title: Validation and psychometric evaluation of physical activity belief scale among patients with type 2 diabetes mellitus: an application of health action process approach.
abstract: BACKGROUND
  Moderate increase in physical activity (PA) may be helpful in preventing or postponing the complications of type 2 diabetes mellitus (T2DM). The aim of this study was to assess the psychometric properties of a health action process approach (HAPA)-based PA inventory among T2DM patients.
  
  
  METHODS
  In 2015, this cross-sectional study was carried out on 203 participants recruited by convenience sampling in Isfahan, Iran. Content and face validity was confirmed by a panel of experts. The comments noted by 9 outpatients on the inventory were also investigated. Then,the items were administered to 203 T2DM patients. Construct validity was conducted using exploratory and structural equation modeling confirmatory factor analyses. Reliability was also assessed with Cronbach alpha and interclass correlation coefficient (ICC).
  
  
  RESULTS
  Content validity was acceptable (CVR = 0.62, CVI = 0.89). Exploratory factor analysis extracted seven factors (risk- perception, action self-efficacy, outcome expectancies, maintenance self-efficacy, action and coping planning, behavioral intention, and recovery self-efficacy) explaining 82.23% of the variation. The HAPA had an acceptable fit to the observations (χ2 = 3.21, df = 3, P = 0.38; RMSEA = 0.06; AGFI = 0.90; PGFI = 0.12). The range of Cronbach alpha and ICC for the scales was about 0.63 to 0.97 and 0.862 to 0.988, respectively.
  
  
  CONCLUSIONS
  The findings of the present study provided an initial support for the reliability and validity of the HAPA-based PA inventory among patients with T2DM.
authors.affiliation: Student Research Center, Faculty of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hosein
authors.initials: H
authors.lastname: Rohani
authors.affiliation: Department of Health Education And Promotion, Faculty of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Ahmad Ali
authors.initials: AA
authors.lastname: Eslami
authors.affiliation: Social Determinants of Health Research Center, Kurdistan University of Medical Sciences, Kurdistan, Iran.
authors.forename: Arsalan
authors.initials: A
authors.lastname: Ghaderi
authors.affiliation: Department of Biostatistics, Faculty of Health, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Tohid
authors.initials: T
authors.lastname: Jafari-Koshki
authors.affiliation: Department of Biostatistics, Kermanshah University of Medical Sciences, Kermanshah, Iran.
authors.forename: Erfan
authors.initials: E
authors.lastname: Sadeghi
authors.affiliation: Department of Epidemiology, Sabzevar University of Medical Sciences, Sabzevar, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Bidkhori
authors.affiliation: Department of Basic Sciences, Qom University of Medical Sciences, Qom, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Raei
keywords: Diabetes mellitus; Health action process approach; Health behavior; Physical activity; Psychometric properties; Validation