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Fizička kultura
2017, vol. 71, iss. 2, pp. 99-110
article language: Serbian, English
document type: Original Scientific Paper

Creative Commons License 4.0
Intra-session and inter-session reliability of electromyography in leg extension during maximum voluntary isometric contractions of quadriceps: The effect of knee angle
aPolicija Abu Dabija, Odjeljenje za strateški menadžment i poboljšanje performansi, Ujedinjeni Arapski Emirati
bProfeks - Akademija zdravog života, Beograd
cUniversity of Belgrade, Faculty of Sports and Physical Education



Effects of the Applied Physical Activity to Locomotor, Metabolic, Psycho-Social and Educational Status of the Population of the Republic of Serbia (MESTD - 47015)
Application of biomedical engineering for preclinical and clinical practice (MESTD - 41007)


Numerous factors can influence the reliability of the signal obtained by electromyography EMG among which the type of contraction is practically fundamental. This study aimed to investigate intra- and inter-session reliability of EMG for maximal voluntary isometric contraction (MVIC) of the knee extensors at different joint angles. Nine healthy male students from the Faculty of Sport and Physical Education voluntarily joined the experiment. Main characteristics of the subjects were: age 23±1 years, body weight 80.8±7.8 kg and body height 182±7 cm. EMG signal from three surface heads of quadriceps femoris was recorded - vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF). Subjects had to perform 3 MVIC as fast as possible, as strong as possible at 6 different knee joint angles on 2 occasions separated by 7-8 days. The intra-class coefficient of correlation (ICC) was used to identify relative intra- and inter-session reliability, while standard error of measurement (SEM) was used to calculate the absolute reliability of each tested muscle. All muscles showed high intra-session reliability (ICC=0.488-0.988 and SEM=1.38-11.35). VL showed good inter-session reliability for most of the conditions (ICC=0.603-0.948), VM for two knee angles (ICC120°=0.764 and ICC130°=0.788), RF was not reliable for any knee angle. This study indicates that RF does not need to be used in EMG testing in leg extension MVIC due to lack of reliability between two sessions, and If EMG RMS from VL and VM will be tested, knee angle of 120° should be used for the testing.


testing; between-day; within-day; repeatability


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