This experimental study was conducted in 2017 on middle-aged women referring to health centers in Ahwaz, Iran. The inclusion criteria were as follows: women aged 30 to 59, able to read and write, having no chronic diseases such as cardiovascular or respiratory diseases or those requiring the prohibition of physical activities, not having prohibition of mobility (being able to move, participation in educational programs and recommendations for physical activities), absence of pregnancy, absence of specific diseases, absence of a history of accidents leading to a mental and physical problem during the last month (traffic accident, death of a family member, etc.) and the willingness to participate in the research project. Exclusion criteria included reluctance to participate in the study at any time and not to attend the various stages of the research (pre-education and post-education assessments, and educational sessions).

In order to determine the sample size and taking into account the limited statistical population (160 people), the following sampling formula was considered.

$$n = frac {{ left ({Z _ {{1 – frac { alpha} {2}}} + Z_ {1 – beta}} right) ^ {2} left ({ delta_ {1} ^ {2} + delta_ {2} ^ {2}} right)}} {{ left ({ mu_ {1} – mu_ {2}} right) ^ {2}}}$$

We used the two-stage cluster sampling method. First, the city of Ahwaz has been divided into 4 geographic regions with roughly equal populations of middle-aged women. Two centers (intervention and control groups) were selected in each region (a total of 8 centers). Then, each center was referred and based on the inclusion criteria, a list of middle-aged women was prepared from the centre’s household files, and 20 individuals were selected from a simple random selection. (in total 160 individuals).

We used a cluster sampling method based on other studies [17,18,19,20].

### Educational intervention

The intervention program was carried out over a period of 2 months for the intervention group. It consisted of 4 face-to-face counseling sessions, each lasting 15 minutes per month, and 4 follow-up sessions (weeks 5 to 8) after the counseling sessions for the intervention group. The first consultation session included the completion of a questionnaire for each individual to determine their state of health. Then the researcher, with the help of a specialist from the training center and a physical education instructor, gave a speech on physical activity and stressed its importance, and provided a basis for preparing the change participants to do physical activities. The second session involved a group discussion among study participants and expressed their views on whether physical activity was beneficial or not, so that each participant achieved decisional balance and perceived self-efficacy. In case of a discrepancy in the decision of each participant, the researcher and the psychologist of the center explained them and advised on how to increase their willpower. Participants were also guided to outline their goals for physical activity and to specify their direction. In the third consultation session, the researcher assessed participants’ levels of reflection and readiness for change by posting educational videos. The fourth session focused on achieving the objectives of the previous three sessions. In weeks 5 to 8, the researcher examined the extent of participants’ progress in physical activity and reassessed the level of their activities as well as the stage of change. The researcher also encouraged them and tried to find out the reasons for their failure. At the end of the 8e week, the researcher completed the questionnaire on physical activity level and stages of change for the intervention and control groups. It should be noted that after the end of the intervention, the control group received leaflets on sport and health.

The data collection tools for this study were a checklist of women’s demographic information (including their employment, spousal employment, education, education, and spousal income) and the standard questionnaire on ‘physical activity. The questionnaire consisted of two parts. The first part was based on the structures of change in the physical activities of the participants. This part consisted of 7 sections: preparation for change (questions 1-5), decision-making balance [6,7,8,9,10], perceived self-efficacy [11,12,13,14,15], pre-reflection [16,17,18,19,20], thought [21,22,23,24], preperation [25,26,27,28], practice [29,30,31,32] and maintenance [33,34,35,36]. The pre-thinking stage is the stage in which people are inactive and have no intention of starting regular physical activities in the next six months. The reflective stage is when people are inactive and are about to start regular physical activities over the next six months. In the preparation stage, individuals have irregular physical activities and do them less than three times a week and 30 minutes each time. The stage of practice is when individuals engage in regular physical activity for less than six months. At the maintenance stage, people exercise regularly for more than six months. The second part of the questionnaire was the short form of the International Physical Activity Questionnaire, which determined the physical activities of the research samples by week based on the MET-min / week. The Metabolic Task Equivalent (MET) is a unit used to estimate energy consumption in physical activities. If an individual’s MET is one, it means they are inactive. If the MET is greater than one and less than three, the level of physical activity is low. If the MET is greater than or equal to three and less than six, the intensity of physical activity is moderate, and if the MET is greater than 6, the intensity of physical activity is high. To calculate the intensity of the activities, the MET value of each activity is multiplied by the time spent in a day or in a week. This questionnaire was translated by experts and its Cronbach’s alpha coefficient was 0.72% based on a pilot study [15]. The Kappa coefficient on the validity of the Stages of Change questionnaire was also obtained at 76 by Ghahremani et al. in a study to improve physical activities [16].

This study was approved by the ethics committee of Shiraz University of Medical Sciences. To describe the data, the mean, standard deviation and frequency were used. In addition, to determine the level of consistency between the research samples in the intervention and control groups, variables such as age, education level, marital status, place of residence, spouse’s education, spouse’s occupation and type of housing were used. The Chi-square test was also applied. To examine the effect of education, the independent T test and the paired T test were also used. Data analysis was performed using SPSS 19 software and the significance level was considered to be 0.05 in all tests.