To train correctly with a horse and to prevent injuries, it is useful if you know something about anatomy and biomechanics. The functioning of the muscles, for example. I always like to listen to exercise physiologist Dr. Eric van Breda, who can talk endlessly about that. About 45 to 55 percent of a horse’s body is made up of muscles. Because muscle cells can contract and relax again, they ensure movement. Some are controlled consciously, others – like the heart – all by themselves. There are many misunderstandings about muscles. To name one: a horse can never gain more muscles. How many muscle cells a horse has is hereditary. You can’t change that, no matter how much you practice. Muscles can become thicker through training. If you train a horse, all kinds of substances in those muscle cells are used up and some damage occurs, in the form of cracks in proteins. That’s okay, it’s a natural process. It is actually the intention of training. It is an incentive for the muscle cells to build in some extras during recovery, so that next time they are prepared for the requested effort. This extra reserve makes the muscles thicker, making it look like a horse has gained more muscles.
Fuel
Muscles need fuel, but also materials to repair the damage after an effort. Carbohydrates and fats provide energy. Proteins are the building blocks for recovery. Many riders think that proteins are bad for a horse. That’s not right, they are needed. But don’t stuff a horse with proteins, carbohydrates and fats, because you want more muscle building. It is a matter of a correct amount of feed, in combination with training. Horses become fat from too much feed with not enough labor, which is unhealthy. Most dressage, jumping and recreational horses perform well on a basic ration of a lot of roughage and a little hard feed. Only with more extreme exertion, for example for endurance or eventing, it is wise to investigate, perhaps with expert help, whether the diet should be supplemented.
Warning: know how
Dr. Eric van Breda warns that the diet can also have a negative effect on muscles. Take the time of feeding, for example. Some riders feed a horse just before an effort. This is not wise, because the processing of a meal causes fluctuations in glucose and insulin levels, which can make a horse feel tired or somewhat uncoordinated. It is also not necessary, because if a horse has been trained more often, there is a store of energy in a muscle cell. Incidentally, you can give roughage, because it digests so slowly that it does not cause fluctuations. If you are going to do something exciting with a horse, it is good to give some roughage, because chewing has a stress-reducing effect. This is because it produces saliva. This lowers the acidity of the stomach and gives a horse a pleasant feeling.
Endurance or exertion
Training not only stimulates muscle cells to make more reserves. Converting fuel in the cells into energy also becomes increasingly efficient. No matter how well you exercise, horses have a predisposition to the type of muscle cells they naturally have. They are born with that. You have the red ones, which give more endurance. White muscle fibers are suitable for short power bursts. Arabs, for example, have more red muscle fibers and are therefore suitable for endurance. Horses also have a small amount of mixed muscle cells, which through specific training become suitable for endurance or exertion. This is reversible, but it takes time. If you have done a lot of endurance training, the mixed muscles are focused on endurance and less on explosive power. You can change this by changing the training. But that will take a few weeks.
When muscles are not used, they do not disappear, but they do become thinner. Anyone who has ever had an arm or a leg in a cast can relate to this. Unused muscles go to a minimum level at which they just survive. This also happens when a nerve is blocked, for example by an ill-fitting saddle. Only in very severe malnutrition does the body break down muscles to use the proteins as fuel for the brain.
Muscle pain occurs when muscle cells are damaged by training. People often talk about “ruptured muscle cells”, but it is usually not that bad. Only when you have really gone too far muscle cells can tear, which is immediately very dangerous for a horse. This releases the content that contains myoglobin. That is poisonous for the kidneys. If this happens, the urine has a brown color. If you see that, your horse has a big problem and you should immediately call the vet. But then you must have done something very foolish trainingwise, because a horse can naturally cope with a lot. Much more than a human.
Tying up
Brown urine also occurs with Monday morning disease or azoturia. This is a form of tying up, in which cells are damaged. But the cause is different. It arises when a horse that is trained a lot and therefore receives energy-rich (power) food, is suddenly on rest for a day. If the amount of food is not drastically reduced, he will get an overdose of fuel, causing the muscle cells to explode, as it were. A horse with this problem can hardly walk from pain from one moment to the next. And you shouldn’t ask that of him. Call the vet right away! It’s called “Monday morning disease ” because it used to happen when workhorses had rest on Sunday and still were fed the usual amount. The moral of the story is of course that you have to adjust the diet to the energy consumption.