EXERCISE AND QUALITY OF LIFE
Research article
Volume 4, No. 1, 2012, 35-42
UDC 796.332-051:796.012.1
DIFFERENCES IN SOME MORPHOLOGICAL
CHARACTERISTICS AND THIGH MUSCLE FORCE OF
BOUNCE LEG BETWEEN FOOTBALL PLAYERS AND
GOALKEEPERS
éivko Kalenti„, Dragana Golik-Peri„, Dragan Doder, Nenad Sudarov and Vojin JovanËevi„
Regional Institute of Sport and Sport Medicine - Novi Sad
Abstract
The aim of this study is to determine the differences in certain morphological
characteristics and thigh muscle force of bounce leg between football players and
goalkeepers. The examined group consisted of 15 goalkeepers and 14 players, aged 15 ñ 18
years, from Vojvodina cadet league. Five parameters were tested by means of isokinetic
dynamometer, and 6 morphological factors were measured. The differences between sub
samples were gained by multivariable and univariable analysis of variance. Multivariable
analysis was used to determine significant difference at the level (p =.00), and we determined
statistically significant difference on individual basis in body height and in muscle mass
percentage. Almost equal results in thigh muscle force of bounce leg among the subjects and
no difference in other variables can be explained by identical training process for players and
goalkeepers. The data gathered demonstrate that in the future it will be necessary to
implement different training process, specially designed for goalkeepers.
Keywords: isokinetics, morphology, football players, muscle strength
Introduction
Football is a collective sport where good score cannot be achieved without
unconditional cooperation among team players. Although it is a colective sport, in which
touching the ball with a hand is not allowed, there is a player in a team who is not only
allowed to touch the ball with the hand but who also finds it necessary to do so since it
represents the basic, most commonly used method of his/her play. These players are called
goalkeepers and they represent individuals in the most popular collective sport in the world ñ
football.
Corresponding author. Regional Institute of Sport and Sport Medicine - Novi Sad, 25 Masarikova Street,
21000 Novi Sad, e-mail: sudartri@yahoo.com
© 2012 Faculty of Sport and Physical Education, University of Novi Sad, Serbia
é. Kalenti et al.
The purpose of the science in the field of monitoring and application of contemporary
technonogical advancements is to find and establish the principles of transformational
processes of morphological characteristics which are important for football, whereas training
technology should find out optimal training content for the transformation of the above
mentioned characteristics. In order to implement technological and scientific advancements in
an adequate manner and to minimise any possible errors, it was interesting to find out whether
there were differences among players and goalkeepers and if they ought to be treated in the
same way. The aim of this research is to try to demonstrate that the differences concerning
thigh muscle force and some morphological characteristics exist among different players.
The word isokinetics originates from Greek words iso ñ constant and kinesis ñ
movement, so we can translate it as the movement at the constant speed. Isokinetic exercises
are performed at constant speed, with the resistance being adjusted and changed during the
movements (according to Lohman, 2008). The musculature is under the maximum load
during the whole movement range. Muscle effort is of an extremely high intensity and it is
distributied on the whole area of the movement, with little load on the examined and trained
ankle itself. The resistance which is produced by the device is proportional to the used force,
so the possibility of injuring or overloading the ankle is minimised.
Numerous authors from the sportís world were researching morphological and motoric
space of the football players (Radosav, 1990; Smaji„, 2005; St¯len, Chamari, & Castagna,
2005; Svensson & Drust, 2005; Vujovi„ & Veljovi„, 2010; Williams, 2000; Molnar, Popovi„
& Smaji„, 2007,), while some other authors were exploring isokinetic space (Doder, Golik-
Peri„, & Babiak, 2006; Doder, Savi„, & Golik-Peri„, 2008, Madi„ et al. 2008, Golik-Peri„ et
al. 2011), and research concerning isokinetic space of the football players was conducted by
the following authors (Kalenti„, JovanËevi„, & Milojkovi„, 2009; Golik- Peri„ et al., 2011;
Vujkov, Golik-Peri„, Drid, Vujkov, & Drapöin, 2008, Gutovi„, Sudarov, Fratri„, & Golik-
Peri„, 2011). They came to the conclusion that there was statistically significant difference in
the force of a movement of flexion in favour of the attackers comparing to the players in other
positions of the team.
Matkovi„ et al. (2003) concluded that only goalkeepers differ from the rest of the
players regarding variable body height and body weight, whereas the rest of the players did
not show statistically significant difference regarding any of the examined variables.
Swedish experts in isokinetics field of expertise (Oberg, Ekstrand, Moller & Gillquist,
1984) tested 180 football players of an elite competition range which were divided into 4
groups (goalkeepers, defence players, midfielder and attackers) in relation to their muscle
force and flexibility of lower extremity of weaker leg. They came to the conclusion that the
goalkeepers and defence players had statistically significant higher values of peak torque
extension than the attackers, while the attackers had statistically important higher values of
rational execution of movements flexion/extension than the goalkeepers and defence players.
Goalkeepers also had the best results at the flexibility test.
The aim of this research is to determine whether there are differrences in certain
morphological characteristics and thigh muscle force of bounce leg between football players
divided into sub sample groups according to their positions in the team.
36
Differences between football players and goalkeepers
Method
Participants
Sample group consisted of 29 football players from Vojvodina cadets league who
were divided into two sub sample groups according to their positions in the team (15
goalkeepers and 14 players) aged 15 ñ 18 years.
Instruments and procedures
Testing was conducted by means of Easytech ííPrima DOCíí isokinetic dynamometer,
with peak torque moment of 60°/sec. The system of 5 tests was used in this research:
maximum strength of extensors
(EXTP) and flexors
(FLEXP), maximum strength of
extensors (EXTP) and flexors (FLEXP) in relation to the body mass and relationship between
agonists and antagonists (AGANT) of the bounce leg.
Six morphological factors were measured: body height (TV), body weight (TM),
bounce leg thigh circumference (ONAT), subcutaneous adipose tissue of thigh of the bounce
leg (NABN), muscle mass percentage (MASP) and adipose tissue mass percentage (MTKP)
of the players examined.
Testing protocol: on the day of the testing the players did not have practice and the
measuring was performed strictly according to the standard protocol. All sportsmen were
familiar with the standard testing on the device for isokinetic measuring. All sportsmen had
done warm up exercices on the dynamometer before they were tested and in the standard test
they were conditioned into the optimal state for testing.
Apart from descriptive statistics, the significance of the difference among the tested
groups of players of the whole sample group was established by means of multivariable
analysis of variance
(MANOVA), while the significance of differences in individual
arithemtic means of the variables was calculated by means of univariable analisys of variance
(ANOVA) at the level of significance of p ≤ .05.
Results
Most of the applied morphological and isokinetic variables do not deviate significantly
from the normal distribution (table 1). This shows that the tests chosen were discriminatory
enough, except regarding the variable MKTP (2,45) where the results show tendency towards
the lower values from the normal distribution. (Modus ñ Mo is in small values zone), and
MASP (-2,25) where the results show the tendency towards higher values (Modus ñMo is in
higher values zone) from the arithmetic mean. The degree of the curve at the peak of the
curve line, which represents distribution of the results, is mesokurtic and platykurtic, except
for the variables NABN (2,67), MASP (9,12) and MKTP (7,39) where the peak is leptokurtic.
37
é. Kalenti et al.
Table 1
Central and dispersional parameters of morphological and isokinetic variables
Variables
N Min
Max
M
SD Skewnes Kurtosis
TV
29
168.60
194.60
181.40
6.32
.08
-.48
TM
29
51.90
85.70
73.31
8.76
-.66
-.09
ONAT
29
4.00
61.70
54.59
4.20
-.74
.12
NABN
29
4.00
17.50
9.67
2.64
.73
2.67
MASP
29
23.80
58.10
47.79
5.95
-2.25
9.12
MKTP
29
5.20
29.30
10.53
4.86
2.45
7.39
EXTP
29
119
379
261.00
57.43
-.44
.75
FLEXP
29
60
198
110.93
36.81
.68
.27
EXTPR
29
228
468
354.59
65.03
-.12
-.65
FLEXPR
29
92
254
150.03
42.95
.76
.09
AGANT
29
24
63
42.17
9.63
.09
.04
N ñ number of players; Min ñ minimal result value; Max ñ maximal result value; M ñ arithmetic mean; SD ñ
standard deviation ; TV ñ body height, TM ñ body weight, ONAT ñ thigh circumference, NABN ñ thigh
skinfold, MASP ñ adipose tissue percentage , MKTP ñ muscle mass percentage. Maximum torque peak of
extensors (EXTP) and flexors (FLEXP), maximum torque peak of extensors (EXTPR) and flexors (FLEXPR) in
relation to the body weight and relationship between agonists and antagonists (AGANT), bounce leg
Table 2 shows that the multivariable statistic significance between arithmetic means of
the goalkeepers (AX1) and players (AX2) is at the level of .00 (p = .00), while the statistic
significance gained by the use of univariable means was obtained only for the variable of
body height (TV) at the level of .02 (p = .02); the muscle mass percentage (MASP) at the
level of .02 (p = .02); the difference in the force of the thigh musculature of agonists and
antagonists (AGAN) was p = .06, so this significance is at the very border of the statistic
significance in favour of goalkeepers.
38
Differences between football players and goalkeepers
Table 2
Statistic parameters of univariable and multivariable analysis of variance
(ANOVA/MANOVA)
Variables
M1
M2
SD1
SD2
F
p
TV
184.06
178.55
6.35
5.09
6.59
.02
TM
75.66
70.80
8.83
8.28
2.33
.14
ONAT
55.30
53.84
3.94
4.49
.87
.36
NABN
9.81
9.54
3.60
1.03
.07
.79
MASP
50.27
45.14
4.46
6.34
6.42
.02
MKTP
12.09
8.86
6.40
1.05
3.48
.07
EXTP
263.27
258.57
59.16
57.65
.047
.83
FLEXP
121.13
38.71
38.91
9.63
2.52
.12
EXTPR
344.60
365.29
64.60
66.17
.72
.40
FLEXPR
158.27
141.21
44.75
40.68
1.15
.29
AGANT
45.40
100.00
8.749
32.24
3.84
.06
= .44 F = 10.91 p = .00*
M1 ñ arithmetic mean of the 1st group (goalkeepers); M2 ñ arithmetic mean of the 2nd group (players); SD1 ñ
standard deviation of the 1st group (goalkeepers), SD2 ñ standard deviations of the 2nd group (players); -Wilk's
lambda; F -test; p - statistic significance
Statistically significant difference was determined by multivariable analysis of
variance (MANOVA) of the whole sample group between sub samples at the level of p<.00.
Discussion
The research of certain morphological characteristics and the force of the thigh
musculature of the bounce leg of the football players who were divided into two groups
according to the position they play in the team (goalkeepers and players) and who were tested
on the isokinetic dynamometer PrimaDOC (EASYTECH ñ Italy) in Regional Institute of
Sport and Sport Medicine in Novi Sad, showed the results which do not coincide with the
previous research in this field of interest.
39
é. Kalenti et al.
Descriptive analysis determined mostly normal distribution of the results, with the
increased values of skewness (distribution is positively asymmetric) for the variable MKTP
(2,45), indicating a tendency for lower values from the normal distribution, and MASP (-2,25)
where the distribution is negatively asymetric, i.e. the results show tendency for higher value
from the normal distribution.
The results of the univariable analysis of variance (ANOVA) show that there is a
statistically significant difference among the players divided according to their positions in
the team regarding their body height (TV) p = .02 and muscle mass (MASP) p = .02 in favour
of goalkeepers. This could be anticipated, since the goalkeepers have special tasks during the
match where the body height is an advantage. It is well known fact that goalkeepers often
have short moving tasks which end in explosive jumps, contrary to the players who spend
most of the training and match in constant running. That is probably the reason why the
players have lower values of percentage of adipose tissue comparing to the goalkeepers.
Statistically significant difference between the sub samples was obtained only in
comparison of agonists and antagonists (AGANT) p = .06 by analysing the force of the thigh
musculature. That significance is at the very border in favour of goalkeepers, whereas in other
examined variables there is no difference among the players concerning their bounce legs.
This research did not confirm the research in the field of isokinetics done by the
Swedish scientists, who came to the conclusion that the goalkeepers and defence players had
statistically significant higher values of peak torque extension comparing to the attackers,
while the attackers had statistically significant higher values of the rational execution of
movements flexion/extension (HQ RATIO) comparing to goalkeepers and defence players.
A possible cause of this non-confirmation of results of Swedish authors may be lying
in fact that this research used the results of the tests performed on the players who compete in
cadets league, who are still developing. For this reason they were not subjected to the same
training process as the elite football players who were used in the research done by the above
mentioned authors.
The results of the univariable analysis of variance show us that there is a statistically
significant difference regarding body height and muscle mass percentage among players
divided according to the positions in the team, and the relationship between agonists and
antagonists was at the border of the statistic significance in favour of goalkeepers. In other
examined variables there is no difference concerning bounce legs of the players. One has to
bear in mind the fact that the examined group consisted of players of cadet league, and that, in
most football clubs, this is the period when the goalkeepers are directed to individual work
with specially trained coaches. For this reason, more significant differences are expected in
older category and in senior teams. On the other hand, early selection influenced taller
children to become goalkeepers. Their height is the advantage, bearing in mind specific
requirements and movements which are necessary for this position in team.
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Submitted April 5, 2012
Accepted June 15, 2012
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