title: Reliability of EMG power-spectrum and amplitude of the semitendinosus and biceps femoris muscles during ramp isometric contractions.
abstract: Appropriate reliability is a necessary condition for the use of surface EMG for evaluation of hamstring muscle function in cases of knee joint pathologies or ligament injuries. The aim of the study was to investigate the test-retest reliability of power spectrum and amplitude of surface electromyographic (EMG) measurements of semitendinosus (ST) and biceps femoris (BF) during ramp isometric contractions. Eleven males performed maximum isometric contractions (MVC) of the knee flexors in two sessions, a week apart with simultaneous recording of surface EMG of the BF and ST. Intra class correlation (ICC) and standard error measurements (SEM) were applied to assess test-retest reliability of the averaged EMG (aEMG) and the median frequency (MF) over 10 levels of force, from 0% to 100% of the maximum. The ICC values ranged from 0.38 to 0.96 for the aEMG with SEM values reaching 11.37% of MVC. For the MF, the ICCs ranged from 0.44 to 0.98 (SEM range 4.49-18.19Hz). In our set up, ramp contractions can be used to examine hamstring EMG patterns with acceptable reliability.
authors.affiliation: Laboratory of Neuromuscular Control and Therapeutic Exercise, Department of Physical Education and Sports Sciences at Serres, Aristotle University of Thessaloniki, Serres 62100, Greece. ekellis@phed-sr.auth.gr
authors.forename: Eleftherios
authors.initials: E
authors.lastname: Kellis
authors.forename: Athanasios
authors.initials: A
authors.lastname: Katis
mesh_terms: D000328:Adult; D004576:Electromyography / Q000295:instrumentation / Q000379:methods; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D007719:Knee Joint / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D012016:Reference Values; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted