Study design and setting
This research was a three-group intervention study, including a control group and two case groups. The number of samples was used to calculate the sample size in the Pocock analytical studies. In the present study, according to the information available in similar studies (13), taking into account the first type error of 5% and the second type of error of 0.5% for each of the 3 studied groups, the sample size was estimated to be 26.4 subjects and according to the probability of data loss, 20%, that is, 9 subjects were added to each group, and finally the study started with 96 subjects. According to the research conducted, there are 13 universities and higher education institutions in Ahvaz city, among them, based on random cluster sampling, three universities and higher education institutions were selected include Shahid Chamran University of Ahvaz, Payam Noor University of Ahvaz and ACECR- Khuzestan higher education institutions. Then, based on a simple random sampling among these three universities and institutions was selected, Shahid Chamran University as the case group receiving loss framing messages, higher education institute of ACECR-Khuzestan as the case group receiving gain framing messages, and Payam Noor University as the control group. 35 female employees were selected based on available sampling and inclusion criteria, including consent to the research, not having a medical prohibition to do physical activity, having a mobile phone and being able to use it, access to the Internet, being able to use a computer, and not being pregnant.
Data Collection Tools
The data collection tool was 2 questionnaires, including a researcher-made questionnaire based on the message framing model and the International Physical Activity Questionnaire (IPAQ), which estimated women's physical activity in the last week in terms of MET-minutes/week. This questionnaire contains 27 items and its interpretation and scoring were done based on the IPAQ scoring protocol (14). Before conducting the study, sufficient information was given to the participants and written consent was obtained from them to participate in the study. Educational messages designed in two gain and loss frameworks regarding physical activity were sent to case groups in using mobile phone (Whatsapp) for 4 weeks and one day in between. In this study, one case group was sent messages about the benefits and advantages of doing physical activity or gain messages, and another case group was sent messages about the consequences of not doing physical activity or loss messages. In gain messages, sentences such as "strength of bones and prevention of osteoporosis, especially in women, is the result of regular physical activity", in loss messages, sentences such as " inactivity causes loss of bone minerals, decrease bone mass and their weakening" was written. Between the end of the educational intervention and up to two months after that, an educational message was sent to the two case groups as a reminder every week. In order to determine the validity of the educational messages, the first version of the messages designed and reviewed by 10 experts in this field was. Data collection was done using questionnaires from all three studied groups before, immediately and 2 months after the intervention, by interview and self-report method. A specific code was given to each questionnaire, which was mentioned above. Code A was related to before the intervention, code B was related to immediately after the intervention and code C was related to 2 months after the intervention. Also, for the gain message group, the letter G, which abbreviation for GAIN, the loss message group, the letter L, which abbreviation for LOSS, and the control group, the letter C, which abbreviation for CONTROL, were given. For example, the questionnaire of the pre-test of the gain message group was coded as A-G-1. Immediately and 2 months after the end of the education, the questionnaires were completed again by all three groups.
Data analysis
Data were analyzed using SPSS software version 26. Descriptive statistics such as mean ± Standard Deviation (SD), frequency and percentage for (qualitative variables) were used to describe the quantitative and qualitative variables. one-way analysis of variance, Pearson's correlation coefficient, Repeated Measure, Paired t-Test was used to compare quantitative variables in each group. An Independent t-test was applied to compare the mean between the two groups, and a Chi-square test was used to compare the frequency of variables between the two groups. All tests were performed at a level of confidence of 95%. and the data were analyzed by SPSS version 26 software at a significance level of 0.05 with s.