Comparative characteristics of anthropometric indicators, level of physical and technical readiness of young players of 12 and 15 years of different playing fields

Purpose: To develop model characteristics of physical and technical fitness of players of 12 and 15 years of different playing roles.Material and methods. The study was attended by football players of 12 and 15 years of sport school "Areal" Kharkiv, in which the developed technologies were applied in the educational process. In total, 23 forvards, 28 midfielders, 30 defenders and 15 goalkeepers were invited for the survey. Indicators of the running time of segments of 15 m from the course, 30 m from the course and 60 m from the course were determined; shuttle running time 5 to 20 m. Determined the length and weight of the body; Heart rate at rest and heart rate after a shuttle run. From the technical readiness indicators were determined: the time of holding the soccer ball on the foot; juggling, that is, the number of shots of the ball with the foot without losing the ball; time to run a soccer ball on a mission; goal kicks for accuracy; strikes the ball at flight range.Results. Young players of 12 and 15 years of different game specializations differ in terms of physical and technical fitness. The largest number of significant differences were found in the technical readiness of football players for 15 years. Field players at speed capabilities are significantly superior to goalkeepers. Goalkeepers, on the contrary, have lower running speeds. The level of speed endurance is relatively high for defenders and midfielders, as opposed to goalkeepers. The obtained data allowed us to build models of physical development, physical and technical readiness of players of 12 and 15 years of different playing fields, on the basis of which training programs for representatives of different playing roles can be developed.Conclusions. The data obtained indicate the need for a differentiated approach in the training process of young football players, taking into account their playing role. The differentiated approach is more relevant at the age of 15 compared to the age of 12.


Introduction
The problem of training young football players is becoming more urgent nowadays [1,2,3]. Effective functioning of the system of sports reserve, improving the quality of training and training process for young athletes can be ensured only with rigorous scientific substantiation of both the system as a whole and its individual components [4,5,6]. Optimal design of the training process technology, the formation of training programs, the selection of adequate training methods and methods of purposeful recovery and purposeful recovery is possible only on the basis of the laws of age-related development of information on the functional features of athletes [7,8,9].
In the literature, aspects of this problem are fragmented [10,11,12] and mainly concern skilled adult football players. At the same time, special attention should be paid to managing the development of adaptation, functional readiness, optimization of the training process of young footballers at the stage of advanced specialization. This is due to the fact that this stage of long-term sports training coincides with powerful ontogenetic processes, the beginning of the manifestation of individual features of the mechanisms of regulation of functions and adaptation processes, on the basis of which, in particular, the game specialization of young football players is determined [13,14,15].
Improving the efficiency of the training process is associated with the development and implementation of various means and methods of training athletes. One of the most effective approaches to optimize the training process, taking into account trends in the development of a particular sport, is the use of readiness indicators that allow you to individualize the training process [1].
But there is practically no information in the literary data regarding the model characteristics of the readiness of players of 12 and 15 years of different playing fields. The future of sports, including football, in the individualization of the training process [4,5]. Football is also a unique feature of combining in one team as players with different anthropometric and functional indicators. Of course, the construction of the training process is greatly complicated by the need to study and apply an individual approach to each player of the team, but it is a basic requirement of modern sports.
Individual approach is needed not only for players of different roles, but also for players of the same game functions. Modern scientific methods allow to give an accurate description of the individual characteristics of athletes and to build "ideal" models of athletes. However, such methods are rarely used, from which the effectiveness of the training process is significantly reduced.
Individual approach to the players is necessary at all stages of sports training, includingat 12 and 15 years, since in these age groups there is a qualitative leap in the level of physical development, which is reflected in the indicators of physical and technical fitness [16,17,18]. In basketball, during this period there is a more rigorous distribution of athletes in terms of functions (which are not always clearly defined in athletes at this stage of preparation), their individual playing profile is determined, and therefore this period plays an important role in becoming a high-class athlete [19,20,21]. That is why the pressing issue is to determine the features of physical development, physical and technical preparedness of players of different game roles in these age groups.
Based on the above, this study hypothesized that at the age of 12 years there can already be significant differences in the indicators of physical development, physical and technical fitness, which become more significant at the age of 15 years.
The purpose of the study is to develop model characteristics of physical and technical fitness of players of 12 and 15 years of different playing fields.

Participants
The study was attended by football players of 12 and 15 years of school "Areal" Kharkiv, in which the developed technologies were applied in the educational process. A total of 23 forwards (12 players 12 years and 11 players 15 years), 28 midfielders (14 players 12 years and 14 players 15 years), 30 (15 players 12 years and 15 players 15 years), defenders and 15 goalkeepers were invited for the survey (8 players 12 years and 7 players 15 years).

Experimental protocol
To achieve this goal, a comprehensive testing of physical performance and basic indicators of functional fitness in young players of 12 and 15 years of different playing roles was carried out. In the course of the researches the indicators of speed qualities were determined by the time of running of segments of 15 m from the course, 30 m from the course and 60 m from the course (the test participant makes a run up to 10 meters, at the maximum speed crosses the starting line and overcomes the distance of 15 meters, 30 m, 60 m); high speed endurance (shuttle running time 5 to 20 m). 46 Health, sport, rehabilitation Здоров'я, спорт, реабілітація Здоровье, спорт, реабилитация 02 From indicators of physical development the length and weight of the body were determined; from indicators of functional readiness -resting heart rate and heart rate after shuttle running.
From the indicators of technical readiness determined the following: -time to hold the soccer ball on the foot: the test participant locks the ball on the foot and holds it for as long as possible. It is impossible to stuff and jump on a support leg; -juggling, that is, the number of shots of the ball with the foot without losing the ball; -the time of running a soccer ball on a mission. There is a ball on the line. From the line there are three skittles, a distance of 3 m, 6 m, 9.5 m. According to the examiner's whistle, the test participant runs the skittles "snake" on the right side; -shots on goal for accuracy of hit. The gates are divided into 6 equal squares. We set the ball at 11m. The task of the test participant is to get the ball into these squares, at the bottom -at most one touch of the ball to the ground, three balls per square. Number of hits -18. One hit -1 point.
-Ball strikes on flight range. Set the ball on the line. The test taker's job is to hit the ball as far as possible. The result is recorded at the first touch of the ball to the ground.

Statistical analysis
In the mathematical processing of primary materials of this study, in addition to the calculation of primary statistics, a comparative analysis of the averages by t -Student's t test was conducted. Indicators were processed using modern computer programs -EXEL and SPSS.

Results
Comparing the indicators of physical development (length and body weight) (Tables 1, 2), it can be seen that according to these parameters the players of different game roles practically do not differ from each other (p>0.05). This provision applies to both 12-year-olds and 15-year-olds. The average length of goalkeepers 12 years is 157.67 cm, of defenders 12 years is 152.0 cm, of midfielders 12 years is 155.6 cm, of forwards 12 years is 155. 6 [1], who found that goalkeepers have the greatest weight and body length. These differences with the results of other authors can be explained by the low football experience of the surveyed children and the need to improve the system of distribution of players by function.
Regarding the indicators of functional readiness, it can be noted that in terms of heart rate, the representatives of different game roles, both 12 and 15 years, do not have significant differences (Tables 1, 2). But it should be noted that there is a tendency to the lowest values of resting heart rate at goalkeepers and increasing resting heart rate at defenders, midfielders and the greatest values of resting heart at attackers.
The obtained data can be explained by the greater emotional endurance of the goalkeepers and the least by the attackers, which affects the resting heart rate. This trend is more pronounced in football players 15 years old compared to football players 12 years old. The average resting heart rate at goalkeepers 12 years is 76 beats·min -1 , for defenders 12 years is 76.5 beats·min -1 , for midfielders 12 years is 79.6 beats·min -1 , for forwards 12 years is 82.8 beats·min -1 . The average resting heart rate at goalkeepers 15 years is 68 beats·min -1 , at defenders 15 years is 72 beats·min -1 , at midfielders 15 years is 70.8 beats·min -1 , at forwards 15 years is 75.6 beats·min -1 .
A similar trend is observed in 15 meters running. Forwards, defenders and midfielders are better than goalkeepers. So, the average value of running for 15 m at goalkeepers 12 years is 5.06 s, for defenders 12 years is 4.73 s, for midfielders 12 years is 4.77 s, for forwards 12 years is 27.44 s. The average running distance of 15 m for goalkeepers of 15 years is 4.67 seconds, for defenders of 15 years is 3.97 s, for midfielders 15 years is 3.4 s, for forwards 15 years is 3.57 s (Tab. 1, 2) .
A similar trend is observed in 30 meters running. Forwards, defenders and midfielders, these indicators are better than goalkeepers. Thus, the average values of running for 30 m at goalkeepers 12 years is 6.79 s, for defenders 12 years is 6.49 s, midfielders 12 years is 6.53 s, forwards 12 years is 6.55 s. The average running distance of 30 m for goalkeepers 15 years is 5.93 s, for defenders 15 years is 5.48 s, for midfielders 15 years is 5.4 s, for forwards 15 years is 5.78 s. Differences between goalkeepers and forwards 15 years, goalkeepers and midfielders 15 years, goalkeepers and defenders 15 years are significant at p<0,05 (Tab. 1, 2).
The detected pattern is also observed in the indicators of running at 60 m. Forwards, defenders and midfielders, these indicators are better than for goalkeepers. Thus, the average values of running at 60 m for goalkeepers 12 years is 9.85 s, for defenders 12 years is 9.66 s, for midfielders 12 years is 9.62 s, for forwards 12 years is 9.55 s. The average running distance of 60 m for goalkeepers 15 years is 8.64 s, for defenders 15 years is 8.27 s, for midfielders 15 years is 8.12 s, for forwards 15 years is 8.16 s. Differences between goalkeepers and forwards 15 years, goalkeepers and midfielders 15 years, goalkeepers and defenders 15 years are significant at p<0,05 (Tab. 1, 2).
The biggest differences between the representatives of different game roles are found in the technical readiness, especially concerning the indicators of juggling, keeping the ball on the foot, accuracy of the range of strikes. The average goal time of a goalkeeper 12 years is 13.63 s, for defenders 12 years is 13.01 s, for midfielders 12 years is 13.88 s, for forwards 12 years is 13.78 s. Goalkeepers of 15 years have a median time at 9.77 s, defenders -at 9.8 s, midfielders -at 9.81 s, forwards -at 9.06 s. Differences between goalkeepers and forwards 15 years are significant at p <0.05 (Tab. 1, 2). The average values of the accuracy of shots of the ball on goal at goalkeepers 12 years make 6,6 points, at defenders 12 years make 5 points, at midfielders 12 years make 6,6 points, at forwards 12 years make 7 points. The average values of the accuracy of shots of the ball on goal at goalkeepers 15 years make 6,6 points, at defenders 15 years make 9 points, at midfielders 15 years make 10,3 points, at forwards make 15 years 10,75 points. Differences between goalkeepers and forwards 15 years are significant at p<0.05 (Tab.1, 2).
The average value of the ball strikes at goalkeepers 12 years is 27 m, at defenders 12 years is 25.5 m, at midfielders 12 years is 23.2 m, at forwards 12 years is 21.6 m, at goalkeepers 15 years is 48.3 m, at defenders 15 years is 41.25 m, at midfielders 15 years is 37 m, at forwards 15 years is 35.6 m. Forwards and midfielders for 15 years are significant at p<0.05 (Tab.1, 2).
Thus, the field players at speed capabilities are significantly superior to goalkeepers. Goalkeepers, by contrast, have lower running speeds (Fig. 1).
The level of speed endurance is relatively high for defenders and midfielders, as opposed to goalkeepers. The obtained data allowed us to build models of physical development, physical and technical readiness of players of 12 and 15 years of different game roles, on the basis of which training programs for representatives of different game roles can be developed (Fig. 1). 51 Health, sport, rehabilitation Здоров'я, спорт, реабілітація Здоровье, спорт, реабилитация

Discussion
The study confirmed the hypothesis of the presence of significant differences in the indicators of physical development, the level of physical and technical readiness of young players of different playing fields. These discrepancies are already observed at the age of 12 years and are exacerbated at the age of 15 years. The data obtained indicate the need for a differentiated approach to the training of young players of age groups.
As is well known, modern youth football develops by increasing the requirements to all sides of the training of young athletes [1,6,7]. In the process of competitive activity on the body are significant in magnitude and duration of loading, requiring the maximum mobilization of the body of young athletes and make high demands on their readiness. Therefore, for the proper construction of the training process, it is necessary to identify the features of the physical and technical readiness of the players of different game roles [9,17].
The results of our study complement the results of the authors [1,19] who believe that in the preparation of football players of this age the coach should take into account their morpho-functional capabilities [4,6]. Comparing the indicators of physical development of football players, it can be seen that in these parameters the players of different playing roles are practically no different from each other. The findings differ somewhat from the results of studies by other authors [21], who found that goalkeepers have the greatest weight and body length. These differences with the results of other authors can be explained by the low football experience of the surveyed children and the need to improve the system of distribution of players by function.
In football, as in other sports games, each game position poses certain requirements to the level of manifestation of different qualities and properties of athletes, which must be taken into account in their evaluation [4,5]. Therefore, in our study, we compared players of different game roles with each other. Goalkeepers have been found to have virtually low technical and physical fitness scores in virtually all testing results, as opposed to hitters, defenders, and midfielders. We explain this by the fact that the goalkeeper is a highly specialized player of defense and trains on a separate program. As a result of comparing most indicators of physical and technical preparedness of the strikers, defenders and Health, sport, rehabilitation Здоров'я, спорт, реабілітація Здоровье, спорт, реабилитация 02 midfielders, no significant differences were found. This is due to the fact that in the training process the coach often changes the playing role of young athletes, in order to train and find the optimal playing role of each football player, depending on the competitive period. After all, the main feature of adolescence is associated with the process of puberty, resulting in significant changes in the psyche, there is high emotionality, mood imbalance, inflammation, exaggeration of their capabilities. Very often the manifestation of the so-called sense of adulthood is reflected in the behavior of the players in the game. At the same time, the body of adolescents is quickly adjusted to work and easily readjusted to another type of activity, due to the great mobility of nervous processes [19]. Therefore, in the practical work of the coach actively put players of 12 and 15 years in different zones of the playing field, thereby teaching them the specifics of different playing roles.
Thus, when choosing training loads for goalkeepers, trainers need to take into account the data obtained, which will allow to develop optimal programs for the development of flexibility, speed, strength, agility, as well as for improving technical skill. When selecting funds in the training process of representatives of other game roles, it is necessary to pay special attention to the implementation of the techniques of football players 12 and 15 years.

Conclusions
1. Young players of 12 and 15 years of different game specializations differ in terms of physical and technical fitness. The largest number of significant differences were found in the technical readiness of football players for 15 years.
2. Field players at speed capabilities are significantly superior to goalkeepers. Goalkeepers, on the contrary, have lower running speeds. The level of speed endurance is relatively high for defenders and midfielders, as opposed to goalkeepers. The obtained data allowed us to build models of physical development, physical and technical readiness of players of 12 and 15 years of different playing fields, on the basis of which training programs for representatives of different playing roles can be developed.
3. The data obtained indicate the need for a differentiated approach in the training process of young football players, taking into account their playing role. The differentiated approach is more relevant at the age of 15 compared to the age of 12.