The purpose of this study was to assess the influence of social support, self efficacy, outcome expectations, and self regulation on social-cognitive determinants of physical activity for participants in a church-based health promotion study (Eileen, Wojcik, Winett and Williams, 2006). This study was carried out on the background of understanding of the role of physical activity in maintaining individual fitness and reducing risk for diseases. Although health experts have recommended engaging in physical exercises for at least 30 minutes not less than three days a week, it is evident that most Americans do not pass health fitness test. They cite lack of time and other inconveniences as reasons why they fail to engage in physical exercises. To understand factors that influence individual participation in physical activities, researchers have found it necessary to identify demographic factors that influence participation in physical activities. There are also psychosocial factors like self-efficacy, which is individual confidences in their ability to engage in physical exercises, social support, outcome expectations, and self regulation.