validity and reliability of the basic psychological needs in exercise scale (bpnes)

the aim of this study was to determine the validity and reliability of the basic psychological needs in exercise scale (bpnes). the method was descriptive-survey. the statistical population consisted of male and female athletes aged over 16 years who attended structured exercise programs. the sample consisted of 256 male and female athletes (m=23.03, sd=4.04) who were selected through cluster random sampling method. the 12-item basic psychological needs in exercise scale was initially translated (by translation - back translation method) and then its face and content validity were confirmed. after a pilot study and necessary modifications, confirmatoryfactoranalysis (cfa) was used to examine construct validity. cronbach's alpha coefficient was used for internal consistency of the scale and temporal reliability of the items. intra-class correlation coefficient (icc) was examined by test-retest method with 2-4 weeks of interval for the scale and subscales. the results showed that the second model of bpnes had acceptable fit indexes (cfi=0.98, rmsea=0.07), internal consistency (alpha coefficient: 0.87 for relatedness, 0.80 for competence, 0.82 for autonomy, and 0.88 for the whole questionnaire) and temporal reliability (0.88 for relatedness, 0.83 for competence, 0.83 for autonomy, and 0.90 for the whole questionnaire). so, this scale can be used for research population in iran.