For the effective realization of a motor task involving muscle action, coordinated attendance of different organic systems is required: mechanical work produced by the muscle contraction is possible thanks to the splitting of the energy sources for muscle stored in the form of high energy phosphates: adenosine triphosphate (ATP). Replacement of these energy sources, over time, is possible thanks to the power of the chemical bonds in the reserves of molecules stored in the muscle itself and others provided by the delivery system mediated by blood transportation, which allows also the Elimination of the waste products from the reactions metabolic intramuscular. The resynthesis of ATP is made from various possible sources: high energy phosphates: Creatina-Fosfato (CP) intramuscular glycogen and intramuscular glucose, lipids and proteins.
The blood circulation is ensured by the function of the heart muscle pump and the passage through vessels of different calibre which distributed selectively, the blood towards the territories metabolically active and restrict it at retail sites demand. This is done by opening and closing controlled arterioles that supply sectors, contracting or dilating the smooth muscle that surrounds them. This control is mediated by local factors such as the temperature and the presence of certain metabolites and neuroendocrine factors.
Cellular biochemical reactions waste products are eliminated in the blood for transport to the emuntorios organs: liver, kidney, intestine, sweat glands.
Many chemical reactions occur in the presence of oxygen, whose provision is secured through the respiratory system, which also contributes to the Elimination of carbon dioxide (CO2) product of intracellular biochemical reactions for the provision of energy. Cell oxygen (VO2) consumption and production (VCO2) carbon dioxide depends on the blood supply or volume min cardiac (VMC), influenced in part by the contents of blood hemoglobin; and the difference arteriovenous oxygen in the territories of metabolically active. Transport and the intracellular utilization of oxygen depend on turn of the intracellular Myoglobin content, the number of mitochondria and the amount of intermediate metabolism enzymes.
Much of the body, approximately 60% in adults, is made up of water, and that is the middle where most of the biochemical reactions occur. The balance of water in the body is regulated through the participation of control mechanisms in the hypothalamus, several components of the endocrine system, kidney, liver, lungs and adrenal glands.
The dynamic equilibrium of the body which could be called "homeocinetica" as opposed to homeostasis or static balance, is ensured through a complex system of regulation of neural short-term and long-term endocrine responses.
Transient "acute" changes, in physiological conditions of the body during physical activity, can be called "answers", as for example the increase in heart rate; on the other hand more permanent changes products of systematic training such as muscle hypertrophy due to overload, are called "adaptations".
All physiological systems are capable of manifesting acute responses to a situation of exercise and chronic adaptations to systematic stimuli repeated, able to surpass a certain threshold. The stimulus of little intensity or some frequent, are not capable of producing adaptations and those of great magnitude of load can cause damage.
These physical stimuli possess certain characteristics in addition to the intensity, such as the total volume of the load, the density or compactes (relationship between load and recovery), and the frequency of application. The cyclic alternation of load dynamics is governed by complex biological laws of adaptation, which is necessary to set the appropriate stimuli and cause desired changes, both populations sports and active people whose primary objective is health. The correct application of these aspects, even though it is based on physiological and methodological principles is not based only on "Science", also constitutes an "art".
"Exercise prescription" correctly and individualized, you learn by studying, but mainly by the experience.