The match is an irregular interval load
The
football match is an open skills-based sport activity of acycled intervals.
Open skills mean that the movement of the player is determined by the movement
of the opponents and teammates. The acycled intervals are created by irregular
distances and directions of various speed. These intervals may change by the
game of the team, both as distances and intensity concerned. The average of the
movement speed of an adult player is 6-7 km/h in 90 minutes. This movement intensity
is equal to the speed of a faster walk. I must refer to an earlier article on
analysis of matches, it can be observed well also here, that the football
player performs more than half of the match with low intensity even in the
highest leagues.
Each
and every impact requires increased energy investment from the system due to
the changing speed of movement and intensity of movement. The movement of the
player is most similar to car driving. A car „consumes“ much more fuels during
city transport, where it starts, stops, accelerates and slows down. Just like
in a football match. 10-12 km
of straightforward line running at a balanced speed and 10-12 km of movement
performance, made up of 8-10 m
sections with many changes of directions and speed cannot be compared. There is
a significant difference between the two types of practices, investigating both
the physiological effect and the coordination work.
The
speed of movement of the football player changes dynamically. The high-speed
work of several seconds is followed by a shorter-longer performance of moderate
intensity. The proportion of the fast and slow work performance within the
sections is one of the most important parts of the physical capacity. If the
period of 45-55 minutes spent with active movement is broken down to 1,000 meters , running
of 1,000 meter
would take 4 minutes and 10-30 seconds. The distribution of load of this kind
is not precise, because the athlete performs the active movement in 90 minutes
in intervals of irregular speed. High intensity work, repeated at least once a
minute, significantly determines the performance of work.
If the
player can „gain strength“ quickly, his „condition is good“. Frequent repeat of
the dynamic sections (figure 1) highly influences every movement performance.
Characteristics of complex movements are changing direction, speed and force.
Figure 1. GPSport.
Papp 2011.
Due to
the acyclic character of the football movement, the speed of movement and the
related load cannot be evaluated with the cyclic-like running movement. The
frequent changes of direction and speed occurring during the short intervals
cause increased effort to a the musculature. This is why the value of cardiac
frequency per minute is 130-140 during a straight line running of 10 km/h , while if the
athlete turns or changes direction several times during the running at a speed
of 10 km/h ,
the former value increases to 150-160. The stops and slowdowns - depending on
the direction of the movement -, require even by one and a half-twice as much
efforts from the football player than the accelerations. Their total effect
improves the rate of the effort along with the load on the circular system.
Plenty
of efforts affect the player in several seconds, but their duration is really
short.
The
movement of a player can be followed in the following graphic (figure 2) in an
interval of 5 seconds. The rate of the forces (g) appearing during the complex
movement is shown by three lines. The negative values show the rate of the
force performed during a slowdown on the graphic. It can be observed well, that
the player performs a bigger force during the up and down movement (red line) during
acceleration, while during the side movements (green line), he must use the biggest force to stop.
There is a similar effect in case of the back and forth movements (yellow line) as well. The
football player must use more strength to stop or slow down while his body is
in swing. In a match situation, the success of football-specific speed is
determined rather by the speed of stop-slowdown than the skill of acceleration.
The
volume of the forces (g) appearing during the movement changes depending on
intensity of the movement. - g shows the volume of the force exercised during
the slowdown and stop, while +g shows the volume of the force during
acceleration. The complex stimuli affect the player in a quick and complex
form, the reactions to the stimuli appearing in a millisecond are involuntary,
however they cause contraction and muscle tension. The stimuli reach the
musculature- and nervous system so quickly that they cannot be reacted to
consciously. To the „training of reactions like this“ one of the most effective
forms of training is the so-called reactive or plyometric force training. The
effect mechanisms of „slowdown“ of movement (anisometric excentric), „stopping
and keeping“ of the athlete (isometric) and „acceleration“ of the athlete
(anisometric concentric) can be modelled here well. The relation of the
nervous- and musculature system and the movement coordination level
significantly influence success. Even 15-25 complex stimuli may affect the
musculature in 5 seconds, arriving from several directions and it uses the
speed of the contraction and relaxation of the muscle at a high level.
Figure 2. GPSports Systems, Papp 2012.
The
significant efforts during the complex movements increase the rate of load on
the system. It is shown in the reaction of the circulatory system. While a
uniformly straightforward movement leads to moderate cardiovascular reaction, a
movement of short intervals at the same speed increases the cardiac frequency
better.
Table 3. (Bloomfield 2007) Summary of a survey. Number of turns and changes of
directions has been broken
down to positions. It can be seen well, that defenders or forwards perform the
most turns and changes of directions. It may play a more important role in
training of football players, if a certain type of training, broken down to
positions, is applied. In case of players moving the most right around the
gate, the distances are shorter, but they include more changes of directions
than in case of left and right defenders. The movements of the players on the
left and right of the field are longer, thus the physical load is nearly the
same, however with different characteristics.
The
differentiated training is the basis of maximal improvement of performance. By
the following table we can determine, how much the players should exercise of
each given type of movements. The earlier articles discussed the physiological
effects, now the character of movement will be put in focus. The practices must
be different from one another both in technique and load on the circulatory system
and the musculature. In certain sections of weekly exercises, it is practical
to have the players performed different workouts in accordance with their
positions. This way also the performance of the football player is improved
better during a match.
It
can be observed in the abovementioned published table, that players playing in
center of the midfield run more than their team mates footballing in the middle
of the defense area. But it cannot be considered as their load is bigger than
those of the middle defenders. The defenders - on the basis of the measurement
of Bloomfield
Table 3.
Turns
|
Forward
|
Midfielder
|
Defender
|
¼ turn
|
625
|
495
|
647
|
½ turn
|
94
|
96
|
92
|
¾ turn
|
5
|
8
|
4
|
Complete turn
|
7
|
9
|
0
|
Complex change of direction
|
20
|
10
|
17
|
Total changes of direction
|
748
|
608
|
822
|
Barros et al. (2007) compared
the movement intensities of the players in the Brazilian championship (table
4). The movements performed in various speed domains were significantly
different. The performances of 55 players were summarized and they were
analyzed from speed of a walk to the zone of sprint runs. However Bloomfield and Barros investigated
teams of different football cultures, the various physical profile of the
positions was common in every survey. Those players were especially different
from the average of the team, who play directly in front of the gate. Despite
the shorter quantity of movements, the shorter distances include more turns and
parallel to this more stops and starts. Therefore the physical activity of
these football players is similarly high as that of their mates, who run more.
The playing activity, reducing to a smaller area assumes an increased muscle work
and anaerobic win of energy.
Table 4.
Position
|
0 -
|
11-
|
14-
|
19-
|
>
|
Total
movements
|
||||||
Half-time
1
|
Half-time
2
|
Half-time
1
|
Half-time
2
|
Half-time
1
|
Half-time
2
|
Half-time
1
|
Half-time
2
|
Half-time
1
|
Half-time
2
|
|||
Centre
back
|
705
m
|
|||||||||||
Left or
| ||||||||||||
