In different sets of experiments 320 school-children and qualified sportsmen (aged from 6 to 32) took part. As an adaptogenic factor a veloergometric exercise of maximal intensity was used.
At the analysis of the examination results it is established that, starting with the age of 6 and finishing with the age of 17, a progressive increase of the body weight (from 25,2± 0,59 kg to 70,1± 0,68 kg) and height (from 126,4 + 0.67 cm до 178,8 ± 0,75 cm) occurs. From 17 to 29 years old the weight-height factors actually remain at the gained level.
The average capacity of the work on the veloergometer, as well as the weight-height factors, achieves its peak level by 17 years old increasing 4, 9 times as much compared to the age of 6, and further on doesn´t undergo any substantial changes. But, if to analyse the relative capacity of the work (per 1 kilo of the body weight), another picture appears. The most progressive growth of the relative capacity is observed in those aged from 6 to 11 (increase by 54%). In the period from 11 to 16 it increases only by 7, 5%; from 16 to 17 - by 6, 2% more; and after 17 years old it remains almost at the same level gradually increasing by 2, 7% to 29 years old.
The relative rate of voluntary tension (RVTr) and maximal force (MFr) progressively increase from 6-year-old age and achieve their maximum to 18 years old. The RVTr and MFr total increment by this age makes 103% and 72% accordingly. From 18 to 28 years old the RVTr didn´t change, and the force gradually increased by 19% more.
If the progressive increase of height-weight factors, contractile characteristics of muscles and physical efficiency are known well enough, then the new-onset age-dependent dynamics of inhibitory-relaxation processes and mechanisms of defence against extreme conditions or factors is unusual and absolutely doesn´t fit in the social image of a growing body´s individual development objective laws.
At the age of 6-11 already a very high muscles´ RVR was registered. Then it gradually decreased and by 14 years old became minimal, having deteriorated by 22, 3%. After 14 the muscles´ RVR started gradually increasing again up to the age of 29, and the early age (6-11) RVR level was achieved only by 20-25.
The age-dependent dynamics of the IRFSD was analogous. Then it progressively decreased (by 12, 6%) achieving its minimal values by 13-15 years old. After 14-15 years old the IRFSD capacity increased and by 23-25 years old took its peak level, and by 29 years old decreased a little.
It is worthy of note that the IRFSD level registered at the age of 6-8 years old was achieved by the age of 20-23 only.
In practice the dynamics of the IRFSD capacity was almost the very spit of the RVR dynamics and inhibitory systems´ functional activity (IFA) of the CNS. The highest IFA level was also registered at the age of 6-7 already. Then the IFA progressively decreased (by 10, 0%) by 14 years old and again grew quickly up to 23 years old and remained at this very level up to 29 years old. The similarity of the dynamics and direct correlation dependencies between the IRFSD, IFA and RVR in all age periods, detected in this experiment, underlines the relevance of the CNS inhibitory systems with relaxation processes of the neuromuscular system and their direct participation in the formation of physiological defence mechanisms, the IRFSD in particular, of the body from extreme conditions or factors once again. The same character of these parameters´ dynamics was observed in women as well, only their decrease at the age of 13-15 was less vividly expressed.
High levels of the IRFSD, IFA, RVR, the activity of inhibitory systems, nervous processes´ balance, performance efficiency and other properties detected in 6-8-year-old children testify that at this very age already the child´s body represents quite a formed (not anatomically, but functionally) living system, possessing all the necessary set of higher integrative, regulatory, adaptative and defence mechanisms to interact effectively both with positive hostility environmental factors, actively resist their stressogenic and damaging actions and struggle for survivability, reproductive property and longevity. It is no coincidence that, according to computations of biologists, the age of human life must be not less than 150 years, and our great compatriot I.I. Mechnikov laid emphasis that a death earlier than 150 years old is not a natural, but a violent one.
Unfortunately, as our research have testified, after the age of 6-8 yeas old a progressive deterioration of all health criteria, achieving the maximum by 14-15 years old, begins. By this age the CNS affectivity increases essentially (Р<0.001); the functional activity of the inhibitory system and the CNS inhibitory control acutely deteriorate (Р<0.001); the IRSD and muscles´ RVR capacity fall (Р<0.001) and a pronounced individual development hypertrophic type forms.
As a result, a healthy child´s body with a quite completely formed mechanisms of adaptation and defence, prepared by the Nature for a long and happy life, for 7-8 school years looses its advantages, adaptive capabilities by 20-30% and becomes defenceless for any kind of harmful effects of the environment.
In this connection a considerable increase of a whole range of negative manifestations of the body life activity in school-children of middle and senior age, marked by many investigators, appears to be quite regular: the metabolism and energy resources consumption increase, the economical and operating efficiency of different organs and systems decreases, the CNS affectability increases and the cerebral cortex inhibitory control weakens, inadequate emotional reactions, neuroses and rapid fatigability emerge, adaptive capabilities of the body decrease, traumatism and case rate increase.
Regular sport activity, judging on the having been analyzed in our research dynamics of sport results growth and functional state of the body, breaks this endless vicious circle, promoting the restoration and perfection of one´s own bodily machinery of urgent adaptation and defence. However, as our long-term experience and the experiments´ results testify, usual sport activity does not suffice to solve this deep problem effectively. The development of a brand new complex system of special physical and functional training, the use of which from the early child age will provide the all-round development and perfection (training) of inhibitory-relaxation processes, one´s own defence mechanisms and formation of the best rational types of long-term adaptation and individual development for an organism.The article is admitted to the International Scientific Conference "Fundamental and applied problems of medicine and biology", United Arab Emirates (Dubai), 15-22th October, 2007, came to the editorial office on 09.11.07.