 1991, ISBN 0-9695720-0-X
Brian d. Nielsen, Cathy Raymond: “Help your horse build better bone” Horse Show, 8/97
Les Selinow: “regulating Estrus” The Horse 12/98
“ Meeting report of the 37th British Equine Veterinary Association Congress” Journal of Equine Veterinary Science, Vol.18, No. 10,1998

For information on the Elite Exerciser please contact:
Hans Kallenberger, President
Elite Equestrian Products, Inc.
9591 Sulphur Road, Sulphur, KY 40070
Tel: 1-800-544-5819, mobile 1-502-487-1004