The risk of exercise addiction, characterized by an uncontrollable urge to engage in physical activity, poses significant health risks yet lacks clinical diagnostic criteria. The need for its assessment is increasing in research and applied settings. The present study evaluated the psychometric properties and reliability of the Expanded Exercise Addiction Inventory (EAI-3) within a Danish population. The present study involved 392 Danish adults who were all regular exercisers. Participants completed the EAI-3, the Exercise Dependence Scale-Revised (EDS-R), the SCOFF Questionnaire for eating disorders, the Obsessive–Compulsive Inventory-Revised (OCI-R), and the Ten-Item Personality Inventory (TIPI). Confirmatory factor analysis (CFA) and measurement invariance testing were performed to assess the factor structure and reliability of the EAI-3 across biological sex. The results indicated strong reliability and validity for the EAI-3, with good fit indices across models (CFI =.981, RMSEA =.054). The scale scores demonstrated configural, metric, and scalar invariance, indicating consistent performance across male and female exercisers. Reliability analyses yielded high internal consistency (α =.85, ω =.88), and ROC analysis established a cut-off score of 33.5 for potential exercise addiction risk, with high specificity (.856) and sensitivity (.889). Similar good results emerged from the bifactor model, but the original structure was still preferable. The present study supports the EAI-3 as a valid and reliable tool for screening the risk of exercise addiction among Danish adults, facilitating early identification and potential intervention. Further research should focus on longitudinal studies and clinical validations to enhance the understanding and management of exercise addiction.

The Exercise Addiction Inventory-3 is the latest version of the Exercise Addiction Inventory, whose use has become more frequent in several countries. The present study investigated its psychometric properties among Turkish adults. The study recruited 389 participants through online social media platforms. Reliability was tested through Cronbach’s alpha and McDonald’s omega. Validity was tested through correlations among the Exercise Addiction Inventory-3 score and scores on the Exercise Dependence Scale-Revised, Ten-Item Personality Inventory, SCOFF Questionnaire, and Obsessive-Compulsive Inventory-Revised. Structural validity was tested via confirmatory factor analysis and measurement invariance. The findings suggested that the Turkish version of the Exercise Addiction Inventory-3 is reliable. Moreover, confirmatory factor analysis indicated that the models demonstrated good to excellent fit indices. Partial measurement invariance was observed. The Exercise Addiction Inventory-3 scores were positively correlated with the Exercise Dependence Scale-Revised and Obsessive-Compulsive Inventory-Revised scores. The total scale score and the Addiction Tendency subscale score were negatively correlated with SCOFF scores but not the Health Relevance subscale scores. The Turkish Exercise Addiction Inventory-3 is a reliable and valid instrument to assess the risk of exercise addiction that differentiates at-risk groups from passionate exercisers. Implications for future studies are discussed.