This was a randomized controlled trial (parallel design) in which 110 middle-aged women with physical inactivity were recruited and randomly assigned to two groups using text messaging and social media to receive an intervention aimed at to promote physical activity. Inclusion criteria were age group 40-60, basic digital literacy, smartphone ownership, internet access, low International Physical Activity Questionnaire (IPAQ) score or a metabolic equivalent score (MET)

The design of this study was approved by the Ethics Committee of Ahvaz Jundishapur University of Medical Sciences (Ref. No: IR.AJUMS.REC.1396.727) and the protocol was registered in the Iranian Trials Registry. randomized clinical trials (IRCT) (Ref. No.: IRCT20170916036223N1, 29/12/2017). All participants provided written informed consent prior to data collection. This study began in November 2018 and ended in March 2019.

### Sample size

The following formula was used for sample size calculation:

begin{aligned} & {text{n}} = frac{{left( {{text{Z}}_{{{1} – alpha /{2}}} + {text { Z}}_{{{1} – beta }} } right)^{{2}} left( {{text{S}}_{1}^{2} + {text{S }}_{2}^{2} } right)}}{{left( {{text{X}}_{{1}} {-}{text{ X}}_{{2} } } right)^{{2}} }} & begin{array}{*{20}c} {{text{Z}}_{{{1} – alpha /{2}} } = {1}/{96}} & {{text{Z}}_{{{1} – beta }} = {1}. {28}} & {{text{S}}_{{1}} = {6}. {5}} & {{text{S}}_{{2}} = {6}. {9}} end{array} & begin{array}{*{20}c} {{text{X}}_{{1}} = {153}}& {{text {X}}_{{2}} = {157}. {7}} & {n = frac{{left( {1.96 + 1.28} right)2left( {6.5 + 6.9} right)2}}{{left( {153 – 157.7} right )2}} = 43} end{array} end{aligned}

We considered 25% for attrition and the total sample size was calculated as 55.

### Recruitment

Middle-aged women who had been registered at two centers (a menopause counseling clinic and a public health center) in Ahvaz, Iran, received a phone call asking them to participate in the study. A total of 131 women were assessed against the eligibility criteria, of which 110 were eligible and gave their consent to participate.

### Randomization

A random table generated by EXCEL software was used for randomization (performed by the study statistician). Due to the nature of this study, blinding of participants and researchers was not possible, but the code dedicated to each participant was kept by the secretary of the menopause clinic, and neither the researcher nor the participants did not know the code until the start of the trial. .

### Measurements

A demographic questionnaire, a checklist and the International Physical Activity Questionnaire (IPAQ) were used for data collection. The demographic questionnaire included questions on age, age at menopause, level of education, marital status, occupation and number of children. The checklist was used to record anthropometric indices (height, weight, body mass index, waist circumference, hip circumference, waist-to-hip ratio and body fat percentage).

IPAQ contains 7 questions about physical activity in the last 7 days. It includes three domains, including physical activity related to work, leisure and home. In each domain, the number of days during which the person practiced the activity for at least 10 min and the duration of the physical activity in days and minutes are requested. Total physical activity intensity was calculated using metabolic equivalence (MET). Each MET represents the amount of energy consumed per minute for a person at rest. Each MTE is equivalent to 3.5 mm of oxygen consumed per kilogram of body weight. If the total energy expended for vigorous physical activity is 1500 METs/min/week on at least 3 days in the past 7 days, or if the total energy expended for a combination of moderate and vigorous physical activity or walking is 3,000 METs/min/week, the intensity of physical activity is considered intense. Having intense physical activity for 3 days or more, having 5 days of moderate physical activity, walking at least 30 min per day, or having intense activity with a total energy expenditure equal to 600 METs/week were considered physical activity of moderate intensity. If there is no physical activity or if the activities do not meet the above conditions, they are considered low intensity [17]. The IPAQ was developed by an international group in Geneva in 1998. This questionnaire is suitable for determining the physical activity of adults aged 15 to 69 and has been used in numerous studies in different countries. The validity and reliability of this questionnaire has been endorsed in Iran by Baghiani et al. [18].

To measure the height and weight of the participants, two digital scales (Omron, made in China) were used respectively. Participants’ weight was measured while barefoot in light clothing. Their height was measured with the Omron stadiometer while they were barefoot. Body mass index (BMI) was calculated using a formula introduced by the World Health Organization (WHO) [19].

To measure the circumference of the waist and hips, a flexible measuring tape was used [20]. The German Bauer diagnostic scale (BG64 USB) was used to measure body fat percentage. After turning on the device, it was placed on a flat surface and the women were asked to walk barefoot. Participant characteristics, such as age, gender, weight, and level of physical activity, were recorded in the device. Percentages of body fat, water, muscle and bone mass, as well as basal metabolism were measured and recorded [21]. All measurements at baseline, 4, 8, and 12 weeks after surgery were performed by a trained midwife.

### Intervention

The two groups were instructed to promote their physical activity either by SMS sent on mobile or via mobile social networks. For the social networking group, a Telegram group was created and all women (n=55) were invited to join this group. Both groups received information about the need for physical activity, the benefits of physical activity, barriers to physical activity, and how to overcome these barriers. The women in the mobile text messaging group received three times a week text messages with the same content presented to the mobile social networking group.

Women in two groups were asked to complete the IPAQ before the intervention, as well as four, eight and twelve weeks after the intervention. In addition, anthropometric indices were measured over the aforementioned periods. All the women kept a diary to record their physical activity. Participants in both groups received training on how to record their physical activity, for example, they should record physical activities that lasted more than 10 minutes.

At the end of the study, individuals in both groups received payment for their Internet use (CONSORT Checklist, Supplementary Material 1).

### Statistics

Data analysis was performed using SPSS version 23. To compare quantitative variables in the two groups, the you-test was used if the distribution was normal, and if it was not normal, the Mann-Whitney test was used, which was also used for qualitative variables. The chi-square test was used for nominal or qualitative data. Paired you-test and the Wilcoxon test were used for intra-group comparisons before and after the intervention. To compare the changes in each group over weeks 4, 8, and 12, the repeated measures test was used if the data were normal, and otherwise the Friedman test was used. The significance level was set at

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