Data collection

The demographic data (e.g., age, marital status, literacy, etc.) of MAIW in both groups were collected through a face-to-face interview. The participates' height was determined without shoes in a standing position by a stadiometer to the nearest 0.5 cm, whereas the shoulders were in a normal state. The body weight of MAIW with wearing light clothes and no shoes or socks was measured and recorded using a SECA 768,611 balance scale (Seca™, Seca Vogel & Halke GmbH & Co., Hamburg, Germany) with an accuracy of 0.1 kg. The BMI was calculated by dividing the weight (in Kg) by the square of measured height (in m).

All the participants completed a four-question form of PA vital sign according to the IraPEN instruction [see Additional file 2]. In this checklist, the median (slow running or brisk walking) and intense (brisk running or brisk walking) PA levels are asked within a week. This parameter is expressed in metabolic equivalent tasks (MET)-min/week. One MET is usually considered to be 3.5 mL/min/kg resting oxygen consumption. The weekly total PA is obtained from the daily sum of the average (600–1500 MET-min/week) and vigorous (> 1500 MET-min/week) PA amounts during a week. According to the IraPEN guidelines, adults with a standard PA do at least 150 min of moderate aerobic PA or do at least 75 min of vigorous aerobic PA throughout the week. A person is considered sedentary if her/his PA with moderate intensity is less than 90 min. The validity of the questionnaire was confirmed by fifteen experts.

MAIW assigned to the intervention group filled up the validated HBM 96-item questionnaire in Persian before and after the designed intervention [16]. This questionnaire is based on six constituent constructs including perceived sensitivity (PSS) and severity (PSV) (17 items), cue to action (CA, 15 items), perceived benefits (PBF) and barriers (PBR) (54 items), and SE (10 items). A four-point Likert scale was used for most items (PSS, PSV, PBR, and CA) within a score range from 1 (strongly disagree) to 4 (strongly agree). Also, a five-point Likert scale was employed for the SE sub-group, ranging from 1 “not confident at all” to 5 “very confident”. Based on the items available in PSS and PSV sub-groups, the minimum and maximum score values are 17 and 68, respectively, while the PBF and PBR have a maximum score of 216 and a minimum score of 54. According to the Likert scale ranges and the number of items in the questionnaire, the lowest and highest scores for CA and SE are 15 and 60, as well as 10 and 50, respectively [16]. The internal consistency reliability of the HBM questionnaire was assessed using Cronbach’s alpha coefficient (CAC). High reliability was recognized by estimating CACs of 0.72–0.85 for the different constructs in the questionnaire. The content validity was also determined using 10 experts in the field of community health and medicine. The questionnaire was filled out face to face in an hour. The collected data before the intervention were statistically analyzed to determine with which part of the HBM questionnaire did the intervened individuals have the most difficulty.