Iran Red Crescent Med J. 2017 October; 19(10):e14057. Published online 2017 October 8. doi: 10.5812/ircmj.14057. Research Article Factors Affecting Physical Activity Behavior Among Women in Kerman Based on the Theory of Planned Behavior (TPB) Seyed Vahid Ahmadi Tabatabaei, 1 Hassan Eftekhar Ardabili, 2 Ali Akbar Haghdoost, 3 Maryam Dastoorpoor, 4 Nouzar Nakhaee, 5, * and Mohsen Shams 6 1 Assistant Professor , Social Determinants of Health Research Center, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran 2 Professor, Department of Health Education and Promotion, School of Public Health, Institute of Health Research, Tehran University of Medical Sciences, Tehran, Iran 3 Professor, HIV/STI Surveillance Research Center, WHO Collaborating Center for HIV Surveillance, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran 4 Assistant Professor of Epidemiology, Department of Epidemiology and Biostatistics, Faculty of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran 5 Professor, the Neuroscience Research Center, Kerman University of Medical Sciences, Kerman, Iran 6 Associate Professor, Social Determinant of Health Research Center, Yasuj University of Medical Sciences, Yasuj, Iran * Corresponding author: Nouzar Nakhaee, Professor, the Neuroscience Research Center, Kerman University of Medical Sciences, Kerman, Iran. Tel: +98-3432114848, Fax: +98-3432114848, E-mail: nakhaeen@yahoo.com Received 2017 March 10; Revised 2017 June 08; Accepted 2017 July 29. Abstract Background: Theory of planned behavior (TPB) has not been adequately addressed in the field of physical activity among Iranian women. Objectives: This study aimed to determine factors affecting physical activity behavior among women based on the theory of planned behavior. Methods: This cross-sectional study was conducted on 398 women in Kerman, Iran. The women were selected through the multi- stage random sampling method. Data were collected using the international physical activity questionnaire (IPAQ) and a researcher- made questionnaire based on the constructs of the theory of planned behavior and analyzed using structural equation modeling (SEM). Results: The mean age (SD) of participants was 36.9 (9.9). Perceived behavioral control (β = 0. 16, P = 0. 013) and behavioral intention (β = 0.16, P = 0.005) had a significant positive direct effect on physical activity behavior. Moreover, instrumental attitude (β = 0.04, P = 0.003), subjective norms (β = 0.04, P = 0.003) and perceived behavioral control (β = 0.03, P = 0.002) had a significant positive indirect effect on physical activity behavior. Behavioral intention and perceived behavioral control constructs predicted 6% of variance of physical activity behavior. Conclusions: Given that the constructs of behavioral intention and perceived behavioral control could predict physical activity be- havior, health promotion interventions should be designed with an emphasis on these factors in order to promote physical activity in women. Keywords: Physical Activity, Behavior, Theory of Planned Behavior, Women 1. Background Physical activity reduces the risk of over 25 chronic dis- eases, including cardiovascular disease, type 2 diabetes, os- teoporosis, and breast and colon cancers (1). Physical ac- tivity can help improve women’s health and prevent many diseases in women (2). According to the recommendation of the world health organization (WHO), the heart associa- tion, and the American college of sports medicine, individ- uals aged 18 to 65 years, who do less than 150 minutes per week of moderate physical activity (30 minutes daily for 5 days per week) or less than 75 minutes of intense physical activity (25 minutes, 3 times a week) are considered to have low mobility (3). Despite the enormous benefits of physical activity, a high percentage of adults do not engage enough in physical activity (4). Based on a systematic review con- ducted in 2016 in Iran, 30% to 70% of the population of Iran had low mobility or was inactive (5). In order to design ef- fective health promotion strategies to change the behavior of physical activity and the complexity of this behavior, we need to understand better factors affecting our physical ac- tivity (2, 6). One of the social-cognitive-based theories of behavior change is the theory of planned behavior (TPB), which is used to predict and understand behavior. This theory is Copyright © 2017, Iranian Red Crescent Medical Journal. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited.