Psychometric Properties of a Physical Activity and Sedentary Behavior Identity Scale (Preprint)

BACKGROUND Emerging evidence suggests a positive association between relevant aspects of one’s psychological identity and physical activity engagement, but the current understanding of this relationship is primarily based on scales designed to assess identity as a person who exercises, leaving out essential aspects of physical activities (e.g., incidental and occupational physical activity) and sedentary behavior. OBJECTIVE The goal of this study is to evaluate the validity of a new physical activity and sedentary behavior identity scale (PA/SB identity scale) using two independent samples of U.S. adults. METHODS In study 1, participants answered 21 candidate items for the PA/SB identity scale and completed the International Physical Activity Questionnaire-Short Form (IPAQ-SF). Study 2 participants completed the same PA/SB identity items twice over a 1-week interval and completed the IPAQ-SF at the end. We performed factor analyses to evaluate the structure of the PA/SB identity scale, evaluated convergent validity and test-retest reliability (in study 2) of the final scale scores, and examined their discriminant validity using tests for differences in dependent correlations. RESULTS The final PA/SB identity measure was comprised of 3 scales: physical activity role identity (F1), physical activity belief (F2), and sedentary behavior role identity (F3), with high test-retest reliability. The F1 and F2 were positively correlated to each other, while both were negatively correlated with F3. Data from study 2 also demonstrate adequate discriminant validity. CONCLUSIONS This study provided initial empirical evidence from two independent studies on the reliability and validity of the physical activity and sedentary identity scales for adults.