Psychometric Properties of the Developed Theory of Planned Behavior Questionnaire about Physical Activity of Military Personnel’s Wives in Tehran

Aim: Physical inactivity, as the leading risk factor for death, is more common among women than men. Despite the effective role of extended Theory of Planned Behavior (TPB) with planning to promote exercise behavior, there is no Iranian standard scale in this regard. This research evaluated psychometric characteristics of the expanded TPB-based questionnaire regarding to the physical activity of military staff’s spouses in Tehran. Methods: Content, face, construct validity and reliability (internal consistency and stability) of this scale was assessed. A cross-sectional survey was conducted among ۲۰۰ women, who were living in organizational houses, in Tehran, Iran in ۲۰۱۴, in order to do exploratory factor analysis (EFA).The participants were chosen with multi-stage cluster random sampling. EFA was performed applying the principal component analysis and Varimax rotation. Data were analyzed using SPSS. v۱۶. Findings: Content validity index, content validity ratio and impact score of the extended TPB scale were ۰.۸-۰.۹۷, ۰.۷۸-۰.۹۸ and ۴.۵-۴.۸, respectively. An eight-factor structure was extracted as a result of the EFA and accounted for ۷۶.۳۳% of the variance. The calculated KMO was ۰.۷۲ and the Bartlett’s test of sphericity was significant (P<۰.۰۰۱). Eight constructs consisted of behavior, affective attitude, subjective norms, perceived behavioral control, coping planning, instrumental attitude, intention and action planning. Cronbach’s alpha value (۰.۸۳-۰.۹۷) and the intraclass correlation coefficient (۰.۶۳-۰.۹۱) demonstrated satisfying reliability for the subscales. Conclusion: Validity and reliability of the first developed TPB-directed scale with planning about women's exercise perceptions and behavior in Iran was appraised and approved in this study. This instrument can be utilized by other health researchers.

Keywords:

Exercise , Planning , Physical Activity , Psychometrics , Theory of planned behavior