title: Reliability of two goniometric methods for measuring active subtalar range of motion.
abstract: BACKGROUND
  Measuring subtalar joint (STJ) motion is accompanied by complications due to the oblique STJ axis which results in triplanar pronation and supination.
  
  
  OBJECTIVE
  We developed a pronator and supinator testing apparatus whose axis was aligned with Inman's STJ axis. The purpose of this study was to assess day-to-day reliability of active STJ range of motion (ROM) measurements and to compare the results with those of a rearfoot goniometer.
  
  
  METHODS
  Active pronation, supination and total STJ ROM measurements were administered to 12 men (mean age: 23.8 years) and 12 women (mean age: 22.3 years) at two separate test sessions. Intraclass correlations (ICC), limits of agreement (LoA) and minimum detectable change (MDC) were calculated.
  
  
  RESULTS
  Except for pronation ROM in men, the STJ goniometer revealed substantial (ICC > 0.8) reliability in all conditions. Relative MDCs and LoAs were below 15% and 10%, respectively. Significantly higher total ROM (P< 0.05) was found for women compared to men when using the STJ goniometer. The rearfoot goniometer showed high reliability (ICCs > 0.7) but underestimated STJ ROM in average of 37%.
  
  
  CONCLUSIONS
  Both goniometric methods showed high day-to-day reliability. However, when using the rearfoot goniometer, researchers have to consider whether the level of underestimation of STJ motion is acceptable in the context of the planned investigation.
authors.affiliation: Biomechanics Laboratory, Department of Sport and Movement Sciences, University of Duisburg-Essen, Essen, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Hagen
authors.affiliation: Biomechanics Laboratory, Department of Sport and Movement Sciences, University of Duisburg-Essen, Essen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Lemke
authors.affiliation: Biomechanics Laboratory, Department of Sport and Movement Sciences, University of Duisburg-Essen, Essen, Germany.
authors.forename: Lena
authors.initials: L
authors.lastname: Paszota
authors.affiliation: Department of Orthopaedic Surgery, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Lahner
mesh_terms: D000328:Adult; D053587:Arthrometry, Articular / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D016059:Range of Motion, Articular / Q000502:physiology*; D015203:Reproducibility of Results; D012737:Sex Factors; D013380:Subtalar Joint / Q000502:physiology*
keywords: Range of motion; intraclass correlations; limits of agreement; minimum detectable change; pronation; subtalar joint axis; supination