What is fatigue?

Fatigue muscles in their operation is one of the most common things that are familiar to everyone. Even more amazing is that only relatively recently begun to shape the way to understanding the nature of fatigue. Previously, scientists thought that the causes of fatigue are accumulating in the muscle metabolites, in particular lactic acid. So far, such views can often be found in books.
Meanwhile, back at the end of the last century wonderful Italian physiologist Angelo moss drew attention to the role of the status of the nervous system in the development of muscle fatigue person. He designed the device - aragraph (from the Greek. ergon - work, grapho - writing) - allowed to study the work of muscles, bending the wrist. A particularly important role played research I. M. Sechenov, who in 1903 experiences deeply justified the idea that during muscular work tire first of all, not muscle, and much more brittle and easier exhaustible nerve centers. In the near future of Soviet research this view was confirmed and developed. Many psychologists who study the problem of fatigue, including the author of this book, believe now, that would be the right thing tired link neuromuscular apparatus to see in the higher parts of the Central nervous system, namely in the cortical centers. It cortical cells, growing weary primarily responsible for the decline in the health of muscles.
Of course, at first glance it seems very strange, as it can be considered that tired primarily the brain, and not muscles, while fatigue is something we feel a muscle!
During neurosurgical operations pain is only made when the skin incision, trepanation of the skull and the opening of the meninges. Manipulation of brain tissue pain relief does not require, and it is very important for the surgeon may, talking with patients to control their actions. If the patient stops responding to questions, loses consciousness, the surgeon clear that it touched the vital center of the brain; the bug instantly corrected. During such operations, irritating tassel a specific area of the cortex of the brain, ask the patient what he feels. If you touch the occipital region, where are the visual centers, the patient may answer "my eyes sparks showered". If irritation parietal region associated with skin sensitivity, the patient might say, "You tickle me heel" or "You pinched my neck". In other words, the person feels the touch not the brain, and to the part of the body, responsible for this item of the brain. It is therefore not surprising that when fatigue nervous center, Manager of the biceps shoulder, we feel the fatigue in the muscles, but not in the head. "The source of the sensation of fatigue, wrote I. M. Sechenov, is commonly placed in the working muscles; I put it... only in the Central nervous system".
Experiments confirm the leading role of the higher departments of a brain in fatigue with muscle man. For example, with complete exhaustion, when the person is no longer able to produce a certain movement, irritation of electric shock the muscles causes still quite strong reduction. So, muscle could still work, but the brain is not able to manage it.

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