validity and reliability of questionnaire-2 of the behavioral regulations in exercise in iran

background:   behavioral regulation in exercise questionnaire-2 (breq-2) is the most commonly used tool for measurement of exercise behaviour regulation.measuring instrument in every exercise study in order to obtain accurate research data should be cross-cultural validated. the purpose of this study is to assess the validity and reliability of the iranian version of the breq-2 in a sample of university students. methods: 418 students were recruited from guilan university medical sciences for this cross sectional study. after translation, the validity of the instrument was assessed using content and construct validity (exploratory factor analysis). the reliability of the breq-2 was assessed using cronbach's alpha for internal consistency. results: the iranian version of the breq-2 was slightly modified to improve content validity. factor analysis revealed that the adapted scale included four factors with acceptable eigenvalues (α >1.0), factor loadings (α >0.4) and total variance explained (64%). study showed that breq-2 scales had acceptable internal consistency (α > 0.7). conclusion: the study concluded that breq-2 has acceptable validity and reliability in the iranian population. using breq-2 in similar studies is suggested to save time and costing.