By fatigue we mean the diminution of the functional power of an organ, or of the whole organism, due to an excess of work.
The fatigue threshold represents the demarcation limit between complete efficiency and the beginning of the decline in functional power.
The training through multiple activities aims to achieve an improvement in performance and to remove the moment of the onset of fatigue.
In practice, training manifests itself as a systematic and rational repetition of certain movements and behaviors with the aim of obtaining a performance improvement.
The structural and functional changes that occur in our body because of training, have a close relationship with the type of motor performance that has caused them: every form of movement corresponds to a type of adaptation.
In practice it happens that in the phases immediately following the physical effort, the organic and muscular structures urged to produce and support it, are not limited to overcoming the fatigue situation with a return to normal conditions, but have a reconstructive reaction that leads them to overcome the situation before stimulation.
These moments of supercompensation have a limited duration and progressively returns to the normal situation.
It is necessary to provoke other situations of supercompensation before the previous ones are completely exhausted, that is to say a “summation of the training action”(Matwejew, 1972).
The repetition of these stressful situations will cause the gradual adjustment of athletic abilities, putting the body in a position to overcome workloads with less accumulation of fatigue, or to express higher and higher performances. Supercompensation should not be understood from a physiological point of view but only as an improvement in the accumulation of glycogen.
The larger the glucose stores (glycogen stores) in the soccer's muscle, later he will feel tired and the longer he will maintain the ability to do a very high intensity job
(Cogan Coyle, 1989).
The basic element of soccer performance in terms of energy use and consumption is the running action.
The specialists were concerned to detect “what” runs the amateur soccer player during a match; in general it has been verified that this run amounts to about 8,000 meters. This would not even represent a mid-level athletic performance, if referring exclusively to the total competition time (90’).
A careful analysis of the workload, shows that within this distance are carried out:
- sprints;
- arrests and braking;
- changes of direction;
- ball controls;
- contrasts with opponents.
In other words, the soccer game is a succession of different performance for intensity type according to the game’s development and occurs within a specified period of time. Any combination of soccer performance with those of other disciplines (e.g. athletics) is really arbitrary and wrong. The soccer player from an athletic point of view is to be considered just a player and that's it. The 8,000 meters of the player's run are divided as follows:
- walk about 20% (~1.600 meters);
- slow running about 35% (~2.800 meters);
- reaches 25% (~2.000 meters);
- sprint 15% (~1.200 meters);
- backwards running about 5% (~400 meters);
Midfielders usually run higher distances than defenders and forwards. The amounts of running and the type of gait vary a lot from role to role and in the role itself in relation to the physical-athletic characteristics and above all the player's characteristics.
The distances run at maximum speed vary from 3/4 meters up to 25/30 meters, the most frequent are 10/15 meters and are repeated 50/60 times.
I also find it interesting to present the results of a study on heart rates expressed by players during a competition. The recorded values show that the player is not subject to very high tensions.
For each half of a game the following pulsating frequencies were detected:
| Pulsations per minute | offensives | Midfielders and lateral defenders | Central defender |
| 126/131 | 11’45’’ | 2’45’’ | 29’00’’ |
| 132/155 | 9’45’’ | 5’15’’ | 29’00’’ |
| 156/173 | 12’00’’ | 27’30’’ | 16’00’’ |
| 174/185 | 9’00’’ | 8’45’’ | 0’00’’ |
| 186/204 | 2’30’’ | 0’45’’ | 0’00’’ |
These figures lead to some general considerations:
1 there are significant differences between the average performance of the various players;
2 with the exception of the central defender all the other players are subjected to a wide range of stimuli;
3 in the defenders and midfielders the period of average intensity prevails while for the forwards we have the longest period of minimum intensity, but also the longest of maximum intensity.
Let us now try to analyze how movement and training can produce changes in our body. For convenience I will describe separately the effects of the movement produced on the muscles, on the joints, on the bones, on the internal organs, on the mind and also on the relationships with others, but it is necessary to keep in mind that often these effects occur simultaneously.
EFFECTS ON MUSCLES
Muscles are the active organs of movement, in fact they are made up of fibers that contract in the presence of impulses (nervous commands).The movement produces the following transformations on the muscle:
1 increase in volume: the muscle, if made to work intensely to lift weights or to overcome a resistance, becomes bigger and at the same time increases its force.
2 increase in length: the muscle maintains or increases its length by means of continuous work to which it is subjected, the muscle lengthening allows to fully exploit the joint width.
3 increased capillaries: the muscle, engaged in a work of mild intensity, but of long duration, increases its capillarization that is the number of channels that bring the oxygen (brought from the blood) to the muscle fibers. This results in an improved ability to supply the oxygen muscle: a condition that allows the muscle to resist fatigue for longer.
4 increase of energy substances: the movement allows the increase of energy substances (glycogen) necessary for muscle contraction.
5 improving the transmission of nerve stimuli: training makes the transmission of nerve stimuli from the brain to the muscles faster and more precise, thus improving the speed and coordination of movements.
EFFECTS ON JOINTS
The joints constitute the “junction” system of our body. They allow the movement of the various body segments. The articulation consists of the union of two bones whose ends are called articular heads. The movement produces the following transformations on the joints:
1 maintenance of physiological mobility: the articulation to maintain its normal mobility must be used to the maximum of its possibilities of movement.
2 increase and recovery of mobility: to recover lost mobility and increase that possessed, it is necessary to use particular forms of training and movement.
3 strengthening of the articular capsules: the joint capsule, made up of ligaments and muscles, has the task of keeping the articular heads