title: Reliability of moderate-intensity and vigorous physical activity stage of change measures for young adults.
abstract: BACKGROUND
  The purpose of this study was to examine the reliability of stage of change (SOC) measures for moderate-intensity and vigorous physical activity in two separate samples of young adults. Staging measures have focused on vigorous exercise, but current public health guidelines emphasize moderate-intensity activity.
  
  
  METHODS
  For college students in the USA (n=105) and in Australia (n=123), SOC was assessed separately on two occasions for moderate-intensity activity and for vigorous activity. Test-retest repeatability was determined, using Cohen's kappa coefficient.
  
  
  RESULTS
  In both samples, the reliability scores for the moderate-intensity physical activity staging measure were lower than the scores for the vigorous exercise staging measure. Weighted kappa values for the moderate-intensity staging measure were in the "fair to good" range for both studies (0.50 and 0.45); for the vigorous staging measure kappa values were "excellent" and "fair to good" (0.76 and 0.72).
  
  
  CONCLUSIONS
  There is a need to standardize and improve methods for staging moderate-intensity activity, given that such measures are used in public health interventions targeting HEPA (health-enhancing physical activity).
authors.affiliation: Cancer Prevention Research Centre, School of Population Health, University of Queensland, Herston, Australia. e.leslie@sph.uq.edu.au
authors.forename: E
authors.initials: E
authors.lastname: Leslie
authors.forename: M
authors.initials: M
authors.lastname: Johnson-Kozlow
authors.forename: J F
authors.initials: JF
authors.lastname: Sallis
authors.forename: N
authors.initials: N
authors.lastname: Owen
authors.forename: A
authors.initials: A
authors.lastname: Bauman
mesh_terms: D000328:Adult; D001315:Australia; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D009626:Terminology as Topic; D014481:United States