title: The reliability of electromechanical delay and torque during isometric and concentric isokinetic contractions.
abstract: The purpose of this investigation was to examine the intra-subject reliability of electromechanical delay (EMD) and torque of the dominant and non-dominant elbow flexors during isometric and isokinetic muscle contractions repeated over five consecutive days. Eleven volunteers that were unfamiliar with isokinetic dynamometry participated in this study and were asked to attend the laboratory on five consecutive days. An isokinetic dynamometer was used to exercise the elbow flexors under isometric, slow (60 degrees s(-1)) and fast (210 degrees s(-1)) isokinetic conditions; surface electromyography was recorded from the belly of biceps brachii and the signal was synchronised with the dynamometer to determine EMD. Intra-subject reliability for all measures was good (CV range, 3.1-6.5%) with no discernable difference between the dominant and non-dominant arms during isometric and isokinetic conditions. In addition, there was little difference in EMD and torque variability between the dominant and non-dominant arms which may have applications for clinicians and future research design when monitoring and investigating human muscle function. These data provide researchers and clinicians with an indication of the magnitude of change that is required to elucidate the presence of a meaningful change to muscle function in the elbow flexors.
authors.affiliation: School of Human Sciences, St. Mary's University College, Twickenham, UK. howatsong@smuc.ac.uk
authors.forename: Glyn
authors.initials: G
authors.lastname: Howatson
authors.forename: Mark
authors.initials: M
authors.lastname: Glaister
authors.forename: James
authors.initials: J
authors.lastname: Brouner
authors.forename: Ken A
authors.initials: KA
authors.lastname: van Someren
mesh_terms: D000328:Adult; D005080:Exercise Test / Q000379:methods; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors; D019415:Torque