Physical activity in adolescents: an expanded theory of planned behavior approach with interaction effects

Abstract

Obesity in adolescents in the United States has increased at an alarming rate over the past decade, with concerns related to the issue centered around a lifetime of greater prevalence of poor health outcomes for these individuals. Staying active and participating in daily physical activity is one of the key ways adolescents can prevent the onset of obesity early in life and increase physical and mental well-being, despite weight status. As physical activity plays a critical role in the prevention of poor physical and mental health outcomes in adolescents, it is important to understand what factors contribute to a teen’s decision to participate in physical activity. One way researchers have historically tried to understand complex decisions is through the use of psychological models. This study uses the Theory of Planned Behavior model, a model commonly used to examine decisions in the health field, to define and explore important factors contributing to physical activity in adolescents or a lack thereof. Additionally, this study expanded the Theory of Planned Behavior model to explore additional relationships among variables in the model and those impacts on physical activity in adolescents. This study uses data collected by the National Cancer Institute for The Family Life, Activity, Sun, Health, and Eating (FLASHE) study. The data from 1379 individuals was retained for the study. Participants completed up to three surveys pertaining to demographic information, information about diet, and information about physical activity. Results indicated that the original Theory of Planned Behavior Model did not fit the data well. Factors like attitude toward physical activity and perceived behavioral control over one’s ability to engage in physical activity were significant; however, the overall model did not accurately explain variations in physical activity. This may be attributed to the unique developmental and environmental circumstances of adolescents compared to the adult population for whom the model was postulated. Results also indicated a significant improvement in the model’s ability to explain adolescent physical activity when factors were allowed to covary. Further analysis showed a significant interaction effect between perceived behavioral control and subjective norms on behavioral intent. Results are contextualized and discussed in relation to contributions to research of factors involved adolescent physical activity. Study limitations and future research directions are also discussed.