Asymmetry of the Modified Illinois Change of Direction Test Impacts Young Elite Soccer Players' Performance.
BACKGROUND
The modified Illinois change of direction test (MICODT) is an asymmetrical test because the numbers of changes of direction performed to the right and to the left are unequal. Therefore, it is possible that the asymmetry of this test may influence agility performance testing.


OBJECTIVE
The aim of this study was to compare two opposite/mirrored versions of the modified Illinois change of direction test.


METHODS
Forty-six right-footed soccer players (17.2 ± 1.6 years-old) participated in the study. Players performed a modified Illinois change of direction test and a mirrored version of this test "inverted modified Illinois change of direction test" (I/MICODT) in a randomized and counter-balanced order. Paired t-test was used to determine whether significant differences existed between time performances of the tests as a within-subjects measure. Players were thereafter stratified into MICODT group or I/MICODT group according to their best performance and independent t-tests were used to determine differences between groups.


RESULTS
The analysis revealed no significant difference in time performance between the two versions of test as a within-subjects measure (P > 0.05, ES = 0.05). However, significant better time performances among inverted modified Illinois change of direction group (52% of players) were found when compared to the modified Illinois change of direction group (48% of players) (P < 0.04, ES = 0.66).


CONCLUSIONS
The modified Illinois change of direction test must be considered as an asymmetrical test because it underestimates more than half of the players' agility performances. Therefore, fitness coaches should take these results into account when using this test.
Tunisian Research Laboratory, Sport Performance Optimization, National Center of Medicine and Sciences in Sports, Tunis, Tunisia.
Mehdi
M
Rouissi
Laboratory of Exercise Physiology and Rehabilitation, Faculty of Sport Sciences, University of Picardie, Jules Verne, Amiens, France.
Moktar
M
Chtara
Laboratory of Exercise Physiology and Rehabilitation, Faculty of Sport Sciences, University of Picardie, Jules Verne, Amiens, France.
Ahmed
A
Berriri
Serviette Football Club, Geneva, Switzerland.
Adam
A
Owen
Athlete Health and Performance Research Centre, ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.
Karim
K
Chamari
Change of Direction; Leg Dominance; Soccer