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ISSN: 0301-4460 (print), 1464-5033 (electronic)
Ann Hum Biol, Early Online: 1–9
!2014 Informa UK Ltd. DOI: 10.3109/03014460.2014.926989
RESEARCH PAPER
Reference values of vertical jumping performances in healthy Tunisian
adolescent
Mohamed Tounsi
1,2
, Chirine Aouichaoui
2
, Mohamed Elloumi
2
, Mohamed Dogui
3
, Zouhair Tabka
4
, and
Yassine Trabelsi
1
1
Department of Physiology and Lung Function Testing, Faculty of Medicine Ibn-El-Jazzar, and
2
Department of Physiology and Lung Function
Testing, Faculty of Medicine of Sousse, University of Sousse, Sousse, Tunisia,
3
Department of Physiology and Lung Function Testing, Faculty of
Medicine of Monastir, Monastir, Tunisia, and
4
Laboratory of Physiology, Faculty of Medicine ‘Ibn El Jazzar’, Sousse, Tunisia
Abstract
Background: The assessment of normal values of muscle strength can be determined for the
health outcome of adolescents, especially those who are living in a developing country.
Aims: The purpose of this study is to identify the relationship between anthropometric variables
and vertical jumping performances. The jump height and the average of power were measured
to establish reference values of vertical jumping parameters in Tunisian healthy adolescents
aged 13–19 in both sexes.
Subjects and methods: Five hundred and twenty-five school adolescents (242 males and 283
females) were randomly selected to participate in this study. Maximum height and average of
power reached in countermovement jump and squat jump were provided by an Optojump
device. Full and stepwise regression models were used to identify which anthropometric
parameters significantly contributed to performance variables.
Results: All anthropometric parameters increased with age. Reference values and multiple
prediction equations of vertical jump parameters were set based on a large sample of healthy
Tunisian adolescents. The multiple regressions showed that age, mass, sitting height, waist size,
fat-free mass and leg muscle volume for boys and mass for girls were the best predictors of
jumping performances.
Conclusion: This study provides normative data for jumping performances in Tunisian healthy
adolescents aged 13–19 in both sexes. The percentiles values are calculated to estimate the
levels of adolescents with high or low jumping performances.
Keywords
Adolescent, growth, jump height, leg muscle
power, muscle volume
History
Received 10 February 2014
Accepted 13 May 2014
Published online 27 June 2014
Introduction
Adolescents are usually motivated to play games that require
short-duration high intensity efforts. These efforts involve
several motor tasks like jumping and throwing. These tasks
are generally used in school as an indicator of a specific
aspect of muscular strength (Malina et al., 2004; McGuigan &
Winchester, 2008).
Muscular strength can be defined as the maximal force or
tension that a muscle or a group of muscles could generate at
a specified velocity (Knuttgen & Kraemer, 1987). During and
after puberty, a marked increase in physical performance
occurs due to muscular, neuronal, hormonal and biomechan-
ical factors (Beunen & Malina, 1988). With puberty, on
average, boys become gradually larger in skeletal length and
width and in muscle size, but smaller in relative fat mass as
compared to girls (Seger & Thorstensson, 2000). In addition,
there is a general agreement that short-term exercise
performance increases during growth and maturation and it
is significantly higher in boys than girls during as well as after
the adolescent spurt (Dore
´et al., 2008; Temfemo et al., 2009;
Van Praagh & Dore, 2002). In this context, several studies
reported gender differences in jump height with higher
performances in boys compared to girls at puberty (Malina
et al., 2004). However, the observed jumping performance
changes remain questionable (Martin et al., 2004; Van Praagh
& Dore, 2002) since the relative contribution between
anthropometric parameters and physical performance during
growth in boys and girls were not investigated (Temfemo
et al., 2009).
There are a number of reference data published about
vertical jumping and leg power for English (Patterson &
Peterson, 2004) and Canadian (Payne et al., 2000) young
adults. Temfemo et al. (2009) have studied the relationship
between vertical jumping performance and anthropometric
characteristics for French students aged 11–16 years. Taylor
et al. (2010) have established a normative data for English
school children aged 10–15 years. Recently, a study has
presented a genders specific normative paediatric data report
about the reference data for jumping mechanography in
Correspondence: Dr. Mohamed Tounsi, Department of Physiology and
Lung Function Testing, Faculty of Medicine Ibn-El-Jazzar, University of
Sousse, Sousse, Tunisia. E-mail: m.tounsi@hotmail.fr
Ann Hum Biol Downloaded from informahealthcare.com by 41.225.214.102 on 07/02/14
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healthy Caucasian children and adolescents aged 6–18 years
(Sumnik et al., 2013). However, all of the mentioned studies
were conducted with European and north American subjects.
In the same context, the literature contains some reports of
differences in muscle strength, performance and power
between different ethnic groups (Holm et al., 2008;
Temfemo et al., 2009). It has been also shown that genetic,
environmental and anthropometric factors could influence
biological parameters among healthy Tunisian children and
adolescents (Sfar et al., 2009; Trabelsi et al., 2008). During
infancy and childhood, the development of motor competence
is dependent on and influenced by the growth and maturity
characteristics of the child (morphological, physiological and
neuromuscular). The environment in which a child is reared is
important since the motor development occurs in a specific
social context (Venetsanou et al., 2011).
Age, gender, morphological and metabolic factors have
been shown to be key determinants in maximal anaerobic
performance. Moreover, the ability to perform short-term
maximal exercise varies considerably between humans (Van
Praagh & Dore, 2002).
There is a paucity of work reporting the reference values of
vertical jumping in Tunisian children (Aouichaoui et al.,
2011) and there is a lack of data in adolescents. Up to now
there has been no vertical jumping and leg power normative
data for healthy Tunisian adolescents. Therefore, it is
important to have reference values relevant to the Tunisian
population.
The aims of the current study are to identify the
relationship between anthropometric parameters and vertical
jumping performances and to establish reference values of
vertical jump parameters among healthy Tunisian
adolescents.
Methods
Participants
Five hundred and twenty-five Tunisian healthy students (ages
ranging from 13–19 years) were enrolled for the study (242
males and 283 females). Students and their parents were fully
informed about the aims and procedures of the protocol and
signed a written informed consent form. The study protocol
was approved by the Tunisian Ministry of Education and the
Research Ethics Committee of Farhat Hached Hospital
(Sousse).
Adolescents were selected by a two-level cluster sampling.
First, they were randomly chosen from 14 Tunisian urban area
(410 000 inhabitants) and a rural area (510 000 inhabitants)
secondary schools (Tsimeas et al., 2005). They belonged to
several classes and had different age ranges (636 adolescents).
Then, each adolescent was interviewed for clinical assessment
and detailed medical history using a standard appropriate
questionnaire (Ferris, 1978). Questionnaire items were care-
fully explained in the local language. This provides descrip-
tive data about pathological muscle, history of respiratory,
neurological or cardiac disease, data concerning the student
home and family habits. On the basis of the questionnaire
responses, 64 adolescents from 636 were excluded.
Subsequently, vertical jump tests were performed by 572
students. Forty-seven students were unable to perform vertical
jump adequately and were also excluded. Finally, 525 healthy
adolescents (242 males and 283 females) were included in the
actual analysis.
Study design
Participants were familiarized with testing procedures prior to
actual measurements. The experimental design consisted of
anthropometric measurements and vertical jump testing. All
tests were completed in a school gymnasium under the
supervision of the investigators.
The experiment was conducted in February, March and
April 2012 in Tunisia. All sessions were carried out in the
afternoon (14:00–16:00 h) as time-of-day could affect short-
term maximal performance.
Anthropometric measurements
Mass was measured with a digital scale (Harpenden Balance
Scale, Holtain Ltd., Crosswell, UK) and standing and sitting
height were measured with an appropriate stadiometer
(Harpenden Portable Stadiometer, Holtain Ltd., Crosswell,
UK). Body mass index (BMI) was calculated as weight
divided by the square of the height. Leg length was measured
by an inextensible plastic tape from the uppermost part of the
iliac crest to the ipsilateral lowest part of the lateral malleus
(Kim et al., 2003). The waist size was measured around the
smallest part of the subject’s waistline (Aouichaoui et al.,
2011).
The measurements of skin-fold thickness were performed
on the left side of the body. Biceps, triceps, subscapular and
supra iliac skin-folds were measured in triplicate with a
Harpenden Skinfold Caliper (Holtain Ltd., Crosswell, UK)
and mean values were used for further analysis. The errors of
measurement were 0.1 mm and the reliability was 95%
(Moreno et al., 2003). Based on skin-fold thickness measure-
ments, percentage of fat mass (% fat) was calculated using
Siri’s formula (Durnin & Rahaman, 1967). Fat-free mass was
determined by subtracting fat mass from body weight
(Buskirk & Mendez, 1984).
Leg muscle volume was assessed using the anthropometric
method of Jones & Pearson (1969), with reference to the
techniques recommended by the International Biological
Programme (Weiner & Lourie, 1981). The leg is compared
to a truncated cone. This method has been validated for
youths (Johnston et al., 1988) as well as adults (Frisancho,
1981). The method is based on the summation of truncated
cones. With the subject standing erect and the feet slightly
apart, seven circumferences were taken with a metric tape at
pre-determined sites (Villac¸a et al., 2008). The heights above
the floor level for each circumference were obtained by using
a stadiometer. The gluteal furrow, one-third of the subischial
height up from the tibial–femoral joint space, the minimum
circumference above the knee, the maximum circumference
around the knee, the minimum circumference below the knee,
the maximum calf circumference and the minimum ankle
circumference are, respectively, the different circumferences
measured. The heights above the floor level for each
circumference were obtained by using a stadiometer. In
addition, anterior and posterior skin-fold thicknesses were
2M. Tounsi et al. Ann Hum Biol, Early Online: 1–9
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measured at the second circumference (thigh) and the sixth
circumference (calf) using a Harpenden caliper (Villac¸a et al.,
2008).
Vertical jump tests
Vertical jump was evaluated by the Squat Jump (SJ) and the
Countermovement jump (CMJ) tests. During the SJ, the subject
was instructed to sink and to hold a squat position for 3
seconds. On the count of three, he was requested to jump as
high as possible. A successful trial was one where there was no
sinking or countermovement prior to the execution of the jump.
The CMJ required the subject to be in a standing position and to
sink as quickly as possible until the knee was flexed
approximately to 90. He was then instructed to jump as high
as possible. Verbal encouragements were constantly given to
ensure high motivation. All subjects performed three trials for
each jump. The best of three attempts was retained. The jumps
were separated by a 2-minute rest to ensure sufficient recovery.
For vertical jump tests, participants were instructed to jump
vertically for maximal height and to land in the same position
and at the same place from takeoff to avoid lateral or horizontal
displacement (Yammauchi & Ishii, 2007). To emphasize the
use of leg extensors, participants were asked to maintain their
torso in an upright position (Bosco & Komi, 1980).
Jumping performance was evaluated with the optical
system (Optojump, Microgate, Italy). The apparatus com-
prises two bars placed 1 metre apart and parallel to each
other connected directly to a personal computer via a USB
port. The optical system transmits an infrared light 1–2 mm
above the floor. When the light is interrupted by the feet, the
units trigger a timer with a precision of 1 ms, which allows
the measurement of flight time and contact time. The unit
triggers a timer within 1 millisecond, which allows the
measurement of flight time and contact time.
The Power SJ and the Power CMJ involves each type of
jump during 15 seconds, which were also performed to
calculate the average of power output. The Power CMJ has
emerged as a consistent test in athletes as well as in
schoolboys in terms of testing the angular displacement of
the knee and the duration of the contact (Bosco et al., 1983;
Viitasalo et al., 1987)
The jump height (H), expressed in centimetres, was
calculated with the following formula: H ¼½ðT2
fgÞ=8. The
average of power (P), expressed in W/kg, was calculated with
the following formula: P¼½ðg2TfÞðTfþTcÞ=4nTc,
where gis the acceleration of 9.8 m
2
gravity; nis the
number of jump; Tfis the Flight Time expressed (s); and Tcis
the Contact time expressed (s).
Statistical analysis
All statistical procedures were performed using SPSS for
windows (version 17.0) and Eviews 7. Data were presented as
arithmetic means ± standard deviation (SD) and were
calculated for each variable. Data from males and females
were analysed separately. The normality of all anthropometric
and vertical jumping parameters was tested by Jarque-Bera
tests.
Comparisons between boys and girls at the same grade
were made using Student’s unpaired t-tests. Comparisons
between age groups (one group vs the precedent) were
analysed by one-way ANOVA.
When the ANOVA test was significant, a post-hoc
comparison analysis (Bonferroni) was used to determine
differences between all age groups. A multiple linear
regression analysis was used to determine the best predictors
of the dependent variable. A 0.05 probability level was used
for statistical significance. Percentile values were calculated
using statistical software XLSAT for windows version 2010.
Results
Anthropometric characteristics of healthy Tunisian
adolescents
Five hundred and twenty-five healthy Tunisian adolescents
(242 males and 283 females) were included in the present
study. Frequency distributions in both genders according to
age are shown in Figure 1.
The anthropometric characteristics according to age and
gender are presented in Table 1. For standing height, a
significant gender difference (p50.01) was found from 15
years onward, with higher values for boys. A significant
difference (p50.05) was shown in gender from 14–16 years
for weight. Girls and boys didn’t differ in waist size. For leg
length, a significant gender difference (p50.01) was recorded
from 14 years onward, with higher values for boys. BMI was
significantly different (p50.01) by gender only in 14 years.
Mass was significantly different by gender (p50.01), with
higher values for girls. Similarly, a significant difference
(p50.01) between boys and girls was observed in fat-free
mass from 14 years. For fat mass and percentage fat, a
significant gender difference (p50.01) was found from age
13–19, with higher values for girls.
Vertical jumping performances of healthy Tunisian
adolescents
Mean (±SD) vertical jumping performances recorded in
healthy Tunisian adolescents are shown in Table 2.
Boys and girls were statistically different in all vertical
jumping performance variables with higher values for boys.
For CMJ, gender difference was seen in power and jump
height at the age of 13 and 19 years. By age range, power was
Figure 1. Frequency distribution of healthy Tunisian adolescents
according to age and gender.
DOI: 10.3109/03014460.2014.926989 Vertical jumping performances in healthy Tunisian adolescents 3
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significantly different (p50.05) in boys. For SJ, boys and
girls were statistically different in power and jump height.
There were no significant differences between age classes.
Anthropometric parameters: Effect of age and gender
All anthropometric parameters increased with age as follows:
standing height (males: r
2
¼0.68, p50.01; females: r
2
¼0.38,
p50.01), mass (males: r
2
¼0.65, p50.01; females: r
2
¼0.48,
p50.01), sitting height (males: r
2
¼0.67, p50.01; females:
r
2
¼0.54, p50.01), waist size (males: r
2
¼0.44, p50.01;
females: r
2
¼0.42, p50.01), leg length (males: r
2
¼0.62,
p50.01; females: r
2
¼0.33, p50.01), fat-free mass (males:
r
2
¼0.71, p50.01; females: r
2
¼0.48, p50.01) and leg
muscle volume (males: r
2
¼0.57, p50.01; females:
r
2
¼0.37, p50.01).
Multiple regression equations of jumping perfor-
mances predicted in healthy Tunisian adolescents
The full-model multiple regression, along with stepwise
regression, examines the relative contribution of each inde-
pendent variable to each regression model (Table 3).
The analysis of multiple regressions with stepwise
regression showed that age, mass, sitting height, waist size,
fat-free mass and leg muscle volume for boys and mass for
girls were the best predictors of jumping performances
(Tables 4–6).
Table 1. Mean ± SD of anthropometr ic variables in healthy Tunisian adolescents by age and gender.
Age
Anthropometric characteristics Gender 13 14 15 16 17 18 19
Number Boys 29 28 33 32 52 31 37
Girls 36 24 25 33 63 57 45
Standing height (m) Boys 1.57 ± 0.07 1.60 ± 0.09
f
1.68 ± 0.07
a
1.71 ± 0.05 1.73 ± 0.06 1.75 ± 0.05 1.75 ± 0.05
Girls 1.53 ± 0.08
b
1.59 ± 0.05 1.55 ± 0.07
b
1.63 ± 0.0.07
b
1.64 ± 0.05
b
1.64 ± 005
b
1.65 ± 0.05
b
Mass (kg) Boys 43.1 ± 7.3 45 ± 7.2
e
56.73 ± 8.07
a,e
59.15 ± 7.47
e
63.04 ± 8.96 62.63 ± 7.23 66.6± 11.38
e
Girls 44 ± 6.91 52.78 ± 13.95 49.26 ± 0.06 53.77 ± 0.08 58.20 ± 0.07
b
56.90 ± 6.42
b
62.14 ± 9.11
Sitting height (m) Boys 0.74 ± 0.07 0.78 ± 0.05 0.82 ± 0.05
f
0.85 ± 0.04 0.87 ± 0.04 0.87 ± 0.02 0.87 ± 0.02
Girls 0.79 ± 0.04
b
0.82 ± 0.04
b
0.78 ± 0.04 0.84± 0.03 0.86 ± 0.03 0.87 ± 0.02 0.86 ± 0.02
Waist size (m) Boys 0.64 ± 0.05 0.68 ± 0.07 0.73 ± 0.05 0.72 ± 0.05 0.75 ± 0.07 0.73 ± 0.05 0.77 ± 0.08
Girls 0.62 ± 0.07 0.67 ± 0.1 0.66 ± 0.08 0.7 ± 0.06 0.72 ± 0.06 0.72 ± 0.06 0.72 ± 0.06
Leg length (m) Boys 0.92 ± 0.05 0.98 ± 0.06
f
1.02 ± 0.05 1.04± 0.04 1.05 ± 0.05 1.07 ± 0.05 1.06± 0.03
Girls 0.92 ± 0.04 0.92 ± 0.03
b
0.91 ± 0.05
b
0.94 ± 0.03
b
0.95 ± 0.04
b
0.96 ± 0.05
b,d
0.98 ± 0.04
b
Body mass index (kg/m
2
) Boys 18.27 ± 2.2 17.41 ± 1.56
b
20.03 ± 2.28
a
20.04 ± 2.16 20.80 ± 2.36 20.24 ± 1.93 21.4± 3.12
Girls 17.7 ± 2.04 20.8 ± 5.37 19.2 ± 2.01 20.1 ± 2.42 21.5 ± 2.53 21 ± 2.32 22.8 ± 3.08
%fat (%) Boys 19.26 ± 4.12 17.15 ± 4.56 19.16 ± 4.82 19.10 ± 4.18 15.99 ± 3.46 15.85 ± 3.64 17.91 ± 5.92
Girls 29.74 ± 2.27
b
31.06 ± 3.75
b
30.22 ± 1.52
b
31.76 ± 1.34
b
30.69 ± 1.95
b
29.91 ± 1.84
b
32.59 ± 3.63
b,c
Fat mass (kg) Boys 7.95 ± 1.65 7.89 ± 2.98 10.92 ± 3.98 11.79 ± 3.89 10.36 ± 3.32 10.02 ± 2.97 11.86 ± 4.92
Girls 13.16 ± 2.71
b
16.80 ± 6.34
b
15.42 ± 2.35
b
17.14 ± 3.2
b
17.89 ± 2.87
b
17.08 ± 2.59
b
20.38 ± 4.31
b,c
Fat-free mass (kg) Boys 35.2 ± 6.06 37.10 ± 5.14 45.95 ± 5.17
a
47.35 ± 4.69 52.67 ± 6.93
f
52.60 ± 5.45 54.19 ± 8.26
Girls 30.83 ± 6.42
b
35.97 ± 7.82 33.85 ± 4.25
b
36.62 ± 5.34
b
40.30 ± 5.43
b
39.82 ± 4.09
b
41.75 ± 5.69
b
Leg muscle volume (L) Boys 4.008 ± 0.778 4.557 ± 0.907 5.541 ± 0.749 6.088 ± 1.306 6.286 ± 1.278 6.283 ± 0.8
e
6.358 ± 1.267
Girls 4.3 ± 0.88 4.8 ± 1.06 4.9 ± 1.06 5.8 ± 1.1 6.046 ± 1.23 5.9 ± 1.1 6.23 ± 1.4
a
Boys: age vs previous age: p50.01.
b
Significant difference between boys and girls in the same age group (p50.01).
c
Girls: age vs previous age: p50.01.
d
Girls: age vs previous age: p50.05.
e
Significant difference between boys and girls in the same age group (p50.05).
f
Boys: age vs previous age: p50.05.
Table 2. Means (± standard deviation) for jumping performance in healthy Tunisian adolescents by age and gender.
Age
Jumping performance Gender 13 14 15 16 17 18 19
Number Boys 29 28 33 32 52 31 37
Girls 36 24 25 33 63 57 45
SJ height (m) Boys 0.18 ± 0.04
a
0.21 ± 0.05 0.23 ± 0.05 0.25 ± 0.02 0.26 ± 0.04 0.29 ± 0.05 0.28 ± 0.04
Girls 0.16 ± 2.98 0.15 ± 0.04
c
0.14 ± 0.02
c
0.15 ± 0.02
c
0.14 ± 0.03
c
0.15 ± 0.03
c
0.14 ± 0.02
c
SJ power (w/kg) Boys 10.16 ± 1.26
a
11.083 ± 1.424 11.743 ± 1.564 12.146 ± 1.093 12.445 ± 1.192 13.24 ± 1.349 13.11 ± 1.36
Girls 9.419 ± 0.492 9.192 ± 1.551
c
8.830 ± 0.859
c
9.372 ± 0.927
c
8.979 ± 0.971
c
9.265 ± 1.112
c
8.897 ± 0.951
c
CMJ height (m) Boys 0.19 ± 0.03
a
0.21 ± 0.05 0.23 ± 0.05 0.27 ± 0.02 0.28 ± 0.04 0.30 ± 0.04 0.29 ± 0.05
Girls 0.17 ± 0.03 0.15 ± 0.04
c
0.15 ± 0.02
c
0.16 ± 0.03
c
0.15 ± 0.03
c
0.16 ± 0.03
c
0.15 ± 0.03
c
CMJ power (w/kg) Boys 11.22 ± 1.408
a
11.36 ± 1.415 12.31 ± 1.665 13.47 ± 0.98
b
13.69 ± 1.324 14.05 ± 1.131 14.39 ± 1.449
Girls 10.505 ± 1.238 9.9677 ± 1.620
c
9.992 ± 1.038
c
9.968 ± 1.227
c
9.824 ± 1.243
c
10.022 ± 1.331
c
9.824 ± 1.200
c
CMJ, countermovement jump; SJ, squat jump.
a
Significant difference between boys and girls in the same age group (p50.05).
b
Boys: age vs previous age: p50.05.
c
Significant difference between boys and girls in the same age group (p50.01).
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Table 3. Full model multiple regression predicting jumping performance variablesy.
Vertical
jump Gender Constant
Age
coefficient
Mass
coefficient
Standing
height
coefficient
Sitting
height
coefficient
Waist
size
coefficient
Leg
length
coefficient
BMI
coefficient
Fat
free
mass
coefficient
Leg
muscle
volume
coefficient
Standard
error
of the
estimate R
2
p
Value
CMJ height Boys (n¼242) 47.865 0.382 1.385 0.673 0.149 0.289 0.224 0.676 0.623 0.138 4.449 48 0.459 50.05
Girls (n¼283) 25.345 0.061 1.620 0.510 0.088 0.244 0.046 0.982 0.174 0.153 3.210 06 0.123 50.05
CMJ power Boys (n¼242) 6.683 0.459 1.004 0.613 0.093 0.289 0.224 0.530 0.450 0.079 1.318 93 0.464 50.05
Girls (n¼283) 0.897 0.066 1.487 0.346 0.035 0.187 0.010 0.721 0.374 0.092 1.202 56 0.122 50.05
SJ height Boys (n¼242) 26.967 0.421 1.024 0.357 0.172 0.219 0.128 0.840 9.003 0.893 4.419 64 0.430 50.05
Girls (n¼283) 16.384 0.019 1.598 0.497 0.038 0.238 0.000 8.882 0.318 0.098 2.983 03 0.130 50.05
SJ Power Boys (n¼242) 3.842 0.413 0.873 0.520 0.169 0.232 0.239 0.418 0.310 0.188 1.264 31 0.404 50.05
Girls (n¼283) 3.054 0.037 1.875 0.643 0.019 0.191 0.063 1.061 0.343 0.994 0.937 76 0.132 50.05
SJ, squat jump; CMJ, countermovement jump.
yFunction: jump performance (power, jump height) ¼constant + (age coefficient age) + (weight coefficient weight) + (standing height coeffi-
cient standing height) + (sitting height coefficient sitting height) + (waist size coefficient waist size) + (leg length coefficient leg
length) + (BMI coefficient BMI) + (fat-free mass coeff icient fat-free mass) + (muscle volume coefficient muscle volume).
Table 4. Stepwise-model multiple regression predicting jump performance variablesy.
Vertical jump Gender Constant
Age
coefficient
Mass
coefficient
Sitting
height
coefficient
Waist
size
coefficient
Fat
free
mass
coefficient
Leg
muscle
volume
coefficient
Standard
error of
the estimate R
2
pValue
CMJ height Boys (n¼242) 0.943 0.369 0.433 0.142 0.253 0.723 – 4.485 92 0.440 50.05
Girls (n¼283) 24.049 – – – 0.281 – – 3.241 31 0.079 50.05
CMJ power Boys (n¼242) 7.318 0.447 – – 0.067 – 0.070 1.325 55 0.445 50.05
Girls (n¼283) 12.252 – 0.307 – – – – 1.203 46 0.095 50.05
SJ height Boys (n¼242) 2.887 0.413 0.537 0.169 0.199 0.696 – 4.403 67 0.424 50.05
Girls (n¼283) 23.237 – – – 0.310 – – 2.995 95 0.096 50.05
SJ power Boys (n¼242) 4.592 0.447 – 0.180 0.248 – 0.194 1.269 29 0.386 50.05
Girls (n¼283) 10.912 – 0.314 – – – – 0.941 83 0.099 50.05
SJ, squat jump; CMJ, countermovement jump.
yFunction: jump performance (power, jump height) ¼constant + (age coefficient age) + (weight coefficient weight) + (sitting height coeffi-
cient sitting height) + (waist size coefficient waist size) + (muscle volume coefficient muscle volume).
Table 5. Multiple regression equations predicting jump performance for boysy.
Vertical
jump
Depending
variable Constant
Age
coefficient
Mass
coefficient
Sitting
height
coefficient
Waist
size
coefficient
Fat free
mass
coefficient
Leg muscle
volume
coefficient
Standard
error of
the estimate R
2
pValue
CMJ Power 7.318 7.107 – – 4.521 4.431 – 1.325 55 0.445 50.05
CMJ height 0.943 0.369 0.433 0.142 0.253 0.723 – 4.485 92 0.440 50.05
SJ Power 4.592 0.447 – 0.180 0.248 – 0.194 1.269 29 0.386 50.05
SJ height 2.887 0.413 0.537 0.16 0.199 0.696 – 4.403 07 0.424 50.05
SJ, squat jump; CMJ, countermovement jump.
yFunction: jump performance (power, jump height) ¼constant + (age coefficient age) + (weight coefficient weight) + (sitting height coeffi-
cient sitting height) + (waist size coefficient waist size) + (fat free mass coefficient fat free mass) + (muscle volume coefficient muscle
volume).
Table 6. Multiple regression equations predicting jump performance for girlsy.
Vertical jump
Depending
variable Constant Mass coefficient
Standard error
of the estimate R
2
pValue
CMJ Power 12.252 0.37 1.203 46 0.095 50.05
CMJ height 21.363 0.271 3.251 36 0.073 50.05
SJ Power 10.912 0.314 0.941 83 0.099 50.05
SJ height 20.64 0.308 2.997 90 0.095 50.05
SJ, squat jump; CMJ, countermovement jump.
yFunction: jump performance (power, jump height)¼constant + (weight coefficient weight).
DOI: 10.3109/03014460.2014.926989 Vertical jumping performances in healthy Tunisian adolescents 5
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Percentiles
The 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles of
vertical jumping height and power are presented in Tables 7
and 8.
Discussion
The purposes of our study are to identify the relationship
between anthropometric parameters and height and power in
vertical jump and to establish normal values of vertical
jumping parameters in healthy Tunisian adolescents in both
genders.
The CMJ and SJ were chosen because they have been
found to be the most reliable in valid field tests for assessing
explosive power output of lower limbs (Markovic et al.,
2004). These measures could be a good means to establish
normal values of vertical jumping parameters in healthy
Tunisian adolescents in both genders.
Technical errors of measurement using an optical system
are possible (Bosquet et al., 2009). The system uses flight
time; thus, caution should be given to this method as it
requires a number of assumptions that might not hold (Hatze,
1998). Timing systems are not sensitive to several factors
known to affect the measure of jump and reach devices, such
as the accurate determination of the starting position height,
the shoulder range of motion or the correct timing and co-
ordination of the arm swing to ensure that the measurement is
recorded at the maximal height of the jump (Leard et al.,
2007).
Generally, our study showed a significant sex difference in
anthropometric characteristics. For standing height, we
reported higher values for boys from 15 years onward.
Similarly, Beenakker et al. (2001) reported differences
between boys and girls from 15 years onward. However,
Temfemo et al. (2009) found gender differences in
standing height from 13 years onward in French healthy
adolescents.
Concerning body mass, the statistical analysis revealed that
boys were heavier than girls from 14 years onwards. These
findings are partly in agreement with those of Beenakker et al.
(2001) and Temfemo et al. (2009), who found higher body
mass values in boys from 15 years onward.
Table 8. SJ power and CMJ power (w/kg) percentiles of boys and girls by age.
Boys Girls
Percentile 13 14 15 16 17 18 19 13 14 15 16 17 18 19
SJ power
5th 8.61 6.61 7.47 7.77 7.43 7.41 7.33 8.62 8.8 9.11 9.42 9.74 10.05 10.23
10th 8.8 7.17 7.82 8.07 7.83 7.81 7.69 8.05 8.31 8.76 9.23 9.70 10.15 10.41
25th 9.11 8.12 8.42 8.57 8.5 8.48 8.29 7.80 8.12 8.66 9.22 9.78 10.33 10.64
50th 9.43 9.11 9.04 9.1 9.19 9.18 8.91 7.63 7.98 8.57 9.18 9.8 10.39 10.74
75th 9.76 10.09 9.65 9.62 9.88 9.88 9.53 7.51 7.87 8.49 9.12 9.76 10.37 10.73
90th 10.07 11.05 10.25 10.13 10.55 10.56 10.14 7.46 7.82 8.44 9.08 9.72 10.33 10.7
95th 10.25 11.61 10.6 10.43 10.94 10.96 10.49 7.33 7.69 8.31 8.95 9.58 10.2 10.57
CMJ power
5th 8.93 8.85 10.01 11.26 11.95 12.01 12.03 8.45 7.34 8.16 8.11 7.65 7.87 7.84
10th 9.44 9.4 10.55 11.73 12.36 12.46 12.56 8.91 7.93 8.58 8.51 8.14 8.35 8.28
25th 10.32 10.35 11.46 12.52 13.07 13.22 13.46 9.7 8.93 9.29 9.21 8.99 9.17 9.04
50th 11.23 11.32 12.41 13.33 13.79 14.01 14.4 10.51 9.96 10.02 9.93 9.85 10.01 9.83
75th 12.13 12.29 13.36 14.15 14.52 14.8 15.33 11.32 10.99 10.75 10.65 10.72 10.85 10.61
90th 13.01 13.24 14.28 14.94 15.22 15.56 16.23 12.10 11.98 11.46 11.35 11.56 11.67 11.37
95th 13.53 13.79 14.82 15.41 15.63 16.01 16.76 12.56 12.57 11.88 11.76 12.05 12.15 11.82
Table 7. Vertical jump height (m) percentiles of boys and girls by age.
Boys Girls
Percentiles 13 14 15 16 17 18 19 13 14 15 16 17 18 19
SJ height
5th 0.11 0.12 0.16 0.2 0.21 0.2 0.21 0.11 0.12 0.14 0.16 0.18 0.2 0.21
10th 0.13 0.14 0.18 0.21 0.22 0.22 0.23 0.10 0.11 0.13 0.15 0.17 0.19 0.2
25th 0.15 0.17 0.21 0.23 0.24 0.25 0.25 0.11 0.12 0.13 0.15 0.17 0.19 0.2
50th 0.18 0.21 0.23 0.25 0.26 0.29 0.28 0.10 0.12 0.13 0.15 0.17 0.19 0.2
75th 0.21 0.24 0.26 0.26 0.28 0.32 0.31 0.10 0.11 0.13 0.15 0.17 0.19 0.2
90th 0.23 0.28 0.29 0.28 0.31 0.36 0.33 0.10 0.11 0.13 0.15 0.17 0.19 0.2
95th 0.25 0.3 0.3 0.29 0.32 0.38 0.35 0.10 0.11 0.13 0.15 0.17 0.19 0.2
CMJ height
5th 0.14 0.12 0.17 0.21 0.23 0.23 0.21 0.12 0.08 0.12 0.11 0.1 0.11 0.1
10th 0.15 0.14 0.18 0.22 0.24 0.24 0.23 0.13 0.1 0.12 0.12 0.11 0.12 0.11
25th 0.17 0.17 0.21 0.24 0.26 0.27 0.26 0.15 0.12 0.14 0.14 0.13 0.14 0.13
50th 0.19 0.21 0.24 0.26 0.29 0.3 0.29 0.17 0.15 0.15 0.15 0.15 0.16 0.15
75th 0.21 0.24 0.26 0.28 0.31 0.33 0.32 0.19 0.17 0.17 0.17 0.18 0.18 0.17
90th 0.23 0.28 0.29 0.3 0.33 0.35 0.35 0.21 0.2 0.18 0.19 0.2 0.2 0.19
95th 0.24 0.3 0.3 0.31 0.34 0.37 0.37 0.22 0.21 0.19 0.2 0.21 0.21 0.2
6M. Tounsi et al. Ann Hum Biol, Early Online: 1–9
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All anthropometric variables (standing and sitting height,
leg length, waist size, mass, BMI and fat-free mass) increased
significantly with age. This result could be explained by the
growth and maturity processes (Rogol et al., 2000).
The influence of the Growth Hormone (GH) and thyroid
hormones (T3 and T4) during the pre-pubertal period was
reported by Carabulea et al. (1980). During pubertal devel-
opment, interactions between GH, sex steroid hormones
(oestrogens and androgens) and production of insulin-like
growth factor I (IGF-I) lead to changes in body composition
and shape, including alterations in the relative proportions of
water, muscle, fat and bone (Rogol et al., 2000). Gender-
related changes in muscle mass have been largely attributed to
hormonal influences (Preece et al., 1984). However, GH, the
thyroid hormones, the somatomedins and insulin are known to
be important effectors in muscle growth (Florini et al., 1996).
The results showed that boys jumped higher than girls
from 13 years onwards. This result is consistent with recent
previous research. This difference by sex has been mentioned
in children (Bovet et al., 2007; Temfemo et al., 2009) and
adults (Patterson & Peterson, 2004). Taylor et al. (2010) also
showed that boys jumped significantly higher than girls from
11 years onwards. The gender difference in vertical jumping
performance might be due to changes in body composition
and, especially, an increase in %fat of muscle fibres, with the
increase in leg length and leg muscle volume which favoured
the boys from the age of 13 years onwards (Temfemo et al.,
2009). Also, Boye et al. (2002) showed that fat-free mass was
higher in favour of boys during the pre-pubertal and pubertal
periods.
Under the influence of testosterone, which is a potent
anabolic agent, boys have a significant increase in growth of
bone and muscle. The dramatic increase of testosterone levels
in boys between mid and late puberty may explain gender-
related difference. Besides, boys have a significant increase in
fat-free mass that exceeds the total gain in mass because of
the concomitant loss of adipose tissue (Tanner & Preece,
1989). Therefore, they jump higher than girls do owing to the
increase in their fat-free mass (Tanner & Preece, 1989).
Moreover, because of their significantly higher type IIb fibre
areas, boys seem to have a potential advantage compared with
girls during the adolescent period (Van Praagh & Dore, 2002).
The age group, type of jump and the method of recording
jump height were different from those used in other studies
(Bovet et al., 2007; Holm et al., 2008; Taylor et al., 2010).
The parameters measured in the study of Temfemo et al.
(2009) conducted with male and female French students aged
13–16 years showed higher values compared with our
findings. The average percentages of difference between the
two studies for SJ height were +58.1% in boys and +105.1%
in girls and higher values in CMJ height (+69.7% in boys and
+117.1% in girls). The study of Dore
´et al. (2008) showed
higher SJ height compared with those observed in our present
study (+45.1% in boys and +71.6% in girls aged 13–18
years).
Our data in vertical jump performances increased with age
in boys, whereas in girls tests tended to achieve a plateau or
even decline. These findings are consistent with those
reported in other studies (Malina et al., 1991) which reported
an increase in standing long jump performance for girls up to
the age of 12, followed by a plateau or even regression in
performance. However, for similar findings for 13–15 years
old, the research of Taylor et al. (2010), Dore
´et al. (2008) and
Klausen et al. (1989) reported a plateau after 12 years of age.
In the same context, Loko et al. (2000) reported vertical jump
data for 10–17 year old Estonian girls, which showed a
significant reduction in vertical height between 13 and 14
years of age.
The boys and girls jumped higher in the countermovement
jump than in the squat jump. It is well-established that
jumping, hopping, leaping and other bounding movements
can be improved by making a countermovement (Bobbert &
Casius, 2005). The greater height reached in the counter-
movement jump test could be explained by the active state
initiated during the preparatory countermovement. Whereas,
in the squat jump, the countermovement is inevitably
developed during the propulsion phase, so that the muscles
can produce more force and work during shortening (Bobbert
& Casius, 2005).
It has been previously demonstrated that neurological
factors influence jump performance (Taube et al., 2012).
Indeed, the stretch-shortening cycle is characterized by the
high complexity of the neural control. The efficiency of the
stretch-shortening cycle is dependent on the recoil properties
of the tendomuscular system, which can be inf luenced by the
central nervous system (Taube et al., 2012). Moreover,
developmental neurological changes might influence muscle
force which include the process of myelinization (Kraemer,
1989). Furthermore, it is well known that dynamic force of
the knee extensor muscles is one important factor limiting
performance in jumping exercises (Kums et al., 2005). The
increase of the co-ordination of synergists and antagonists
contributes to the increased ability to fully activate the
muscles (Sale, 1989). It is also likely that part of the muscle
force gain may be attributed to improved motor co-ordination.
Improved movement co-ordination is probably a more
important contributor to muscle force gains in more complex
multi-joint exercises. During puberty, the pyramidal system
attains full functional maturity and the individual becomes
capable of developing the fine co-ordinated movements based
on the integration of nervous activity from various levels of
the central nervous system and the impact from all peripheral
receptors (A
˚strand, 1992). Davies (1985) argued that object-
ive measurements of the muscle ability to generate force
should be independent of individual motivation.
A multiple linear regression analysis of vertical jumping
parameters including power and jump height as the dependent
variables and standing height, fat-free weight, age, sitting
height, waist size, leg length, body mass index, muscle
volume and weight as the independent variables was realized.
The choice of the appropriate multiple prediction equation
was made taking into account the highest coefficient of
determination (R
2
) over the range of ages and explains the
variation of the dependent variables (Tables 4 and 5).
The multiple regressions showed that age, weight, fat-free
weight, waist size, sitting height and leg muscle volume for
boys and the weight for girls were the best predictors of
jumping performances in adolescents.
In conclusion, this study provides prediction equations of
vertical jumping parameters in Tunisian healthy adolescents
DOI: 10.3109/03014460.2014.926989 Vertical jumping performances in healthy Tunisian adolescents 7
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based on a large cohort (n¼525) of adolescents aged between
13–19. These reference data are intended to assist clinicians
in assessment of muscle function and the screening and
detection of muscle weakness or to evaluate the possible
effects of therapy on adolescents suffering from any disorders
such as neuromuscular disease, mainly affecting leg muscle
power. Percentile was calculated to classify vertical jump
performance of this age group. It can be also used in sports to
identify talented athletes.
Declaration of interest
The authors report no conflicts of interest. The authors alone are
responsible for the content and writing of the paper.
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