title: Concurrent validity and reliability of the Simple Goniometer iPhone app compared with the Universal Goniometer.
abstract: OBJECTIVE
  The aim of this study was to assess the concurrent validity and reliability of the Simple Goniometer (SG) iPhone® app compared to the Universal Goniometer (UG).
  
  
  METHODS
  Within subject comparison design comparing the UG with the SG app.
  
  
  METHODS
  James Cook University, Townsville, Queensland, Australia.
  
  
  METHODS
  Thirty-six volunteer participants, with a mean age of 60.6 years (SD 6.2).
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Thirty-six participants performed three standing lunges during which the knee joint angle was measured with the SG app and the UG.
  
  
  RESULTS
  There were no significant differences in the measures of individual knee joint angles between the UG and the SG app. Pearson correlations of 0.96-0.98 and intraclass correlation coefficients of 0.97-0.99 (95% confidence interval: 0.95-1.00) were recorded for all measures. Using the Bland-Altman method, the standard error of the mean of the differences and the standard deviation of the mean of the differences were low.
  
  
  CONCLUSIONS
  The measurements from the SG iPhone® app were reliable and possessed concurrent validity for this sample and protocol when compared to the UG.
authors.affiliation: Department of Physiotherapy, James Cook University , Townsville, Queensland , Australia .
authors.forename: Anne
authors.initials: A
authors.lastname: Jones
authors.forename: Rebecca
authors.initials: R
authors.lastname: Sealey
authors.forename: Michael
authors.initials: M
authors.lastname: Crowe
authors.forename: Susan
authors.initials: S
authors.lastname: Gordon
mesh_terms: D000368:Aged; D053587:Arthrometry, Articular / Q000295:instrumentation* / Q000379:methods; D001696:Biomechanical Phenomena; D040421:Cell Phone; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D063731:Mobile Applications; D011237:Predictive Value of Tests; D011793:Queensland; D016059:Range of Motion, Articular; D015203:Reproducibility of Results
keywords: Goniometry; joint range; knee; measurement