Conditioning After a Lay Off
Conditioning After a Lay Off
Gayle L. Ecker
During training sessions, we plan very carefully to prepare our equine athlete for the selected task. We observe, record, and follow its progress, but despite this care there are always setbacks due to illness, lameness or other unforeseen problems causing layoffs. Once the problem has been solved, there comes the task of returning the horse to previous condition. This must be achieved without aggravating or causing the return of the problem which caused the layoff in the first place.
"Training" (or conditioning) implies that the systems of the body, the musculoskeletal, nervous, respiratory and cardiovascular systems, etc., have an improved ability to handle the demands of a workload and subsequently to recover from those demands with a minimum of time and without injury. "Detraining" of course implies the opposite, the horse is less capable of handling a set workload over time, there is a greater chance of injury and recovery will take longer.
In order to assess the loss in "fitness," we must rely on experience, observation and what research information can tell us. It is important to realize that research on detraining (and retraining) is typically done on healthy horses, free of problems, and that effects from illnesses could add other detrimental effects.
Effect on bone
One of the major factors in the bone's ability to tolerate stress is the density of the tissue. In general, the greater the density of the bone the greater the bone strength. Bone density increases rapidly in the first 12 months of development and more slowly until three years old. After three years of age there is very little change due to growth in normal horses. Training programs cause an increase in bone density in the legs due to the stresses imposed by the concussive forces and weight bearing and this increased density helps the bone withstand the stress. There is still a great deal to learn about optimal stress loads during exercise programs. Various training programs of greater than eight weeks duration have shown significant increases in leg bone density, particularly in young horses.
Bone density can be dramatically affected by a prolonged period without weight bearing, which can be the result of injury. After eight weeks of immobilization with a cast on a forelimb, mineral loss in bone occurred in both front legs of a horse but more was lost in the casted leg. This is a reversible process as bone density is regained when full mobility and training is restored. The more serious the injury and the longer the recovery period, the more reduction in bone density will occur. More time will then be needed to build up the bone density when training resumes.
There is not enough information available to provide specific guidelines for training aimed at improving the skeleton. Bone quality is particularly difficult to assess objectively. This is an area of research which the ERC is commencing to address. It is suggested to keep the program varied: alternate hard and soft footing, hills, turns and corners and speeds. The conditioning program must be maintained at a level where the bones, ligaments and tendons can keep up with the pace of training. Your veterinarian will have an important role to play in these decisions. In the context of tendon injuries, ultrasound scans can provide valuable information for decisions on training programs. Care must be taken to examine the legs frequently for any signs of heat, swelling or pain. When the bones are ready to move on to the next phase (and this could take 4 to 6 months depending on age, type and length of layoff, etc.), then other systems will be ready too.
Effect on muscle
Muscle is one of the body's most adaptable tissues. Some of the important changes that occur in muscle are listed in the table below. The fast adaptation time of muscle may cause us to become less cautious. The horse feels good so why not let him go? The answer, of course, is that the bones, ligaments and tendons may not be ready; a lesson that many of us have learned the hard way. It is important to remember that although muscle adaptations have begun to take place in as little as one or two weeks, the bony structures take much longer.
Training adaptations that occur in the muscle
There are enzymes in the muscle which control the rate of provision and consumption of energy. Training programs can increase the rate of activity of these enzymes. Enzyme activities were increased over 40% in human athletes following eight weeks of training. Detraining for the same period practically reversed all of the gains. Detraining effects have also been demonstrated in as little as four weeks.
The effects of detraining following strength training are not well studied. More work has been done on detraining in humans due to immobilization, but it should be kept in mind that more often there is reduced activity rather than complete immobilization, which may help reduce the training losses. Effects of immobilization can be profound with noticeable atrophy of the quadriceps in just a few weeks. These effects are mainly due to loss of size in fibers and fortunately these effects are readily reversible with training.
Effect on the cardiovascular system
The heart rate (HR) is a useful indicator of the stress of the exercise and the ability of the horse to recover from that exercise. As the workload increases, the HR will increase. Once the exercise stops, the HR will return to pre-exercise levels, but it will take longer following harder workouts. With training, the HR for a given exercise will be lower and the HR will return to pre-exercise levels faster.
During intense exercise, lactic acid will be produced in the muscle as a byproduct of high energy consumption. This substance is picked up by the circulatory system. It can then be measured as "blood lactate" to give an indication of the stress of the workout. Following training, there will be a lower blood lactate for a set exercise protocol. This measurement can be standardized by use of a test called a VLA4, which has been used by several researchers. The test measures the speed of the horse that produces a blood lactate of 4 mM. Following training, the test speed will increase.
Fitness losses as judged by heart rates and blood lactates may not be as substantial in horses as in humans. In one study with five weeks of training, followed by five weeks of detraining, the mean treadmill speed at a HR of 200 beats per minute (bpm) was not significantly different than that following the training period. The authors concluded that five weeks of detraining did not reduce fitness as judged by recovery heart rates. Other researchers have found no increase in venous blood lactates for a set speed following five weeks of detraining, however, a decrease in VLA4 was observed following eight weeks of detraining, but it did not decrease to pre-training levels. It appears that a few weeks off is not as detrimental to the training status of the horse's muscles as it is in humans, however, further research studies are necessary to contribute to our complete understanding of the detraining response in the horse and to confirm the results of these studies.
Consider alternate training avenues
Pool training can be useful for the rehabilitation of horses following a layoff However, this may not be suitable for all circumstances. The weight of the horse is supported by the water, therefore swimming may use different muscles than those stressed on the track or under saddle. These muscles may not be ready for certain types of exercise following pool training. Extended pool training should be followed by a period of slow long distance before increasing the intensity or by alternating pool and track training if possible. This is recommended to condition the muscle.
Treadmills are quite useful as they allow the intensity of the workout to be controlled by changing the speed, and incline. Use of the incline can be helpful to build muscle bulk. But be aware that in incline can cause damage to tendons and ligaments and cause muscle soreness if not introduced gradually. This can be a problem on fixed-incline treadmills. The surface of the treadmill can be hard on the legs, so care must be taken to introduce the work gradually so the bones can adapt to the new stress. Treadmills that operate underwater are relatively new to the training scene, but offer the advantage of maintaining fitness levels while minimizing, but not eliminating, concussive forces on the legs. Again, care must be taken before reintroducing the horse to its normal training program.
Record your observations and the horse's response and recovery!
If you have kept records on the initial training program, now is the time that you will receive extra dividends for your efforts as you monitor the horse during the retraining phase. You will have a previous pattern established for that individual which you can use to compare the recovery HR following the training sessions. This information will be invaluable to help prevent pushing the horse too far, too fast.
To eliminate some of the guesswork, make use of a HR monitor. There are several models to choose from and they are well worth the money if you are doing high level training. If a HR monitor is out to the question, then make use of a stethoscope and stopwatch. Start monitoring the HR of your horse before you get into serious training so that you are completely familiar with the normal range of response. The testing HR should be between 30 to 40 bpm but horses do vary, so learn what is normal for your horse. Elevations in resting HR can indicate illness or pain in the absence of excitement. At HR below 160 bpm, the work will be predominantly aerobic. The anaerobic system begins to take on more of the burden of energy production as the heart rate starts to go above 180 to 200, at which time blood lactates will soar and time to fatigue is about one to three minutes depending on the fitness of the horse. Maximum HR is between 210 to 240, therefore, for safety reasons, the maximum target HR should not be over 180 bpm unless specific training demands require this level of intensity.
Make sure you monitor recovery HR. In about five minutes, the HR should be approaching 60 to 70 bpm depending on weather and surface conditions, fitness, stress, and rest period activity. If at 10 minutes the HR is still around 100, the stress may have been too high for the horse at this stage.
After a prolonged layoff, the first goal is to reestablish the ground work by spending lots of time walking. Start with 20 minutes and build to one hour or more over the next three to four weeks if the horse is handling the work easily. Add short durations of trotting, about two to three minutes each and build up the time as long as the HR comes down quickly. If the HR remains elevated following the trotting, then back off again for a week and check for any other problems. Add exercises to supple and balance the horse during this time.
Once the horse is responding well, when he is loosened up and recovering quickly, start to increase the duration of the trotting. Heart rates should not be high (less than 150 bpm) during this time period and if you start to see "drifting" upwards of the HR, then there may be a problem developing. Reestablishing a sound base may take around two to six months depending on the layoff and reasons for it, and this allows "catchup" for all the tissues and systems. When the aerobic system has been trained and recovery times are good, then it is time to introduce some progressively faster intervals, and gradually push the capacity of the systems to work at higher intensities. The demands of your specific sport will dictate this part of the training, but once you have regained that base, you may start on the training program at the same pace as you did initially, always monitoring the response of the horse and recovery times. Strength training and high speed work are gradually introduced once again with the same care as before the layup. Intense work should only be done twice a week with an easy day following the hard days and at least one or two days off per week with pasture exercise.
Retraining following a seasonal layoff
So far we have discussed layoffs. due to a problem. The owner or trainer may elect to lay off a horse to give it a rest between seasons or because the winter weather makes training difficult. Starting a horse back after this type of layoff is less complicated as there was no physical problem. In order to save time on retraining, keep the horse outside in a group of horses as much as possible, and continue with light exercise once or twice a week including lots of variety. This will not only keep the horse "mentally fresh," but will also keep the physiological systems from completely losing their training adaptations. If the horse has been sedentary, you will have to begin regaining that training base over several months.
The best and most prudent approach is to start at least one or two levels lower than where you think the horse is and monitor the response and recovery time carefully. If the horse recovers within the times specified above, then gradually begin to add more duration to the workouts, again always monitoring the response. If there are any warning signs, back off and give the horse a few days to a week at a much lower level before moving up again.
Other points to consider
Horses kept out on pasture in a group of other horses will be more active and this will help to maintain their fitness level and keep a fairly constant load-bearing force on their legs. If possible, this arrangement is much more desirable than being stall-bound. At the least, try to keep the horse in a paddock if the injury or problem allows.
Keep an eye on the sweat. As the horse gains more aerobic fitness, the sweat will become a more watery consistency with less "foamy" buildup and a more even distribution. The "taste" of the sweat will be less salty and the horse will start to sweat sooner in the workout.
Monitor the feed intake. With any type of layoff, taper off the feed intake, keeping it a balanced ration, since the horse will not need the previous level of energy. As the exercise intensity and duration increases, then adjust the feed ration accordingly. Do not let the horse gain excess weight as this will only cause more problems. Weight should be monitored by use of scales or a weight band.
Understand that it is quite natural for a horse to start feeling good as the fitness level increases. Although he may be a handful, this is not the time to take away his grain ration since his exercise level is increasing. Try to keep the horse outside if possible, where the energy can be burned off before reaching combustion levels. Or try longeing, treadmill work, or pool work before the riding session to take the edge off. Determine if the horse actually needs to be that fit for competition demands. It may not be beneficial to try to keep the fitness level high if the competition does not require it.
Warming down your horse is every bit as important as the warm-up and both are more important following a layoff due to injury. It gives you additional time to ensure that the HR is returning to resting levels and that the training session was not too intense. Include 5 to 10 minutes of light jogging following intense work to remove metabolites from the muscle, followed by suppling and relaxation exercises.
Chronic over-stressing of the horse will result in increased chance of injury, heat, pain, swelling of legs, stiffness and unwillingness to do work, increased resting HR, increased recovery times, sour disposition and off feed. It is particularly important to be aware of any of these signs as the horse is brought back after a layoff
Be aware that various illnesses may still be affecting the body systems even though the horse may not be showing obvious signs. At the Equine Research Centre, we have found that recovery times of horses following a respiratory virus were of much longer duration than the clinical signs. Some were four weeks or even longer. Your veterinarian can advise you on this aspect as extra rest time may be advisable, even after clinical signs have disappeared. It is advisable for your veterinarian to perform a routine blood test before resuming training to assess your horse's health status.
In summary then, keep the horse outside as much as possible, with a group of other horses, and it is less likely that detraining effects will be profound. The injury or problem, of course, must first be solved. If the horse has been purposely laid off to give a break between seasons, then try to fit in two light workouts per week, using a variety of exercise modes. Most important of all, you must monitor the response of the horse to the training. Valuable information can be gained that will allow the horse to be placed back into competition safely and sooner.
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The Equine Research Centre
University of Guelph
Guelph, ON N1G 2W