title: Reliability of shoulder rotators isokinetic strength imbalance measured using the Biodex dynamometer.
abstract: BACKGROUND
  Isokinetic assessment of shoulder internal and external rotators is commonly used by clinicians to assess muscle performance and to guide rehabilitation. The reliability of isokinetic assessment is fundamental to track small but clinically relevant changes.
  
  
  OBJECTIVE
  We aimed to analyze the absolute and relative reliability of strength imbalance indices such as peak torque ratios (ERconc/IRconc, ERecc/IRecc, ERecc/IRcon, IRecc/ERcon), bilateral concentric and eccentric strength ratios, and to examine the reliability of external rotator and internal rotator peak torque measured using a Biodex(®) dynamometer in the seated position.
  
  
  METHODS
  Cross-sectional laboratory study.
  
  
  METHODS
  Forty-six healthy participants were tested twice with seven days between sessions, at 60°/s and 120°/s concentrically, and 30°/s eccentrically.
  
  
  RESULTS
  Low to moderate relative reliability (intraclass correlation coefficient: 0.25-0.81) was found for unilateral and bilateral strength imbalance ratios. High intraclass correlation coefficient values (0.87-0.97) were found for peak torque. Concerning absolute reliability, the standard error of measurement ranged from 9.1 to 25.6% for strength imbalance ratios and from 7.7 to 14.5% for peak torque measurements, and minimal detectable change ranged from 25.2 to 71% for strength imbalance ratios and from 21.3 to 40.2% for peak torque measurements.
  
  
  CONCLUSIONS
  The standard error of measurement and minimal detectable change reported in the present study should be taken into account when evaluating the individual longitudinal changes in clinical practice.
authors: Department of Physical Medicine and Rehabilitation, University Hospital of Saint-Etienne, Faculty of Medicine, Jean Monnet University, Saint-Etienne, France. Pascal.Edouard42@gmail.com
authors: Pascal
authors: P
authors: Edouard
authors: Philippe
authors: P
authors: Codine
authors: Pierre
authors: P
authors: Samozino
authors: Pierre-Louis
authors: PL
authors: Bernard
authors: Christian
authors: C
authors: Hérisson
authors: Vincent
authors: V
authors: Gremeaux
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D015203:Reproducibility of Results; D012782:Shoulder / Q000502:physiology*; D019415:Torque