THE SOMATOMOTOR PROFILE OF U14 BASKETBALL PLAYERS

. Basketball is a team sport spread all over the world. In recent years, a lot of scientific research has been conducted and highlighted aspects regarding the improvement of physical condition as well as technical and tactical issues specific to the game of basketball. Physical training has become increasingly important in basketball, and players are stronger and more agile, even if their body dimensions are impressive. On the other hand, the game of basketball requires some rigour in motor but especially somatic terms. At international level, there are a number of somatic and motor standards according to which basketball players are selected, but no such scientific approach has been made in our country so far. This study aims to identify the somatic and motor profile of U14 basketball players according to the playing position and to compare the results with those of regional teams from Austria and Greece. The investigated sample consisted of 31 young basketball players, members of the extended team of the Romanian Basketball Federation. The methods used were: literature review, observation, tabular method, mathematical statistics and graphical method. The results show that both the anthropometric and physical test values analysed for each playing position are much weaker for Romanian players than for those from Greece and Austria.


Introduction
Basketball is a dynamic and complex team game that combines explosive movement structures, for example, short sprints, abrupt stops, fast changes in direction, acceleration and vertical jumps, which are associated with various technical structures such as dribbling, different shots and passes (Erčulj et al., 2010).Basketball success depends on several factors, including the morphological one, for instance, height, body mass, arm span and body composition (Ostojic et al., 2006).
Scientific research on physical fitness testing in sports games such as basketball is considerably less than in individual sports such as athletics or tennis.In sports games, team performance depends on a wide range of movements and has complex demands that involve a combination of technical and tactical strategies, physical condition, motivational and psychological elements (Trninić & Dizdar, 2000).In recent years, the game of basketball has greatly developed and quickly spread worldwide.This phenomenon has led to placing more emphasis on the physical, tactical and technical training of athletes with the help of a sportspecific test battery for the development level of motor abilities, but also on their anthropometric data.By using these tests, one can track the changes undergone by athletes over time, assess the effectiveness of training programmes and select players to become members of national teams.However, the athlete's playing position, playing level, age and gender should be taken into account when analysing the data obtained from assessment tests.
In the last few decades, basketball has developed a lot and thus the number of adolescents involved in this sport has increased significantly.For this reason, the selection of the most talented ones is a necessity (Marić et al., 2013).Motor abilities have an important role in both the selection of young basketball players and the progress of their athletic performance.This is especially true for those abilities that are innate and difficult to develop up to a higher level only through training so as to meet the requirements of modern basketball.The motor, physiological and psychological aspects as well as the on-court performance of basketball players have been analysed by several specialists in the field (Torres-Unda et al., 2013;Silva et al., 2013); all these features are also somewhat affected by the anthropometric characteristics of athletes (Popović et al., 2013;Marić et al., 2013).
According to the literature, the game of basketball includes some essential factors that predict sports performance, for example, the identification of body composition and somaticfunctional components (Vaquera et al., 2015).By assessing these components, specialists in the field are able to select potential athletes (Martín-Matillas et al., 2013) and thus support coaches in planning optimised training programmes (Ziv & Lidor, 2009).During a basketball game, players often perform more than 2,700 intermittent-intensity actions that involve acceleration, deceleration and jumps (Scanlan et al., 2011).Recent studies have shown that high body mass and body fat values and therefore a high endomorphic index have negative effects on anaerobic performance that requires sprinting and jumping skills (Nikolaidis et al., 2014;Ribeiro et al., 2015).Thus, an inappropriate feature of the anthropometric profile may limit the performance of basketball players during the game.Previous studies conducted on athletes from different team sports reveal that a certain type of specific profile is needed for each playing position (Ramos-Campo et al., 2014).
There is a broad consensus on the anthropometric differences between basketball athletes playing in different positions; thus, centres and power forwards are significantly taller and heavier than point guards (playmakers), and centres are significantly heavier than the other players (Pojskic et al., 2015).Legg (2017) states that the positional classification of players can be done based on their anthropometric attributes, confirming that centres and power forwards are taller and heavier than playmakers.For a better comparison between players of different body dimensions, Palheta et al. (2019) suggested the use of allometric scaling instead of ratio standards.These authors have found that allometric scaling models can successfully explain the influence of body dimensions on performance because they allow for predicting more efficiently the players' future performance.The study by Jakovljević et al. (2011) indicates that outer players (point guards, shooting guards and small forwards) have a higher ability to accelerate than inner players (power forwards and centres).Köklü et al. (2011) also suggest that acceleration variables are appropriate to distinguish between playing positions.
Many studies aimed to determine whether the sprint performance of basketball athletes playing in different positions was different.Thus, some experts (Boone & Bourgois, 2013) found significant differences in sprint performance between playing positions, while others (Strumbelj et al., 2015) obtained negative results in this regard.Scanlan et al. (2014) tested 12 adult male basketball players competing in the Queensland Basketball League and found that frontcourt players had "superior closed-skill agility performance than backcourt players" (p.1319).Strumbelj and Erculj (2014) reported similar results for female basketball players, namely a significant difference in speed performance depending on the playing position, probably due to differences in height and body weight, which greatly influence the ability to accelerate.This is consistent with the results of the study by Boone and Bourgois (2013), who collected data from 144 elite basketball players and found that taller and heavier centres were slower in sprint tests (10 m and 5 × 10 m).
A considerable amount of studies in the literature demonstrate that shorter players have better performance not only in speed tests but also in agility tests (Pojskic et al., 2015).Some authors (Scanlan et al., 2014) support the idea that agility tests could be useful indicators to determine the most appropriate playing position for an athlete.Experts have highlighted the importance of agility skills during position specialisation, including T-Drill Agility Test (Köklü et al., 2011).The Lane Agility Drill is the most sensitive test to identify positionspecific disparities in change-of-direction speed performance (Stojanović et al., 2019).
Several researchers have reported that body dimensions and therefore strength values can differ significantly between playing positions (Strumbelj et al., 2015).
An athlete's body dimension largely determines their playing position in team sports.This approach is a consequence of an almost universally accepted basketball strategy, which refers to placing the tallest and heaviest players in key positions close to the basket, while shorter players are placed in perimeter positions (Trninić & Dizdar, 2000).This strategy will allow shorter offensive players to move faster with the ball across the court, and taller and stronger players, to move closer to the basket.
In recent decades, many investigations on the anthropometric profile of athletes have been conducted to identify morphological differences between them (Puwar & Upadhya, 2013), depending on each one's playing position and competitive level (Rivera-Sosa et al., 2016).In contrast, there are few studies on the anthropometric profile of athletes and their final results in tournament rankings.In this regard, Martín-Matillas et al. (2013) present a study where they investigate the morphological profile of female basketball players according to their team performance ranking.Another research (Gantois et al., 2017) examines basketball players in the first and second divisions and suggests that, depending on the game demands, competition level and ranking, a specific anthropometric profile is needed, which can contribute to the process of player selection and training for each game position.
Motor performance in childhood and adolescence is associated with the growth and maturation processes.Individuals with early maturation have an advantage in terms of explosive power, anaerobic power, isometric power, strength and speed over those whose biological development has started later.These phases occur between 12 and 15 years of age in boys and 10-14 years of age in girls.(Ramos et al., 2020) The selection of players for junior basketball can be strongly influenced by their maturation and physical development processes.Several studies (Matthys et al., 2012) have reported significant increases in height, weight, running speed, endurance, agility and strength during adolescence.Although the process of talent selection in basketball starts at an early age, the literature mainly focuses on professional senior athletes; therefore, knowledge about the somatic and functional factors that influence the performance of young players needs to be deepened (Ramos et al., 2020).

Body dimension and playing position
Position-specific tasks and body size characteristics in basketball are well known (for example, centres are significantly taller and heavier than guards and forwards) (Boone & Bourgois, 2013;Pojskic et al., 2015).Differences in specific physical condition between playing positions have also been studied (Vaquera et al., 2015).
The five playing positions in a basketball team can be classified in different ways, primarily based on athletes' body dimension, physical condition and skills.The most detailed system classifies each player according to their on-court position.
The point guard or playmaker (position 1) is mainly responsible for handling the ball on the court and coordinating the team's offence.Players are agile and shorter, are excellent passers, have a very good vision of the game and coordinate offence actions.
The shooting guard (position 2), as the team's defensive specialist, is the best shooter, uses team blocks to throw to the basket and scores a large number of points.
The small forward (position 3) makes the best cuts to the basket in an attempt to get open for shots.Players are good long-range shooters, using speed and strength in their actions.This position is characterised by versatility and polyvalence, which is why athletes are often called 'utilitarian players'.They should be able to do almost everything on the court, namely to guard multiple positions, as the case may be.
The power forward (position 4) is the team's most powerful player who is responsible for aggressive play close to the basket, for example, in order to gain possession of the ball after a missed shot.As main characteristics, players are very tall, are good at rebounding, are good shooters and can set up excellent screens.
The centre (position 5) is the team's biggest player who is responsible for scoring near the basket and coordinating the team's defence.Players are the tallest and strongest in the team and are skilled at gathering rebounds.
The differences between centres, forwards and guards in terms of movement patterns and intensity are pointed out by Abdelkrim et al. (2007), who suggest that there are significant differences between the time spent by them in high-intensity movements (14.7%, 16.6% and 17.1%, respectively).A shooting guard or small forward can also play as a centre or a shooter can also play as a power forward, so point guards, shooting guards and small forwards can be classified as 'short', while power forwards and centres are considered to be 'tall'.(Table 1)

Methodology
The purpose of this research was to analyse the anthropometric and physical characteristics of U14 basketball players selected for the extended team of Romania, outlining their somatomotor profile by playing position and comparing the results with basketball players from Austria and Greece.We also tried to verify the hypothesis according to which the measured somatic values could influence the motor results of Romanian athletes compared to foreign players.

Participants
The research sample consisted of 31 junior male basketball players aged 13-14 years (U14 category).They were selected from all over the country to be included in the extended team of the Romanian Basketball Federation.Their basketball experience was about 5.4 years.

Testing procedures
All measurements were performed on the second day of the trial to avoid any influence of player fatigue on the results.The trial was organised in Ploiești by the Romanian Basketball Federation, and its main purpose was to make a preliminary selection among a larger group of potential candidates for the U14 national junior team.

Anthropometric measurements
To establish the somatic and motor profile of the potential players, anthropometric measurements (height, weight, and arm span) were performed, and then their body mass index (BMI) was calculated.

Physical tests
Prior to the physical tests, all participants performed a 20-minute warm-up consisting of running exercises followed by dynamic and static stretching.Players were given 10 minutes of passive rest between tests, hydration breaks and extra rest time.Each athlete received verbal instructions and was encouraged.
For the assessment of change-of-direction speed performance, a reliable and valid instrument was used, namely the Agility T-Test (Sassi et al., 2009), which was conducted on an outdoor basketball court (Figure 1).The test includes forward, backward and lateral running but also basketball-specific movements such as traveling in a fundamental position.Each player covered a total distance of 36.56 m.Two attempts were made, and the times were recorded with an accuracy of one hundredth of a second using an electronic timing system.Athletes took a standing start at the sound signal, 0.5 m behind the first starting line.

Figure 1. Agility T-Test
The Beep Test involves running back and forth between two markers placed 20 meters apart, following audio cues that dictate the required running speed (Figure 2).At regular intervals, the running speed increases, and the test continues until the participants are no longer able to keep up with the required pace.The main purpose of this test is to measure maximum aerobic endurance fitness.Many studies have shown that the Beep Test is a good predictor of a person's maximum oxygen consumption.

Figure 2. Beep Test
Vertical jump was used to test the explosive power of the lower limbs.The player was measured in the standing position with the arm outstretched.The jump was performed with the lower limbs outstretched, recording the height at which the benchmark was reached.The difference between the two measurements represents the player's performance.The player was given two attempts and the best was recorded.
Speed was measured using Microgate, a portable wireless timing system that records the values in sprint tests (10 m, 20 m and 3 x 10 m shuttle).Players took a standing start and were timed individually.The time needed to complete the test was measured in seconds and hundredths of a second using a photoelectric cell device.The best time of two attempts was recorded.The test battery also consisted of coordination and explosive power measurements, for example, standing long jump and jumping over 30-cm-high hurdles for 30 seconds.

Results and Discussion
The results of specialised studies that also investigated athletic performance in terms of agility according to the playing position showed that sometimes the results recorded in agility tests were better for guards than power forwards and centres (Boone et al., 2013).However, the study by Scanlan et al. (2014) reported opposite results, with higher agility performance observed in frontcourt players (small forwards, power forwards and centres) compared to backcourt players (point guards and shooting guards).Finally, a more recent study did not show significant positional differences in agility, which was assessed by three different tests (Sisic et al., 2016).In our study, Romanian athletes recorded significantly better results than foreign players, despite their anthropometric characteristics, for example, our centres were shorter than foreign centres.
The present analysis includes descriptive statistics, ANOVA analysis and factor analysis.• in the 10 m sprint test, Romanian athletes achieved an average of 2.01, which is higher than the average obtained by the athletes from Greece (1.94) and Austria (1.95);

Descriptive statistics
• in the 20 m sprint test, Romanian athletes achieved an average of 3.48, which is higher than the average obtained by the athletes from Greece (3.19) and Austria (3.10); • the average height of Romanian athletes is 1.76 m, therefore it is lower than that of athletes from Greece (1.86) and Austria (1.99); • the average weight of Romanian athletes is 61.91 kg, therefore it is lower than that of athletes from Greece (76.82 kg) and Austria (96.92 kg) this confirms that, in recent years, Romania has faced a problem as regards the athletes' height; • the average BMI of Romanian athletes is 19.89, therefore it is a little a higher than that of athletes from Greece (19.42) and Austria (19.87); this means that Romanian athletes are a bit heavier, so their adipose tissue/muscle mass ratio is positive; • the average vertical jump of Romanian athletes is 49.13, therefore it is lower than that of athletes from Greece (60.91) and Austria (55.14); • in the Agility T-Test, Romanian athletes achieved an average of 10.91, which is higher than the average obtained by the athletes from Greece (10.21) and Austria (10.21).
For most of the variables related to Romanian athletes, a very small standard deviation is observed, which reflects the homogeneity of the group.However, for the variables: hurdle jump, vertical jump and body weight, the standard deviation is high, which shows great differences between Romanian athletes as regards these characteristics.Table 3 and Figure 4 (a, b) show that Romanian centres (position 5) have lower results in speed and agility tests such as 10 m, 20 m and T-Test, but also that their average height is lower.However, the average vertical jump has smaller values for Romanian athletes, although their weight and BMI scores are lower, and these characteristics are identical with those mentioned for position 1.According to the findings of specialised studies, centres are taller than point guards, and this is also confirmed in our case.In this regard, the investigations conducted by Boone and Bourgois (2013) and Ponce-González et al. (2015) on elite basketball players show that centres are much taller and heavier than guards and forwards, so our results with juniors are decisive for the pattern of this profile.Table 3 and Figure 5 (a, b) show that Romanian shooting guards (position 2) have lower results in speed and agility tests such as 10 m, 20 m and T-Test, but also that their average height is lower.However, the average vertical jump has smaller values for Romanian athletes, although their weight and BMI scores are lower, and these characteristics are identical with those mentioned for positions 1 and 5. Table 3 and Figure 6 (a, b) show that Romanian small forwards (position 3) have lower results in speed and agility tests such as 10 m, 20 m and T-Test, but also that their average height is lower.However, the average vertical jump has smaller values for Romanian athletes, although their weight and BMI scores are lower, and these characteristics are identical with those mentioned for positions 1 and 2. Table 3 and Figure 7 (a, b) show that Romanian small forwards (position 4) have lower results in speed and agility tests such as 10 m, 20 m and T-Test, but also that their average height is lower.However, the average vertical jump has smaller values for Romanian athletes, although their weight and BMI scores are lower, and these characteristics are identical for shorter players.According to the findings of specialised studies, power forwards are taller than playmakers or guards, but this is not confirmed in our case.The analysis of variance (ANOVA) confirms our previous conclusions and allows extrapolating them to the entire statistical population in the conditions of a representative sample.F-value is higher than F-critical, and P-value is lower than 0.05 for the playing position, the assessment tests and the country.This leads us to state that there are significant differences between the somatomotor profile of players depending on the playing position, assessment tests and the country.

Confirmatory Factor Analysis (CFA)
CFA is achieved by using Structural Equation Modeling (SEM).The model can estimate saturation levels and therefore calculate a number of fit indices that describe how well the model matches the data or, in simpler terms, how well the model is able to describe the observations.SmartPLS software provides many tests that can be used to ensure a coherent The somatic variable (somatic characteristics of Romanian athletes) has a high value for the Composite Reliability Model (0.832 > 0.6 min threshold), Cronbach's Alpha (0.814 > 0 min threshold), rho_A (0.858 > 0.7 min threshold) and AVE (0.561 > 0.5 min threshold).It can be noted that, for the motor variable, the load factors have very small values and therefore an insignificant influence within the model.(Table 4) For this model, the path coefficient coincides with the correlation coefficient (-0.821), which has a very high negative value, meaning that the somatic aspect has a decisive influence on motor skills.High somatic values (e.g., high body weight) negatively influence motor performance (Table 5).All values less than 5 express the lack of collinearity (Figure 9).Values less than 3 express non-existent collinearity.In our analysis, there is no collinearity due to the elimination of variables representing this phenomenon, namely BMI and 20 m.Variables measuring the same characteristic in different ways were removed.

Conclusion
Anthropometric values, along with physical values, can be considered an important component for the creation of a performance profile.Thus, outlining the somatomotor profile of an athlete can help coaches in the selection and guidance of junior players towards achieving success in the game of basketball.
Specialised studies support the idea that the values of agility, speed and jump tests are decisive factors for basketball players, and anthropometric measurements would be the strongest factor of discrimination between them.Thus, these values should be taken into account in the selection process.
Given that the choice of a permanent playing position is not recommended at the age of 13-14, we have tried to summarise the characteristics of motor and somatic assessment tests in order to facilitate the distinction between playing positions and thus establish the best positions on the basketball court for a player at the beginning of their development.
As expected, it has been shown that the anthropometric values of Romanian players are much lower than those of players from Greece and Austria, and their results in physical tests such as speed and agility are much weaker the values of foreign players.This proves that somatic values such as height and weight influence the results achieved in physical tests compared to foreign players, and thus our research hypothesis is valid.
Therefore, agility, speed and anaerobic endurance should be tested during postspecialisation by paying special attention to anthropometric data.Moreover, the training process should be individualised.On the other hand, although weight and height influence the results of physical tests, our findings have indicated that increased BMI in some players leads to a decrease in speed and jumping performance compared to other players whose BMI is within the normal range.This performance is crucial in basketball and should be considered as an integral part of any sports training programme.This information could help coaches to both establish a pattern for the characteristics of 14-year-old players, which is consistent with each specific playing position, and design specific training programmes according to the playing position of each individual player.In addition, the weight and BMI values of Romanian athletes could be modified by training and diet; it is worth noting that these values are a starting point in making nutritional and dietary changes and calculating the appropriate training load.The obtained normative data could be a useful tool in talent detection programmes designed for the game of basketball.
Authors' Contributions: All authors have equally contributed to this study.

Informed Consent Statement:
The participants provided their written informed consent to participate in this study.

Figure 3 .
Figure 3. (a) Profile of the point guard for Austria (A), Greece (GR) and Romania (RO)

Figure 4 .
Figure 4. (a) Profile of the centre position for Austria (A), Greece (GR) and Romania (RO)

Figure 4 .
Figure 4. (b) Profile of the centre position for Austria (A), Greece (GR) and Romania (RO)

Figure 5 .
Figure 5. (a) Profile of the shooting guard for Austria (A), Greece (GR) and Romania (RO)

Figure 6 .
Figure 6.(a) Profile of the small forward for Austria (A), Greece (GR) and Romania (RO)

Figure 7 .
Figure 7. (a) Profile of the power forward for Austria (A), Greece (GR) and Romania (RO)

Figure 8 .
Figure 8. Relationship between somatic and motor data

Table 1 .
Classification of basketball playing positions and their major responsibilities

Table 2 .
Physical test results and somatic characteristics -A comparison between Romania, Greece and Austria

Table 3 .
Physical test results and somatic characteristics depending on the playing position -A comparison between Romania, Greece and Austria

Table 4 .
ANOVA: Two-Factor with Replication

Table 5 .
Model validation criteria (Construct Reliability and Validity)