Psychosocial determinants of physical activity behavior in postgraduate students in Yogyakarta

Introduction: Graduate students face a high risk of adopting a sedentary lifestyle due to academic demands and stress. Although physical activity is crucial for health, there remains a gap in understanding the psychosocial factors that influence this behavior in specific populations. This study aimed to test an expanded Theory of Planned Behavior (TPB) model by incorporating Anticipated Affect and Habit to analyze the determinants of intention and physical activity behavior among postgraduate students in Yogyakarta. Methods: Using a quantitative approach, 249 postgraduate students (Master’s and Doctoral) were recruited via voluntary sampling. Data were analyzed using Partial Least Squares Structural Equation Modeling (PLS-SEM). The research instrument measured core TPB constructs (Attitude, Subjective Norms, Perceived Behavioral Control – PBC), additional constructs (Habit, Anticipated Affect), Intention, and actual physical activity behavior (T_MET) using the International Physical Activity Questionnaire Short Form (IPAQ-SF). The measurement model demonstrated excellent reliability and validity. The structural model showed a high predictive power for Intention, explaining 75.1% of its variance (R² = 0.751). Anticipated Affect (β = 0.353), Habit (β = 0.221), and PBC (β = 0.205) were the strongest predictors of Intention. In contrast, the model demonstrated a very weak association with actual physical activity behavior (T_MET), with R² = 0.002. Results: All hypothetical pathways to Behavior (from Intention, Habit, and PBC) were found to be statistically insignificant. These findings suggest a weak intention–behavior correspondence among graduate students. Although emotional factors and habitual tendencies strongly shape intention, they are insufficient to translate into actual physical activity. Conclusion: Contextual limitations, including unmeasured environmental factors, may contribute to this limited translation from intention to behavior. Health interventions on campuses may benefit from integrating volitional strategies (such as implementation intentions) and creating a supportive environment to help students bridge the intention–behavior gap.