Abstract
The practice of physical activity (PA) is a healthy habit that offers health benefits. In contrast, the lack thereof may be associated with an increase in diseases, even at an early age. The objective of this study was to analyze the association between unhealthy behaviors, such as tobacco consumption and problematic internet use, and the practice of PA in adolescents. Protective factors (physical activity and sport) and risk factors (leading a sedentary life, tobacco use, and problematic internet use) were evaluated. Other variables such as sex, the intensity of physical activity, and being a member of a sports federation were also evaluated. The sample consisted of a total of 1222 Spanish adolescents. Univariate descriptive analysis and multiple linear regression were used, and confirmatory factor analyses and structural models were also estimated. The results confirm a significant positive association between physical activity, intensity, and being a member of a sports federation, as well as between cigarette consumption and internet use. It is advisable to implement public policies that promote the practice of sports as a direct investment in health, preventing the consumption of tobacco and other habits that are harmful to the health of adolescents.