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AGILITY IN YOUNG ATHLETES:ISITADIFFERENT
ABILITY FROM SPEED AND POWER?
YASSINE NEGRA,
1
HELMI CHAABENE,
2
MEHRE
´ZHAMMAMI,
1
SAMIHA AMARA,
3
SENDA SAMMOUD,
1
BESSEM MKAOUER,
3
AND YOUNE
´SHACHANA
1,2,3
1
Research Unit “Sport Performance and Health,” Higher Institute of Sport and Physical Education of Ksar Said, Tunis,
Tunisia;
2
Tunisian Research Laboratory “Sports Performance Optimization,” National Center of Medicine and Science in
Sports (CNMSS), Tunis, Tunisia; and
3
Higher Institute of Sports and Physical Education, Manouba University, Tunis, Tunisia
ABSTRACT
Negra, Y, Chaabene, H, Hammami, M, Amara, S, Sammoud, S,
Mkaouer, B, and Hachana, Y. Agility in young athletes: is it
a different ability from speed and power? J Strength Cond
Res 31(3): 727–735, 2017—Agility is an important physical
attribute for successful participation in team sports events.
Illinois agility test (IAT) and T-test have been widely used
within adult team sports players to assess agility perfor-
mance. The purposes of this investigation are (a) to study
the reliability and the sensitivity of both IAT and T-test scores
and (b) to explore to what extend the agility is an indepen-
dent physical ability from speed time and jumping ability.
Competitive-level young soccer (n= 95) and handball play-
ers (n= 92) participated in this study (i.e., approximately 12
years old). Reliability analyses were established by determin-
ing intraclass correlation coefficient (ICC
(3,1)
)andtypical
error of measurement (TEM). The sensitivity of agility tests
was revealed by comparing TEM to the value of the smallest
worthwhile change (SWC). The second aim was examined
by means of the principal component analysis. Results re-
vealed that the scores of both IAT and T-test showed a high
reliability (all ICC
(3,1)
.0.90 and TEM ,5%) and sensitivity
(all TEM ,SWC). Principal component analysis resulted in
one significant component for the soccer and handball
group each that explained 72.18 and 80.16% of the total
variance, respectively. Significant relationships were re-
corded between all the selected tests (r=20.72 to 0.85,
p,0.001). Based on the results of this study, it was con-
cluded that both IAT and T-test provided reliable and sensi-
tive scores. Therefore, these tests could be strongly
recommended to evaluate agility within young male
competitive-level team sports athletes. In addition, it seems
that agility, speed time, and jumping ability assess the same
physical attribute in young competitive-level team sports
players.
KEY WORDS reliability, sensitivity, team sport, sprint, principal
component analysis
INTRODUCTION
Agility is one of the most important aspects that
should be developed and routinely implemented
in strength and conditioning programs for team
sports athletes (4,25,30,37). Generally, agility is
defined as a rapid whole-body movement with change of
direction and/or velocity in response to a stimulus (30). Mirkov
et al. (21) reported that agility and coordination is one of the
crucial factors in future success in 11-year-old athletes. Hacha-
na et al. (11) and Pauole et al. (26) have identified the Illinois
agility test (IAT) and the agility T-test as 2 of the best tests to
measure agility, respectively. Although the existing researches
have shown the good validity and reliability of these tests
among junior-senior team sports athletes (13,29,31), this issue
remains unclear in young athletes considering the difference in
maturity status and/or chronological age in addition to the
training background between them (5). Furthermore, accord-
ing to Hachana et al. (10), the IATmight not represent a sport-
specific test for young players because of the long duration
(approximately 16–18 seconds) and the long distance covered
(approximately 60 m). Thus, this test might be overly strenuous
for young players, which might also affect its validity and/or
reliability. Therefore, further investigations in this area are
needed.
Limited scientific literature is available providing specific
details on how best to train agility for children (19,25). To
optimize agility training programs, correlation analysis with
other fitness variables (i.e., power, speed, strength.) needs to
be established. Pauole et al. (26) established a significant cor-
relation between T-test, leg power, and leg speed within male
college-aged men (coefficient of determination [R
2
] = 24 and
30%, respectively). Hachana et al. (11) revealed that IAT per-
formance is significantly related to speed (R
2
= 18%) rather
than to acceleration (R
2
= 2%), and leg power (R
2
=15%).In
contrast, Little and Williams (18) revealed that acceleration
Address correspondence to Dr. Yassine Negra, yassinenegra@hotmail.fr.
31(3)/727–735
Journal of Strength and Conditioning Research
Ó2016 National Strength and Conditioning Association
VOLUME 31 | NUMBER 3 | MARCH 2017 | 727
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(10-m sprint times), top speed (flying 20-m sprint times), and
agility were distinct motor characteristics in a group of pro-
fessional male soccer players. In the same context, Jefferys (15)
revealed that agility is an independent physical quality and
requires, therefore, specific training and testing protocols.
However, in an investigation conducted with young athletes,
LIyod et al. (19) revealed that the straight-line running speed,
lower limb strength and power, anthropometric variables, and
perceptual and decision-making processes could be some of
the important contributors to the agility outcomes.
Overall, based on the results presented above, it is clear
that some difficulties in identifying how agility performances
can be related to other fitness variables exist, therefore, this
issue needs to be resolved in future studies. This observation
seems to be due to various factors, such as training age,
athlete’s level, sex, and time in the training season that could
affect the level of correlation (3,8,12,33). In addition, it is
important to stress that there is a paucity of investigations
in this area that included young participants. In view of the
fact about the existing anatomical, biomechanical, and neu-
romuscular differences between adult and young athletes
(32), the question concerning the relationships between var-
ious motor skills, such as speed time, jumping ability, and
agility performance within young team sports players re-
mains unclear.
Based on the above-mentioned considerations, the aims of
the current investigation were (a) to establish the reliability
and sensitivity of both IAT and T-test in a sample of 2 different
young team sport athletes (i.e., soccer and handball) and (b) to
explore to what extend the agility is an independent physical
ability from speed time and jumping ability. It was hypoth-
esized that IAT and T-test would provide stable test-retest
scores. We hypothesized, also, that agility, sprint time, and
jumping ability represent dependent fitness abilities.
METHODS
Experimental Approach to the Problem
Young athletes are widely involved in soccer and handball
practice around the world. It has been well acknowledged
that agility is an essential physical ability in soccer and
handball games where rapid movement initiation, change of
direction, and fast short distance running are determinant for
successful participation in such team sports events (10,28).
The IAT and the T-test were frequently used as the most
common protocol for testing agility. However, those tests
lack information about their reliability and sensitivity among
young male team sports athletes. In addition, sprint time and
jumping ability are hypothesized to be a major factor con-
tributing to agility performance. Although agility’s basis can
be explained scientifically, the effectiveness of various agility
training interventions is still problematic. For this purpose,
the subjects participating in this cross-sectional study took
different power (vertical/horizontal jumps), speed (10 and
20 m), and agility (IAT and T-test) assessments. Statistical
analysis was conducted to assess the reliability of agility tests
(i.e., IAT and T-test). In addition, principal component anal-
ysis (PCA) was applied to evaluate the factorial analysis of all
the aforementioned tests.
Subjects
One hundred eighty-seven competitive-level male young
athletes (n= 187), who are regularly involved in national first
division events, participated to this investigation (soccer players:
n= 95, age = 12.27 60.91 years, predicted age at peak height
velocity = 11.07 60.91, body mass = 43.2 67.9 kg, height =
152.5 69.6 cm, sitting height = 74.70 64.47 cm and handball
players: n= 92, age = 12.51 61.69 years, predicted age at peak
height velocity = 11.66 61.69 years, body mass = 52.5 617. 2
kg, height = 158.3 622.1 cm, sitting height = 77.85 66.38 cm).
They had an experience of at least 4 years at their respective
competitive level. Both groups participated in a regular training
program (5 sessions per week) over the entire season. Both
group trainings included training in fast footwork, technical
skills, and moves (easy/difficult), as well as position games
(small/big), and tactical games with various objectives.
All participants were thoroughly informed regarding the
purpose and the potential risks of the study and were
informed that they can freely withdraw from the study at
any time of the experience. In accordance with the 1975
Declaration of Helsinki, the human subject committee of the
local institution approved this investigation. Before starting
the experience, an informed consent was signed by both the
participants and their parents.
Procedures
This study was conducted during the second half of the
competitive season (March–April 2014). The first phase of
this study aimed to establish the reliability and the sensitivity
of both the IAT and the T-test. During this phase, each
athlete completed the IAT and the T-test twice on separate
days. On each day, the aforementioned agility tests were
performed in triplicate. The best trial was retained for statis-
tical analyses. A minimum of 3 minutes of rest was allocated
between trials and 5 minutes between tests (33). In the sec-
ond phase, we analyzed the relationship between the IAT,
T-test, speed time, and jumping ability. Tests were performed
in triplicate and the best trial was retained for statistical
analyses. The same recovery duration between tests and
trials as during the first phase was adopted. All the players
undertook 3 familiarization sessions of all tests, within the 2
weeks preceding the experience. During the familiarization
session, each subject performed the IAT, followed by the
T-test, jumping tests, and sprint test. To avoid the diurnal
variation, all tests were completed at the same time of day
(i.e., 9–11 AM) in the absence of wind and in environmental
conditions of 21–238C for temperature and 51–55% for
humidity on a wooden indoor floor surface. The participants
were instructed to maintain consistent dietary and sleeping
patterns for 48 hours before each session and to refrain from
strenuous activity for 24 hours before each session. They were
also instructed to wear the same footwear during all sessions.
Evaluation of Agility on Young Team Sports Athletes
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The 2 testing phases of the study were preceded by
15 minutes standardized warm-up followed by 5 minutes
passive recovery period. The test-retest sessions were
separated by at least 72 hours. All procedures for each test
were administered by the same experimenter.
Anthropometry and Somatic Development. All anthropometric
measurements were conducted by the same researcher. The
following anthropometric measurements were taken: height
and sitting height (accuracy of 0.1 cm; Hotain, United
Kingdom) and body mass (0.1 kg; Tanita BF683W, Munich,
Germany). During all measurements procedures, partici-
pants were barefoot and dressed in shorts only. Maturity age
was determined according to peak height velocity, (maturity
offset = 27.999994 + [0.0036124 3age 3height]; R
2
=
0.896; standard error of estimate [SEE] = 0.542) (22).
Illinois Agility Test. The IAT performance was recorded using
an electronic timing system (Microgate SARL, Bolzano,
Italy). The test is set up with 4 cones used to mark the start
and 2 turning points, whereas another 4 cones were placed
down toward the start line at equal 3.3 m distance apart. The
cone’s height was 30 cm. The subject would sprint 10 m,
turn and return back to the start line, and then he would
swerve in and out of 4 markers, completing the test with two
10-m sprints in opposite direction (1). The players were in-
structed not to cut over the markers, but to run around them.
If a subject failed to do this, the trial was stopped repeated
after the standard recovery period.
Agility T-Test. This test was administered using the protocol
outlined by Munro and Herrington (23). Subjects started
with both feet behind the starting line. Four cones were
arranged in a T shape, with a cone placed 9.14 m from the
starting cone and 2 further cones placed 4.57 m on either
side of the second cone. Each subject accelerated to a cone
and touched the base of the cone with the right hand. Facing
forward and without crossing feet, subjects had to shuffle to
the left to the next cone and touch its base with the left hand,
then shuffle to the right to the next cone and touch its base
with the right hand and shuffle back to the left to the last
cone and touch its base. The cones height was 30 cm.
Finally, subjects ran backwards as quickly as possible to re-
turn to the starting/finish line. The test had to be repeated if
athletes crossed 1 foot in front of the other, failed to touch
the base of the cone, and/or failed to face forward through-
out the test. The time needed to complete the test was used
as performance outcome and it was assessed with an elec-
tronic timing system (Microgate SARL).
Squat Jump. The participant started from a stationary semi-
squatted position (knee angle = 908) with their hands on the
iliac crest jumped upward as high as possible. Squat jump
performances were recorded through an Optojump photo-
electric cell (Microgate SRL). The intraclass correlation
coefficient (ICC)
(3,1)
for test-retest trials was 0.96.
Countermovement Jump and Countermovement Jump–Aided
Arm. Participant started from an upright standing position
and performed a very fast preliminary downward movement,
flexing his knees (at approximately 908) and hip. Immediately
after that, he extended the knees and hips again to jump ver-
tically off the ground. To avoid the influence of the upper
limbs on countermovement jump (CMJ) performance, partic-
ipants kept their hands on the iliac crest. During countermove-
ment jump–aided arm (CMJA), the players freely used their
hands while jumping CMJ, and CMJA performances were
recorded through an Optojump photoelectric cell (Microgate
SRL). The ICCs
(3,1)
for test-retest trials was 0.94 and 0.93 for
CMJ, and CMJA, respectively.
Five Jump Test. This test has previously been recommended
for the measurement of lower limb muscle power and is
considered to be soccer specific (9). From an upright stand-
ing position with both feet flat on the ground, participants
tried to cover as much distance as possible with 5 forward
jumps by alternating left- and right-leg ground contacts. The
TABLE 1. Subject physical characteristics.*†
Soccer players
(n= 95)
Handball players
(n= 92) Cohen’s d
95% CI of the
difference
Age (y) 12.27 60.91 12.51 61.69 20.18 20.1486 to 0.6308
Height (cm) 152.53 69.65 158.29 622.14 20.36 0.8631 to 10.6636
Weight (kg) 43.24 67.89 52.53 617.23z20.74 5.4502 to 13.1412
Sitting height (cm) 74.70 64.47 77.85 66.38 20.58 24.7310 to 21.5624
PAPHV (y) 11.07 60.91 11.66 61.69 20.45 20.2808 to 0.4986
*PAPHV = predicted age at peak height velocity.
†Data are presented as mean 6SD.
zSignificant difference between group p#0.05.
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TABLE 2. Descriptive data of agility, power, and sprinting performances (mean 6SD).*
IAT (s) T-test (s)
10-m
sprint (s)
20-m
sprint (s) CMJ (cm) SJ (cm) CMJA (cm) FJT (m)
Soccer players
(n= 95)
17.70†60.85 11.90†60.80 2.08†60.13 3.63†60.25 23.57 65.03 21.38 65.20 26.98 65.59 8.87 60.95
Handball players
(n= 92)
18.99 61.34 12.89 61.34 2.15 60.18 3.74 60.33 23.06 66.67 21.09 66.16 26.98 67.96 8.75 61.45
ES (Cohen’s d)
95% CI
21.18 (21.6
to 20.96)
20.92 (21.39
to 20.76)
20.45 (20.11
to 20.2)
21.31 (20.19
to 20.2)
0.08 (21.18
to 2.21)
0.05 (21.35
to 1.93)
0(21.97
to 1.98)
0(
20.22
to 0.47)
*IAT = Illinois agility test; T-test = agility T-test; CMJ = countermovement jump; SJ = squat jump; CMJA = countermovement jump–aided arms; FJT = five jump test; ES = effect
size.
†Denotes significant differences between soccer and handball players (p,0.01).
TABLE 3. Performance and reliability of the Illinois agility test and T-test in soccer and handball players.*
Test Trial 1 Trial 2 ICC
(3,1)
pTEM (s) TEM% MDC (s) SWC (s) MDC%
Soccer players (n= 95) IAT (s) 18.01 60.87 18.02 60.89 0.96 (0.94–0.98); ,0.00 0.82 0.16 0.89 0.44 0.17 2.47
T-test (s) 12.29 60.75 12.28 60.75 0.98 (0.96–0.98); ,0.00 0.66 0.10 0.85 0.29 0.15 2.36
Handball players (n= 92) IAT (s) 18.44 60.88 18.41 60.87 0.99 (0.98–0.99); ,0.00 0.24 0.10 0.50 0.26 0.17 1.39
T-test (s) 12.34 60.81 12.29 60.83 0.98 (0.95–0.98); ,0.00 0.14 0.12 0.99 0.34 0.16 2.76
*ICC = intraclass correlation coefficient; p= significance level; TEM = typical error of measurement; MDC = minimal detectable change; SWC = smallest worthwhile change; IAT
= Illinois agility test; T-test = agility T-test.
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TABLE 4. Correlations (with 95% CI) between sprint test, jump tests, the Illinois agility test, and T-test.*
10-m 20-m CMJ SJ CMJA FJT T-test
Soccer players (n= 95)
IAT
r0.66 0.57 20.67 20.64 20.61 20.71 0.66
95% CI 0.52–0.76 0.42–0.7 20.77 to 20.54 20.74 to 20.50 20.72 to 20.46 20.8 to 20.6 0.53 to 0.76
p0.001 0.001 0.001 0.001 0.001 0.001 0.001
R
2
0.44 0.33 0.45 0.41 0.37 0.50 0.44
T-test
r0.61 0.53 20.58 20.53 20.61 20.61
95% CI 0.48–0.73 0.37–0.66 20.7 to 20.43 20.66 to 20.37 20.72 to 20.47 20.73 to 20.47
p0.001 0.001 0.001 0.001 0.001 0.001
R
2
0.37 0.28 0.34 0.28 0.37 0.37
Handball players (n= 92)
IAT
r0.8 0.83 20.58 20.47 20.6 20.72 0.85
95% CI 0.71–0.86 0.75–0.88 20.7 to 20.42 20.61 to 20.29 20.71 to 20.44 20.81 to 20.6 0.78 to 0.90
p0.001 0.001 0.001 0.001 0.001 0.001 0.001
R
2
0.64 0.69 0.34 0.22 0.36 0.52 0.72
T-test
r0.82 0.85 20.69 20.60 20.7 20.80
95% CI 0.74–0.88 0.78–0.90 20.78 to 20.56 20.71 to 20.45 20.80 to 20.60 20.86 to 20.70
p0.001 0.001 0.001 0.001 0.001 0.001
R
2
0.67 0.72 0.48 0.36 0.49 0.64
*CMJ = countermovement jump; SJ = squat jump; CMJA = countermovement jump–aided arm; FJT = five jump test; T-test = agility T-test; IAT = Illinois agility test; r= Pearson
correlation coefficient; p= significance level; R
2
= coefficients of determination.
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covered distance was measured to the nearest 1-cm using
a tape measure. The ICC
(3,1)
for test-retest trials was 0.94.
Sprint Testing. Linear sprinting was evaluated over 10 and
20 m using an electronic timing system (Microgate SARL).
Participants started 0.3-m before the first infrared photo-
electric gate, which was placed 0.75-m above the ground to
ensure a capture of the trunk movement and avoid false
signals through limb motion. The ICCs
(3,1)
for test-retest
trials was 0.96, and 0.95 for 10-, and 20-m, respectively.
Statistical Analyses
Data analyses were performed using SPSS 19.0 program for
Windows (SPSS, Inc, Chicago, IL, USA). Descriptive statistics
were generated for all variables. The significance level
considered in this study was set at p#0.05. The results are
expressed as mean 6SD. An independent samples t-test was
applied to determine significant differences in all performan-
ces and anthropometric values between groups. The effect
sizes (ES) is a measure of the effectiveness of a treatment,
and it helps to determine whether a statistically significant
difference is, really, a difference of practical concern. It was
determined according to Cohen’s dand classified as small
(0.00 #d#0.49), medium (0.50 #d#0.79), and large
(d$0.80) (7). Relative reliability was determined by calculat-
ing the ICC
(3,1)
. We considered an ICC below 0.40 as poor,
between 0.40 and ,0.70 as fair, between 0.70 and ,0.90 as
good, and $0.90 as excellent (7). Absolute reliability was ana-
lyzed through the typical error of measurement (TEM). It was
calculated by dividing the SD of the difference between scores
by
ffiffiffi
2
p(6,13) and expressed as coefficient of variation. The
smallest worthwhile change (SWC) has been used and calcu-
lated as 0.2 3SD. By comparing SWC with TEM score, test
sensitivity in detecting systematic variation in performance
status can be determined (6). When TEM ,SWC, the test’s
capacity to detect change is considered “good”; when TEM =
SWC, it is considered “ok,” and when TEM .SWC, the test
is rated as “marginal” (17). Pairwise comparisons were applied
to determine any learning effect or systematic bias between
sample mean scores for test and retest with paired student
t-test. The TEM allows the calculation of the minimal detect-
able change at the 95% CI (MDC
95
) according to the follow-
ing formula: MDC
95
=TEM3
ffiffiffi
2
p31.96 (16). The MDC
95
determines the minimum amount of change in the measure-
ment that would be required to exceed the level of measure-
ment error and was expressed in absolute and relative term for
comparison between agility tests. Pearson’s correlation was
used to determine relationships between, IAT, T-test, jumping
ability, and speed time performances. Coefficients of determi-
nation (R
2
) were used to determine the amount of explained
variance between tests. Hopkins (14) has suggested that an
absolute correlation coefficient of 0–0.1 is considered “trivial,”
one of 0.11–0.33 “small,” 0.31–0.5 = “moderate,” 0.51–0.7 =
“large,” 0.71–0.9 = “very large,” 0.9–0.99 = nearly perfect,” 1 =
“perfect.” The corresponding intercorrelation matrix of all
selected variables was factorized using the PCA (24). The
number of significant components was determined by the
Promax criterion with Kaiser normalization (24), which re-
tains principal components with eigenvalues of 1.0 or higher.
The final outcomes of the PCA were commonalities and fac-
tor loadings for each manifest variable, eigenvalues, and per-
centages of variance explained by each rotated principal
component.
RESULTS
In general, for both groups the biological age was determined
and revealing no significative difference between groups (t=
20.551, df =185,p= 0.582, ES = 20.26) (Table1).
All performance measures were mentioned in Table 2.
Reliability and
Sensitivity Analyses
The results of the IAT and T-
test obtained from the test and
retest are presented in Table 3.
The data suggest exceptionally
high reliability of both IAT and
T-test in the whole team sports
group (i.e., soccer and hand-
ball). Specifically, all ICC
(3,1)
values were well above 0.90,
whereas TEM values were
about 0.2 seconds (,5%). Based
on the sensitivity analysis, the
ability to detect small perfor-
mance change can be rated as
“good” in both competitive-
level young team sports players
(SWC .TEM).
TABLE 5. Results of principal component factor analysis.*
Soccer group, Factor loadings Handball group, Factor loadings
1 Communalities 1 Communalities
IAT 20.81 0.65 20.81 0.66
T-test 20.75 0.56 20.88 0.78
10-m sprint 20.89 0.74 20.93 0.86
20-m sprint 20.78 0.61 20.95 0.91
FJT 0.85 0.72 20.91 0.83
CMJ 0.93 0.87 20.91 0.82
SJ 0.89 0.79 20.84 0.71
CMJA 0.91 0.82 20.91 0.84
Eigen value 5.77 6.41
% of variance 72.18 80.16
*IAT = Illinois agility test; T-test = agility T-test; FJT = five jump test; CMJ = countermove-
ment jump; SJ = squat jump; CMJA = countermovement jump–aided arms.
Evaluation of Agility on Young Team Sports Athletes
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Relationship of Agility Outcomes With Speed and
Power Tests
The correlations and the corresponding 95% CI between the
2 agility tests and all the other jumping ability and sprinting
tests are shown in Table 4.
Significant relationships judged between large to very
large were recorded between all tests (r=20.72 to 0.85, p,
0.001). The highest correlations obtained were among the
IAT and the five jump test (FJT) (R
2
= 50.4%), and the T-test
and the 20-m sprint test (R
2
= 72%) in soccer and handball
group, respectively.
The PCA of our outcomes resulted in a single significant
component that explained 72.18 and 80.16% of the total
variance of all tests within soccer and handball group,
respectively. Correlation coefficients of all tests with the
extracted component were large to very large in both groups
and varied between 20.95 to 0.93 (Table 5). The highest
correlation with extracted factor was shown by the CMJ test
(r= 0.93) and by the 20-m sprint test (r=20.95), in soccer
and handball group, respectively.
DISCUSSION
The purposes of this study were to analyze the reliability and
the sensitivity, of both IAT and T-test among competitive-
level young team sports athletes and to determine to what
extend the agility is an independent physical ability from
speed time and jumping ability performance. The main
findings of this study are that (1) both IAT and T-test scores
were highly reliable (i.e., stable test-retest outcome) and sen-
sitive (i.e., able to detect small changes in performance) and
(2) the agility performance, speed time, and jumping ability,
could represent the same motor abilities in competitive-level
young male team sports athletes.
The IAT and the T-test differ in the generic cues
incorporated in their movement patterns (i.e., for the T-test,
the change of direction is preceded by shuffling movements,
which are absent in the IAT) and also differ in their energetic
requirements (i.e., the duration and the number of change of
direction differ between these 2 agility tests). All these
considerations might affect the reliability of these 2 tests,
as well as their relationship to jumping ability and speed time
performances.
Previous researchers have found a good reliability of the
scores obtained from both IAT and T-test among adult
athletes (11,20,26,29,30). In these studies, the ICC
(3,1)
across
2 trials reliability analyses exceeded 0.90. Pauole et al. (26),
Munro and Herrington (23), and Sporis et al. (31) reported an
ICC of 0.98, 0.82, and 0.92, respectively, for the T-test meas-
ures in male and female athletes aged between 19.1 60.6 and
22.3 64 years old. Hachana et al. (11) and Lockie et al. (20)
reported an ICC of 0.97 and 0.91 for the IAT score in young
Tunisian soccer players (aged 20.82 61.31 years old) and
Australian football players (aged 23.83 .37.04 years old),
respectively. In our study, relative reliability can be rated as
excellent for IAT and T-test scores (Table 3). Handball and
soccer players showed a higher ICC
(3,1)
than the previously
cited studies (between 0.96 and 0.98) (Table 3). These findings
may be explained by the fact that most of the athletes who
took part in our study were highly competitive team sports
athletes trained for agility skills and generated stable agility
skills during the tests. To obtain the within-subject variability
that would typically occur in the routine administration of the
assessment, the TEM was calculated. Typical error of mea-
surement values relative to the T-test and IAT within the 2
team sports athletes were very low (0.10–0.16 seconds) sup-
porting the good reliability of the scores obtained from these
tests. Our results are in accordance with those of Hachana
et al. (11) with a TEM of 0.19 seconds for the IAT outcome
and with those of Munro and Herrington (23) who found
a TEM of 0.17 seconds for the T-test score. These results
support the high reliability of both IAT and T-test outcomes
regardless of the team sports group and strongly recommend
coaches and conditioning trainers to use them as in adults,
with young team sports athletes.
Considering the sensitivity analysis, a comparison
between the TEM values and the SWC values for both tests
has been conducted (10,20). The results revealed that the
ability to detect small performance change can be rated as
“good” in both competitive-level young team sports players
because their SWC values were higher than their respective
TEM (Table 3).
In addition to the reproducibility of tests, those individuals
conducting tests must consider the issue of change and whether
observed differences actually reflect the true change. Further-
more, consideration of the MDC
95
is important to determine
the minimum amount of change in the measurement that
would be required to exceed the level of measurement error
(10,11).
In our study, the MDC
95
indicates that 95% of the as-
sessed athletes with the IAT and T-test will demonstrate
a random variation as a result of a measurement error of less
than 0.44 seconds (2.47%) and 0.34 seconds (2.76%), respec-
tively. Our results are in accordance with those of Hachana
et al. (10) (MDC
95
= 0.64 seconds) among elite and sub-elite
under 14-soccer players.
Our results revealed that agility performances and a variety
of field tests were correlated with each other within both
team sports group (Table 4).
In addition, our results showed a large to very large
significant relationships between agility performance and
sprinting tests (0.53 ,r,0.85, p,0.001; common variance
vary from 28 to 72%). This is in accordance with previously
published studies wherein moderate to large correlations
between straight sprinting tests and agility were observed (2,36).
In addition, jumping output recorded in our study
indicated a moderate to very large negative relationship
between jump tests and agility performances (20.47 ,r,
20.80, p,0.001; common variance vary from 0.22 to
0.64%) indicating that the greater is the explosive strength
performance, the lower is the time spent in the agility tests.
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This is not consistent with the findings of Young et al. (36)
who revealed a low relationship between CMJ and 20 m
change of direction test (r=20.10). Similarly, Webb and
Lander (34) reported a small and moderate correlation
between vertical and horizontal jumping and the L-run agil-
ity test (r=20.19 and 20.35, respectively). In addition,
Peterson et al. (27) reported a trivial to the small relationship
between the power output determined from a vertical jump
test and the agility T-test (rfrom 20.03 to 20.21). In addi-
tion to the differences in the methodology of power and
agility testing applied, we believe that this inconsistency is
due to the higher complexity of the agility tasks used in this
study compared with more simple motor skills like sprinting
and jumping. Consistently with the present results, the for-
mer authors revealed a significant correlation between hor-
izontal jump and the agility T-test (r=20.61). Interestingly,
agility was found to be most highly associated with horizon-
tal jumping performance than was vertical jumping out-
comes (Table 4). The similarity of the movement between
horizontal jump and agility seems to be one of the main
causes. Particularly, during the 5 jump test, subjects have
to exert muscle power in both eccentric and concentric con-
dition while maintaining the body balance.
In this study, results of the PCA revealed the extraction of
a single significant component that explained 72.18 and
80.16% of the total variance within soccer and handball
group, respectively. However, the exceptionally nearly
perfect correlation of the CMJ and CMJA revealed in the
soccer group with the extracted factor suggests that these 2
tests could have the highest factorial validity among all
evaluated tests. In addition, nearly perfect correlation
between the CMJ, CMJA, 10- and 20-m sprint test, and
FJT with the extracted factors was shown in the handball
group, supporting the commonality of these tests. Collec-
tively, the main finding of our study showed large to nearly
perfect correlations of all measures with the extracted
components (Table 5). This finding supports our research
hypotheses and the notion that the agility, jumping ability,
and speed time could represent the same motor abilities in
competitive-level young team sports athletes. To the greatest
extent, the aforementioned correlations among jumping,
sprinting, and Change of Direction Speed latent motor abil-
ities are in agreement with the results of the majority
(8,12,26,27,36) but not all (33,35,38) of the previous studies
based on correlation analysis.
To conclude, findings of the reliability and sensitivity
analysis strongly support the use of the T-test and the IAT in
the routine assessment of agility in young soccer and
handball players. In addition, the factorial analysis showed
a high proportion of commonalities between tests with the
extraction of only 1 factor. This finding implies that all tests
may measure the same physical attribute. Therefore, it may
be suggested using very few, if not only one of the evaluated
tests for use in the routine testing of young soccer and
handball players.
PRACTICAL APPLICATIONS
Strength and conditioning professionals use a multitude of
tests to measure performance factors such as strength, speed,
power, and agility. The results of such tests are used to gain
information that can be used to optimally train the athlete and
to predict athletic performance. Agility is one of the main
determinants of performance in team sports. The results of the
current research revealed that IAT and T-test provided reliable
and sensitive scores once 3 familiarization sessions proceed
testing. Therefore, IAT and T-test can be confidently used
with both soccer and handball young athletes to assess their
agility performance. The second finding of our research
strongly recommends that agility, speed time, and jumping
ability performances might be treated and tested as the same
motor abilities among competitive-level young male soccer
and handball players.
ACKNOWLEDGMENTS
The authors are pleased to thankfully acknowledge the
athletes and their trainers who willingly and patiently
contributed to this study. Also, the authors would like to
thank and express their gratitude to Dr. Slobodan Jaric for
the help.
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