Concentric Power Differences during Take-off
between Young Male and Female Team Handball Players
Igor Gruic
Faculty of Kinesiology, University of Zagreb, Horvacanski zavoj 15, Zagreb, Croatia
1 OBJECTIVES
Differentiating gender related manifestations of
power through two-legged taking-off kinetic chains
was main objective of this research.
Basic techniques of exertion of power while
jumping in team handball have major impact on
individual and group tactics efficiency. Potential
within individual player’s performance rise
proportionally with greater variability, versatility
and control of timing, intensity, function, structure
etc. of concentric, eccentric and elastic component
of muscular contraction. It is the case for individual
sports like athletics (Čoh et al., 2013.), or
gymnastics (Medved et al., 1995), therefore those
are functionally reflected in specific take-off,
throwing/shooting and sprinting techniques in team
sports.
Hypothesis of this research was that from certain
age arising gender related differences in observed
characteristics are measurable by the height of jump,
but by average concentric power as well.
2 METHODS
Participants were 41 young team handball player (24
male and 17 female) 16±1 yr., all member of
national selection preparing for international
tournaments (European Championships) in year
2006/7.
Tensiometric Platform (Kistler factory) and
standard Quattro Jump protocol was used to collect
data (variables in table 1.) and to produce figures.
Concentric, eccentric and elastic component of
take–off were assessed trough Squat Jump (HSJ,
PSJ), Countermovement Jump (HCMJ, FI, PCMJ,
STR, FIBR), Continuous Jumps (HCJ, PCJ, KCJ)
(BW and DELTAH included in formulas).
Data was processed by statistical package
Statistica for Windows 5.0 (StatSoft, Inc.). Basic
measures of central tendency and dispersion,
Pearson product-moment correlation, and t-test for
independent samples were used to assess data, to
produce figures, and to test main hypothesis.
Table 1: Sample of Variables.
Symbol Designation Formula
HSJ
(cm)
Rise of center
of gravity
Maximum of s(t) during
flight time - Squat Jump
PSJ
(W/kg)
Average
concentric
power
Pavg = avg (P(t)) from the
time when v(t) becomes
positive until takeoff
HCMJ
(cm)
Rise of center
of gravity
Maximum of s(t) during
flight time –
Countermovement Jump
FI
(%bw)
Instantaneous
Force
Fi = F(ecc/con transition) -
Fbw
PCMJ
(W/kg)
Average
concentric
power
Pavg = avg (P(t)) from the
time when v(t) becomes
positive until takeoff
STR
(%)
Prestretch
benefits
Effect of Prestretch [%] =
(hf(CMJ) / hf(SJ) * 100%)
–100%
FIBR
(%FT)
Percentage Fast
Twitch Fibres
Proprietary algorithm of
Prof. Carmelo Bosco
(estimation)
HCJ
(cm)
Rise of center
of gravity
Maximum of s(t) during
flight time - Continuous
Jumps
PCJ
(W/kg)
Average
concentric
power
Pavg = avg (P(t)) from the
time when v(t) becomes
positive until take-off
KCJ
(kN/m)
Leg Pseudo
Stiffness
k = abs((Fi + BW) / delta h)
BW
(kg)
Body Weight Mass
DELTAH
(m)
Jump height
difference
s(jump start) – s(ecc/con
transition)
3 RESULTS
Within all processed signals (figure 1. – example:
best performance), descriptive statistics (table 2. –
Whole sample, male and female), and quadratic
diagram (figure 2 - results in Squat Jump presented
with results in Countermovement Jump and
Gruic I..
Concentric Power Differences during Take-off between Young Male and Female Team Handball Players.
Copyright
c
 2014 SCITEPRESS (Science and Technology Publications, Lda.)

Continuous Jumps.) reveal inconsistencies which
were objective of the analysis.
Figure 1: Signal for highest individual result (example:
HCMJ = 70.1 cm).
Table 2: Descriptive statistics; T-test of differences
between male and female subjects (t/p-values).
M±S
n=41
M(n=24
F(n=17) t p
HSJ
40,2±5,
8
43,5±4,
7
35,6±3,
7
5,7
6
0,0
0
PSJ
23,0±3,
0
23,3±2,
9
19,2±2,
2
3,7
5
0,0
0
HCM
J
53,2±7,
8
57,7±5,
7
46,7±5,
3
6,2
9
0,0
0
FI
0,97±0,
3
0,97±0,
2
0,97±0,
3
0,1
0
0,9
2
PCMJ 25,6±5
28,0±3,
7
22,3±4,
6
4,4
6
0,0
0
STR
33,1±8,
4
33,2±9,
1
33,0±7,
7
0,0
8
0,9
3
FIBR
36,2±9,
2
39,7±8,
6
31,2±7,
9
3,2
6
0,0
0
HCJ
39,5±6,
1
42±5,2 36±5,6
3,5
0
0,0
0
PCJ
41,6±6,
6
43,1±6,
4
39,5±6,
4
1,7
7
0,0
8
KCJ
22,3±7,
2
23±7,7
21,3±6,
4
0,7
2
0,4
7
Figure 2: Quadratic surface – results of HSJ vs. HCMJ vs.
HCJS.
Variables were distributed normally under
theoretical Gauss distribution (K-S d=0,07-0,13, p>
0.20). Correlations between rise of center of gravity
(in HSJ, HCMJ and HCJ) and average concentric
power (PCMJ, PCJ) were statistically significant in
range 0.52-0.83.
4 DISCUSSION
T-test (table 2.) confirmed hypothesis of existing
differences in average concentric power between
male and female subjects (PSJ: t=3,75, p<0,01;
PCMJ: t=4,46, p<0,01; and with lower level of
significance PCJ: t=1.77, p<0,08).
Indirectly, differences in concentric, eccentric
and elastic component of take–off were confirmed
with statistical significance in variables HSJ (t=5,76,
p<0,01), HCMJ (t=6,29, p<0,01), and HCJ (t=3,50,
p<0,01).
Although estimated by standard Bosco protocol,
observable statistically significant difference in
percentage of used fast twitching fibres FIBR
(t=3,26, p<0,01) go in line with previous results.
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