"Oh painful sensation of a muscle that refuses to relax," this is poetry that we may well tell these poor professional footballers in this period of world. What an idea to run as long after a ball like I though it should be an attractive remuneration for such work ... Cramp but also affects the common man, who in fact did not experience this unpleasant feeling of tension during prolonged exercise? At a remarkable paradox cramp, muscle fatigue despite shrinking violently; examine the solution of this problem ... mechanism of muscle contraction.
The force of contraction of a muscle is to be found in the infinitely small, the heart muscle cells, it is here that we find in fact proteins assembled into filaments: the ' constitutes actin thin filaments, and myosin constitutes thick filaments. These filaments bind temporarily slide against each other under the effect of withdrawal of myosin and thus allow the shortening of the muscle cell and thus muscle [see diagram] . Of course the retraction of myosin filaments, requires energy which is in the form of ATP .
1: [ Actin filaments (blue) and myosin (red) slide against each other causing the shortening of the muscle. ]
2: [ Adenosine triphosphate: a molecule used for all biochemical reactions that require energy, it consists of adenine ribose and three phosphate groups ]
Cramp ...
When nerve signal reaches the muscle, the muscle cell mass release of calcium stores it at rest in a sort of tank (sarcoplasmic reticulum). This is the starting signal for contraction, the myosin filaments are then extended to bind to actin filaments, then retracted that causes the shortening.
In an effort to produce muscle ATP quickly, one way to do then is to "ferment" a molecule Glucose is the lactic fermentation . This process is favored for short, intense effort or when the amount of available oxygen is low. But the problem is that this fermentation produces waste, and in particular lactic acid. Now that said acid, said change in pH, that muscle cells do not really. So to avoid this change, the ion currents of the cell will be modified and calcium can then be released into the cell. Neither one, nor two, under the effect of this calcium signal, the filaments of actin and myosin bind, and there is contraction: That's cramp. Note to
passing that these changes in ionic currents may be influenced by various factors such as temperature, diet, or dehydration ...
The solution?
No miracle cure, you just have well prepared her body and especially the effort to stay hydrated in order to promote the elimination of lactic acid on the one hand and ensure the availability of large ions (or minerals) despite sweating on the other. Finally we note that lactic acid is also responsible for muscle soreness, more reason to stay hydrated ...
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