Differences in morpho-functional characteristics among young soccer players according to their playing positions

Abstract

Abstract:The aim of this study was to determine differences among young soccer
players in terms of fitness characteristics based on their position in the team. The
study included 152 players, aged between 12 and 18, divided into three groups
according to their age, as well as in subgroups based on the position they played.
Results indicates that, among the players under 14, were no significant difference
between observed variables. As for the differences among players under 16, they
were noted in values of body weight between goalkeepers and midfielders
(p=0.012), goalkeepers and forwards (p=0.013), and regarding the level of agility,
between the goalkeepers and defenders(p=0.024), as well as midfielders
(p=0.033). In addition to these, difference were observed between the goalkeepers
and players at other positions regarding to the maximal oxygen uptake (p=0.001;
p=0.000; p=0.017). Looking at the under 18 soccer players, significant differences
were noted between goalkeepers and other players when it comes to level of
agility (p=0.010; p=0.010; p=0.040), values of maximal oxygen uptake (p=0.014;
p=0.021; p=0.017), as well as differences in body mass between goalkeepers and
defenders (p=0.029), and also between defenders and midfielders(p=0.019). These
results showed that, among the players under 14, no differences were observed, as
was expected, while differences among players under 16 and 18 were noticed,
which may be prescribed to period of significant growth and development, as well
as beginning of specialization process in solving certain soccer tasks.
Key words: soccer, fitness assessment, maximal oxygen uptake

Full text

ФИС Комуникације 2011
32
UDK 796:616-071
Драгољуб Вељовић
Бојан Међедовић
Факултет за спорт и туризам, Нови Сад
Мирјана Стојановић
Центар за здравље, вежбање и спортске науке, Београд
Марко Стојановић
Факултет спорта и физичког васпитања, Нови Сад
Сергеј М. Остојић
Факултет за спорт и туризам, Нови Сад
Драгољуб Вељовић, Бојан Међедовић, Мирјана Стојановић, Марко Стојановић, Сергеј М
Остојић
РАЗЛИКЕ У МОРФО-ФУНКЦИОНАЛНИМ
КАРАКТЕРИСТИКАМА МЕЂУ МЛАДИМ ФУДБАЛЕРИМА
ПРЕМА ПОЗИЦИЈИ У ТИМУ
Апстракт: Циљ ове студије био је да се утврде разлике међу младим
фудбалерима у погледу морфо-функционалних карактеристика на основу
позиција у тиму. У истраживању је учествовало 152 фудбалера, старости
између 12 и 18 година, подељени у три групе према узрасту, као и у
подгрупе на основу позиција које су играли. Резултати указују да међу
фудбалерима пионирског узраста није било значајних разлика. Када су у
питању разлике међу кадетима, исте су уочене у вредностима телесне масе
између голмана и играча средине терена (p=0.012), голмана и нападача
(p=0.013), као и по питању нивоа агилности између голмана и фудбалера
одбране (p=0.024) и играча средине терена (p=0.033). Поред ових варијабли,
међу кадетима уочена је и разлика између голмана и фудбалера на другим
позицијама када су у питању вредности максималне потрошње кисеоника
(p=0.001; p=0.000; p=0.017). Посматрајући фудбалере омладинског узраста,
уочене су статистичке значајне разлике између голмана и осталих играча
када су у питању ниво агилности (p=0.010; p=0.010; p=0.040) и вредности
максималне потрошње кисеоника (p=0.014; p=0.021; p=0.017), као и разлике
у телесној маси између голмана и одбране (p=0.029), али и између фудбалера
одбране и средине терена (p=0.019). Добијени резултати указују да међу
фудбалерима пионирског узраста није било разлика у посматраним
карактеристикама, што је и било очекивано, док су разлике биле уочене
међу фудбалерима кадетског и омладинског узраста, што се може преписати
периоду значајнијег раста и развоја, али и почетку специјализације у
решавању одређених фудбалских задатака.
Кључне речи: фудбал, дијагностика, максимална потрошња кисеоника

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33
DIFFERENCES IN MORPHO-FUNCTIONAL
CHARACTERISTICS AMONG YOUNG SOCCER PLAYERS
ACCORDING TO THEIR PLAYING POSITIONS
Abstract:The aim of this study was to determine differences among young soccer
players in terms of fitness characteristics based on their position in the team. The
study included 152 players, aged between 12 and 18, divided into three groups
according to their age, as well as in subgroups based on the position they played.
Results indicates that, among the players under 14, were no significant difference
between observed variables. As for the differences among players under 16, they
were noted in values of body weight between golkeepers and midfielders
(p=0.012), goalkeepers and forwards (p=0.013), and regarding the level of agility,
between the goalkeepers and defenders(p=0.024), as well as mildfielders
(p=0.033). In addition to these, difference were observed between the goalkeepers
and players at other positions regarding to the maximal oxygen uptake (p=0.001;
p=0.000; p=0.017). Looking at the under 18 soccer players, significant differences
were noted between goalkeepers and other players when it comes to level of
agility (p=0.010; p=0.010; p=0.040), values of maximal oxygen uptake (p=0.014;
p=0.021; p=0.017), as well as differences in body mass between goalkeepers and
defenders (p=0.029), and also between defenders and midfilders (p=0.019). These
results showed that, among the players under 14, no differences were observed, as
was expected, while differncess among players under 16 and 18 were noticed,
which may be prescribed to period of significant growth and development, as well
as beginning of specialization proces in solving certain soccer tasks.
Key words: soccer, fitness assessment, maximal oxygen uptake
INTRODUCTION
Soccer is a team sport, and therefore, a victory over opponent, as the ultimate goal
of a soccer match, depends both on the individual quality of each player and mutual
compatibility between them (Gil, S., Gil, J. & Ruiz, 2007). Therefore, for greater
efficiency, players are allocated to different positions in order to fulfill specific tasks
and ensure their team superiority (Stølen Chamari, & Castagna., 2005; Wong et al.,
2009). In most studies, as in soccer practice, players are usually classified into four
groups: goalkeepers, defenders, midfielders and forwards (Malina et al., 2000). During
the game, players at different positions have different requirements, as midfielders
cross the biggest distance (between 10 and 13 km), compared with other players in the
field, while goalkeepers run about 4 km in 90 minutes of play (Wisløff, Helgerud &
Hoff, 1998). Due to different requirements during the match, differences were found
among top soccer players according to their fitness characteristics at different playing
positions. For example, the average height of elite players is about 180-185 cm, where
goalkeepers are the tallest and midfielders are shortest, with the weight between 75 and
80 kg (Reilly, Williams, Nevil & Franks, 2000). Fat percentage of soccer players is
lower than sedentary people, but higher than in endurance runners (Shephard, 1999).

ФИС Комуникације 2011
34
The same is between 7 and 19%, where the highest percentage of fat was noted for
goalkeepers, while midfielders have the lowest values of body fat (Wittich et al., 2001).
When it comes to explosive abilities, recent research says that the fastest players are
forwards (Sporis et al., 2009), while the slowest are goalkeepers (Rienzi et al., 2000).
On the other hand, when it comes to vertical jump height, several studies have found
mean values ranging between 38 and 55 cm, where defenders and forwards jump
higher than midfielders (Wisløff et al., 1998; Cometto et al., 2001). In addition to these
parameters, the values of maximal oxygen uptake (VO2max) are directly related to
distance covered during match (Helgerud et al., 2001). Thus, Bangsbo and Michalsik
(2002) found that midfielders have greater value of VO2max than full-backs, which in
turn have a slightly better values than forwards, while center-backs have lowest values
of VO2max, whith the exception of the goalkeepers (Rienzi et al., 2000). However, a
large number of studies, that dealt with the determination of fitness characteristics of
soccer players at different positions, were conducted on a elite seniors, while few of
them were administered on a sample of young soccer players, especially in our country.
Therefore, the aim of this study was to determine possible differences in fitness
characteristics of young Serbian soccer players, while the results from this research can
be used for future analysis, as well as a useful tool for coaches in selection process and
training of young soccer players.
METHOD
The research was conducted at sports center Vujadin Boskov in Veternik. The
study involved young soccer players of FC Vojvodina, which had no major health
problems. All subjects gave their consent and voluntarily participated in this study,
while the research was initiated and approved by Faculty for sport and tourism in Novi
Sad. The study encompassed 152 young soccer players which were divided into age-
related groups (under 14, 16 and 18), as well as according to their position in team.
Fitness characteristics (body height and mass, percentage of body fat, speed at
distances of 5 and 20 m, explosive leg power, agility and maximal oxygen uptake)
were identified for each respondent. Body height was estimated by altimeter (Model
212, Seca, Hanover, USA), while body weight and fat percentage were measured with
the device for bioimpendance (BF622, Tanita, Tokyo, Japan). Running speed was
measured at 20 meters with lap time at 5 meters using a light gate (Ergo Timer, Globus,
Torino, Italy). For the assessment of explosive leg power gage platform was used
(Model S, Axon Jump, Cordoba, Argentina). This test was followed after test for speed
assessment and warm up which include a series of jumps of moderate intensity and
stretching. Jump was repeated twice, and the higher value is taken as the actual result.
Agility was assessed by specific test for soccer players (Svensson & Drust, 2005).
Players were required to run given polygon for the shortest possible time, they had two
attempts, and better recorded time was taken as a result of the test. Finally, maximal
oxygen uptake was estimated by a shuttle-run test (Leger & Lambert, 1982). This test
was carried out last, after all test procedures. Same consisted of running 20-meter
section of a given signal from the CD player. Participants were required to be one foot
over the line when they hear a beep, after which they stopped, turned and ran back. The
test ended when the subject was late to get to the line at a given signal twice in a row,
and maximal oxygen uptake was calculated according to the nomogram
(Rambsbootom, Brewer & Williams, 1988). All participants were measured in the

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morning (at 08:00) and in the afternoon (at 15:00), before their training. Data collected
through the survey were analyzed using descriptive and comparative statistics. From
the descriptive statistics, the mean and standard deviation were determined, while from
area of comparative statistics, a 2-way analysis of variance was used to determine the
difference between the observed variables. For all calculations the statistical software
application for PC, SPSS for Windows – Version 16.0, was used (SPSS Inc., Chicago,
Illinois, USA).
RESULTS WITH DISCUSSION
The results of this study demonstrate that young soccer players of different
positions show differences in antropometric and the phyisiological characteristics,
particulary among soccer players under 16 and 18. Table 1 shows the parameters of
antropometric characteristics of under 14 soccer players along with the parameters of
speed, agility, maximal oxygen uptake and vertical jump, where no significant
difference between variables were observed. Differences among players under 16 are
shown in Table 2. They were noted in values of body weight between golkeepers and
midfielders (p=0.012), goalkeepers and forwords (p=0.013), and regarding the level of
agility, between the goalkeepers and defenders (p=0.024), as well as mildfielders
(p=0.033). In addition to these, difference were observed between the goalkeepers and
players at other positions regarding to the maximal oxygen uptake (p=0.001; p=0.000;
p=0.017). Looking at the under 18 soccer players, significant differences were
observed between goalkeepers and other players when it comes to level of agility
(p=0.010; p=0.010; p=0.040), values of maximal oxygen uptake (p=0.014; p=0.021;
p=0.017), as well as differences in body mass between goalkeepers and defenders
(p=0.029), and also between defenders and midfilders (p=0.019), as it is shown in
Table 3.
Table 1. Fitness characteristics of under 14 soccer players – mean (SD).
Goalkeeper
(n = 5)
Defender
(n = 21)
Midfielder
(n = 20)
Forward
(n = 11)
p value*
Body height (cm)
160.2 ± 3.5
159.9 ± 2.9
159.1 ± 2.4
158.2 ± 3.1
NS
Body weight (kg)
51.3 ± 2.7
52.1 ± 3.1
49.9 ± 2.4
50.1 ± 3.1
NS
Body fat (%)
13.9 ± 1.2
13.3 ± 0.9
12.4 ± 1.5
13.1 ± 1.1
NS
Speed – 5 m (s)
1.22 ± .23
1.13 ± .17
1.11 ± .09
1.09 ± .14
NS
Speed – 20 m (s)
3.56 ± .34
3.58 ± .22
3.50 ± .26
3.60 ± .18
NS
Agility (s)
12.58 ± .99
12.35 ± .65
12.51 ± .54
12.07 ± .77
NS
Vertical jump (cm)
34.0 ± 2.4
33.2 ± 1.9
33.5 ± 2.7
34.2 ± 1.6
NS
VO2max (ml/kg/min)
42.2 ± 5.4
44.4 ± 2.5
45.9 ± 3.6
44.8 ± 3.3
NS
* p < 0.05; NS – no significant difference

ФИС Комуникације 2011
36
Table 2. Fitness characteristics of under 16 soccer players – mean (SD).
Goalkeeper
(n = 7)
Defender
(n = 16)
Midfielder
(n = 21)
Forward
(n = 10)
p value*
Body height (cm)
179.1 ± 4.5
176.1 ± 3.9
175.9 ± 3.4
176.2 ± 5.1
NS
Body weight (kg)
67.3 ± 4.7†
65.5 ± 4.1
61.8 ± 3.2
61.5 ± 2.8
0.013
Body fat (%)
12.4 ± 1.5
11.5 ± 1.1
11.9 ± 0.8
11.8 ± 1.2
NS
Speed – 5 m (s)
1.06 ± .13
1.06 ± .21
1.04 ± .12
1.04 ± .16
NS
Speed – 20 m (s)
3.18 ± .43
3.19 ± .31
3.18 ± .16
3.17 ± .22
NS
Agility (s)
12.07 ± .71††
11.01 ± .21
11.11 ± .37
12.01 ± .53
0.024
Vertical jump (cm)
42.0 ± 4.0
40.8 ± 3.5
39.9 ± 4.3
41.1 ± 3.1
NS
VO2max (ml/kg/min)
44.3 ± 4.7‡
51.6 ± 3.9
52.1 ± 2.4
49.9 ± 3.5
0.001
* p < 0.05; NS – no significant difference; † goalkeepers vs. midfielders and
forwards; †† goalkeepers vs. defenders and midfielders; ‡ goalkeepers vs. defenders,
midfielders and forwards
Table 3. Fitness characteristics of under 18 soccer players – (SD).
Goalkeeper
(n = 4)
Defender
(n = 12)
Midfielder
(n = 16)
Forward
(n = 9)
p value*
Body height (cm)
181.3 ± 3.1
180.0 ± 2.7
179.1 ± 2.9
180.2 ± 4.3
NS
Body weight (kg)
78.1 ± 3.2†
74.1 ± 3.8
67.3 ± 4.4††
75.9 ± 2.4
0.029
Body fat (%)
13.1 ± 1.2
11.9 ± 1.5
11.7 ± 0.9
12.1 ± 1.4
NS
Speed – 5 m (s)
1.06 ± .20
1.01 ± .11
1.04 ± .18
1.02 ± .09
NS
Speed – 20 m (s)
3.21 ± .31
3.07 ± .17
3.12 ± .20
3.03 ± .21
NS
Agility (s)
12.97 ± .54‡
11.25 ± .42
11.26 ± .28
11.19 ± .37
0.004
Vertical jump (cm)
45.1 ± 3.1
44.7 ± 2.5
42.4 ± 3.9
45.3 ± 2.9
NS
VO2max (ml/kg/min)
44.4 ± 2.1#
51.4 ± 4.1
52.9 ± 3.5
51.6 ± 2.7
0.002
* p < 0.05; NS – no significant difference; † goalkeepers vs. defenders and
midfielders; †† midfielders vs. defenders; ‡ goalkeepers vs. defenders, midfielders and
forwards; # goalkeepers vs. defenders, midfielders and forwards
Soccer is undoubtedly one of the most popular sports today, and many studies
were conducted on a sample of soccer players with different objectives (Gil et
al., 2007). However, most of them were conducted on top senior soccer players, while
the number of research with young players is significantly lower, especially in our
country. Therefore, in this study, sample was made of young soccer players of FC
Vojvodina from Novi Sad. They were divided according to age categories and the
positions they were playing in the team, as it was the case in relevant studies conducted
so far (Malina et al., 2000; Reilly et al., 2000; Arnasson et al., 2004). Statistically
significant differences in fitness characteristics among players under 14 were not
observed, although it should be noted that the goalkeepers were taller, heavier, slower,
with lower values of maximal oxygen uptake in relation to players who have played in

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37
other positions, as shown in recent study (Wong et al., 2009). On the other hand,
significant differences were observed when it comes to values of body mass between
goalkeepers and other players among under 16 group, which is in correlation with
results of previous studies (Malina et al., 2000). The same was noted among under 18
soccer players, indicating that significant differences were also observed between
defenders and midfielders. Midfielders had lowest values of body mass and body fat,
which indicates that, due to the specific tasks during the match, for this position,
players are selected also by according to their values of body composition (Wong et al.,
2008). Results of this study also showed that among players under 16 and 18,
significant differences were noted according to time spent in solving a specific soccer
agility test between goalkeepers and players at other positions, while no differences
were observed among players in the field, which is in correlation with results presented
by Malina et al. (2005). When it comes to sprint time at 5 and 20 meters, there were no
differences among players under 16 and 18, which isn’t in correlation with the results
obtained in recent studies. According to Malina et al. (2004), forwards are significant
faster than the others, while goalkeepers has the worst results at 20 and 30 meters
sprint, which was also presented in the research of Gil et al. (2007). Therefore, it soon
can be expected, that players who participated in this study, show significant
differences in sprint time, because speed at short distance is a major predictor for
success in some playing positions, such as forwards (Di Salvo et al., 2007). When it
comes to values of vertical jump height, no differences were noted among players
under 16 and 18, which were also presented in previous studies (Malina et al., 2004;
Wong et al., 2009). However, it was observed that goalkeepers had best results, while
midfielders were worst, which can led as to conclusion that in years to come, these
differences will increase and become significant, as defined in the survey of Stølen et
al. (2005) among elite soccer players. Among players under 16 and 18, significant
differences were noted among goalkeepers and other players in values of maximal
oxygen uptake, as presented in research of Reilly et al. (2000). Although, no significant
differences were observed among players in the field, midfielders had highest values of
VO2max, which can be explained by the specificity of playing role, which was found at
top soccer players (Rampinini et al., 2007).
CONCLUSION
Research was conducted on a sample of 152 young soccer players aged between
12 and 18, divided into three subsamples based on the competitive categories (under
14, 16 and 18), and according to the their playing position, in order to determine
differences between the players in terms of fitness characteristics. Results indicate that
among the players under 14, there were no significant difference between observed
variables. As for the differences among players under 16, they were noted in values of
body weight between golkeepers and midfielders, goalkeepers and forwards and,
regarding the level of agility, between the goalkeepers and defenders, as well as
mildfielders. In addition to these, difference were observed between the goalkeepers
and players at other positions regarding to the maximal oxygen uptake. Looking at the
under 18 soccer players, significant differences were observed between goalkeepers
and other players when it comes to level of agility, values of maximal oxygen uptake,
as well as differences in body mass between goalkeepers and defenders and also
between defenders and midfilders. These results showed that among the players under

ФИС Комуникације 2011
38
14 no differences were noted, as was expected, while differncess among players under
16 and 18 were observed, which may be prescribed to period of significant growth and
development, as well as beginning of specialization proces in solving certain soccer
tasks.
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