Abstract
(1) Background: Although social cognitive theory (SCT) has been widely tested and applied in numerous interventions aimed at optimizing physical activity behavior, the complete theory has rarely been tested in its entirety. Only selected elements have been tested, and specific samples, some of them pathological, have been studied rather than the general population, for whom a lack of physical activity is a huge problem. The present study addresses these two research gaps and tests the tenability of the theoretical assumptions of SCT to explain physical activity behavior in the general population. (2) Methods: A total of 194 German adults (109 male, 85 female) with a mean age of 26.03 years (SD = 10.33) completed two validated questionnaires concerning their expressions on SCT components (t1) and their physical activity (t2). SCT was modeled using a structural equation model with latent variables. (3) Results: The results showed the very good fit of the structural model, indicating that the theoretically stated relations between the constructs in SCT seem to be corroborated, despite some paths seeming to be more important than others. (4) Conclusions: The use of SCT to explain and predict behavior can be seen as justified, even though it once again appears that some aspects (i.e., self-efficacy) are more crucial than others.