W. Stronczyński
A. Skrypko
J. Trzeciak
J. Stronczyński. Institute of Sport Games, Laboratory of Computer Science and Statistics. University School of Physical Education, Poznan. Faculty of Physical Culture in Gorzów Wielkopolski

Key words: aerobic endurance, motor abilities, morphological characteristics, efficiency, football players.

Introduction. Proceeding from the observations and analysis of football matches, these athletes are frequently subject to extreme workload, both physical and mental one. Aerobic endurance is an essential element stipulating for success of football players in their sphere [Kubica, 1995; Pac-Pomarnacki, 1997; Bangsbo, Pac-Pomarnacki., 1999; Górski, 2001].

The influence of coordination and conditioning abilities, morphological characteristics and sports experience of football players on the playing efficiency of football players can not be ignored (Stuła, Płaczek,2003; Trzeciak, Chomicz, Tatarczuk, 2006).

Physical endurance is the ability to perform strenuous long-term physical loading involving large muscle groups without major changes in homeostasis and the ability to restore quickly the parameters of the state of repose [Jaskólski, Jaskólska, 2005]. The issue of the influence of motor abilities on defensive and attacking playing efficiency in terms of aerobic endurance has been studied insufficiently.

Motor coordination is defined as the ability to perform complex movements accurately and quickly under dynamic conditions [Starosta, 1993].

The ability to kinesthetic differentiation is determined by the accuracy of movements. Accurate spatiotemporal orientation and forces in the course of motor activity provide for the strong "kinesthetic sense" [Starosta, 2003]. One of the leading coordination abilities is responsiveness, which provides quick performance of integral motor actions. Furthermore, motor accuracy is a result of correct tension and relaxation of the muscle restraining the dynamic body balance [Starosta, Stronczyński, 2010]. Therefore, the ability to maintain balance stipulates for retaining the proper body position. On the other hand, spatiotemporal orientation defines body positions in an exercise, action field and movements of partners, opponents or a ball.

The harmony of movements of football players is determined by the developed motor rhythmic ability [Starosta, Stronczyński, 2010]. Rhythm changes of different rate and pace of movements (steps) are called arrhythmic ability. Arrhythmia of movements showed during various activities with a ball and without it, which is important in this game.

Agility, speed and strength qualities, jumping ability, dexterity and endurance are the basic conditioning skills, stipulating for playing efficiency [Harre, Hauptman, 1988; Southgate, 1993; Gołaszewski, 1998; Sozański, 1999]. The relationship between motor abilities and physical endurance of football players is insufficiently covered in the researches.

Height and body weight should be mentioned as morphological characteristics determining the high level of playing efficiency. As follows from the studies of the best football players of the world, the model height and weight for a football player is 78 kilos and 178 cm respectively [Stronczyński, Stuła, Wasilkiewicz, 2003]. The issue of the relationship between morphological characteristics, sports experience and aerobic endurance of football players is lacking in the available literature.

The playing efficiency in football is difficult to characterize in the objective way, for it is a versatile game and its course is never the same in two games. It presupposes numerous motor, technical, physiological and psychological conditions, being eventually crucial for playing efficiency. Aerobic endurance is an especially important physiological indicator determining efficiency of tactical and technical and motor actions [Raczek, 1980, Pac-Pomarnacki, 1997].

The study of the aerobic endurance with relation to selected motor abilities, morphological characteristics, sports experience and playing efficiency of football players is still extremely relevant.

The purpose of the study was to define the correlation between endurance indicators, motor abilities and morphological characteristics of football players within training classes.

Materials and methods. Football players from the IV and III clubs of the Polish Football League with 11 years of sports experience were the subjects of the study.

Aerobic endurance and morphological characteristics were examined on the faculty of physiology and sports games at the University School of Physical Education Poznań in Gorzów Wielkopolski.

The players had their height and body weight tested. Aerobic efficiency was studied using the treadmill Track master, model 310 AC/R, the level of VO₂max - using the ergometer Oxygon mobile. The subjects were divided into two groups in respect to the levels of VO₂max.

The level of coordination abilities was measured using the following tests:        

- responsiveness (Talaga for Blume, 2006),

- dynamic balance (Talaga for Blume, 2006),

- spatiotemporal orientation (Stronczyński, Maciejewski, 1997)

- comprehensive coordination of a football player (Stronczyński, 2005)

- rhythmization of movements with a ball (Stronczyński, 1997)

- kinesthetic differentiation (Stronczyński 2005).

The conditioning fitness level was defined using some trials from the INKF test: 30 m running from a standing start, vertical jump and "envelope" running (Talaga, 2004).

Hereafter, efficiency of football players was characterized based on the expert supervision in 10 matches. After the last match football players were rated by the 10-point scale in defence and attack.

The analysis of the results.

Speed abilities of a football player are assumed to depend on his speed, which is a derivative of high physical endurance. However, the conclusion on the relationship between speed abilities and VO₂max should not be made based on the obtained results (Tab.1). Thus, the studies of the relationship between physical endurance and power among football players with low VO₂max revealed a high correlation (r =-0.71, p ≤ 0.01). In this case high level of power can make up for the low level of VO₂max, largely stipulated by speed and strength abilities. The low physical endurance is likely to be supplemented by high dexterity in various types of movement with a ball and without it, especially in the case of players with average fitness, as proved by the moderate correlation (r = 0.35).

Table 1. The characteristics of the correlation coefficient between aerobic endurance and conditioning abilities (n = 16)

** statistically significant dependence p ≤ 0.01

he findings presented in Table 1 do not identically confirm the relationship between speed abilities and physical endurance of the subjects. This can only apply to football players with a high level VO₂max. The results confirmed our assumption, that the level of physical endurance at the level of the IV and III Leagues of Poland is one of the many factors stipulating for high efficiency of quick tactical and technical defensive and attacking actions. Concerning football players with lower levels of VO₂max, well developed tactical and technical skills are more crucial for high playing efficiency. The study of the interdependence of the level of speed qualities and VOC₂max of football players of the teams of 1^st and 2^nd League is assumed to have higher connection. This can be applied to power and physical endurance of the subjects. Football players with average sports skills is presumed to be determined by development of strength and speed abilities first but not the level of VO₂max.

The analysis of the results of the relative interdependence between physical endurance and selected coordination abilities (without dividing the subjects into groups with high and low VO₂max) showed a significant correlation in five cases (p>0,05)
(Tab. 2) regarding responsiveness, rate of leg movement, rhythmization and deformity of movements.

Table 2. Numerical characteristics of the Pearson linear correlation coefficients for football players (n = 16).

The results stipulated in Tab. 2 are convergent in both research groups in many cases, except for the correlation between the rate of leg movement and physical endurance showing a more significant divergence. Strenuous leg work during a physical exercise is assumed to be dependent on physical endurance. Thus, football players with so called "quick legs" are better in adapting to a high endurance game while being extremely fatigued.

The data obtained are of major importance in programming a modern sports training for football players. The contents of trainings for development of kinesthetic differentiation, symmetry, rhythmization and rate of movement should be closely related to development of physical endurance. At elite training phases various technical and coordination tasks are to be implemented in conditions of increasing fatigue. Hence, circulatory, respiratory and neuromuscular functions can be improved to obtain the harmony in movements in specific harsh parts of the game.

The analysis of the findings gives grounds for assuming the dependence between some coordination abilities and VO₂max. For example, the nature of the tests of high rate and rhythmization of leg movements was predetermined by their course, which relates to the effect of fatigue on the final result. In these cases the subjects’ physical endurance could be vital. The players with high VO₂max were more likely to show less faults in a game. The reasons can concern strength and flexibility of the nervous system with VO₂max. This can provide the answer regarding the level of the relationship between physical endurance and coordination abilities. The large-scale and more detailed studies of this kind are believed to be very useful for the theory and practice of training of football players in the future.

The statistical analysis failed to reveal any significant relationship between height and VO₂max (Tabl. 3). Based on the practical experience we can admit that football players with different height have similar levels of physical endurance. Greater, but inversely proportional, interdependences were detected in respect to body weight, indicating to greater endurance of players with lower weight at sport competitions.

Table 3. The correlation coefficient between aerobic endurance and morphological characteristics and sports experience (n = 16)

The level of VO₂max was proved to be correlated with the number of years of sports experience in football (r=0.44). This result was expected, for, as proved in the theory and practice, aerobic endurance of experienced athletes is known to be on a higher level.

The findings on the influence of physical endurance at the level of playing efficiency in most cases indicate to the correlation between the studied indicators. High level of VO₂max is a determinant of playing efficiency in attack (r = 0,49, p>0,5).

The results for players with high and low VO₂max in terms of their playing efficiency were significantly similar. But one should pay attention to some other efficiency determinants.

The studies on the influence of physical endurance on the level of motor abilities and playing efficiency of football players are always interesting for a number of reasons. As proved by the theory and practice, tactical and technical efficiency during a match is caused by the high level of physical endurance to a larger extent. Player’s actions in the situation of increasing fatigue due to running various distances at alternating paces and struggling directly with an opponent are subject mainly to endurance level and mental stability. Both of the components provide the high level of special endurance. The resistance to fatigue and external loadings combined with motivation can stipulate for success, as it often occurs at the final phases of the match.

Hence, the studies of the influence of endurance indicators on playing efficiency from the psychological point of view can provide new information on the actions of football players with different levels of Vo2max in a match.

The studies of the body constitution of football players of European Premier Leagues testified to the advantage of leptosomic types over athletic and pyknic ones. In this aspect tall players with a relatively smaller body weight can be more preferable.

Table 4. The correlation between aerobic endurance and playing efficiency of football players (n = 16)

* statistically significant dependence p ≤ 0.01

Conclusions   

1. Coordination abilities such as responsiveness, high rate of leg movement, kinesthetic differentiation and motor rhythmization were proved to relate to the level of physical endurance.

2. The statistical test results failed to reveal any statistically significant dependence of physical endurance and conditional abilities.

3. VO₂max and body weight and sports experience of football players are correlated.

4. The research results revealed the effect of endurance indicators on playing efficiency, but speed and strength abilities are also essential.

5. The obtained results prove the necessity of further researches on the quoted problem with larger groups of subjects of different age and sports skills.

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Author’s contacts: dskrip4@mail.ru