Grace, Stephanie2024-03-292024-03-292024-02https://hdl.handle.net/11299/261982University of Minnesota Ph.D. dissertation. February 2024. Major: Kinesiology. Advisor: Daheia Barr-Anderson. 1 computer file (PDF); xi, 209 pages.Many emerging adults use (aged 18 to 29) social media and cite them as primary sources of health-related information, including physical activity (PA) information. Instagram is among the most popular social media sites, and fitness-related content on Instagram is commonly researched, particularly regarding negative well-being outcomes associated with its use. However, PA promotion professionals are turning to Instagram (and other sites) to create innovative strategies that reach larger, more diverse populations. Yet, there is a limited understanding of emerging adults’ behavior and experiences regarding fitness-related Instagram use, and little work that investigates these topics among samples diverse in gender and racialized/ethnicized identities. This dissertation uses mixed-methodologies to (1) gain a more comprehensive understanding of young people’s fitness-related Instagram use and how it relates to their PA participation and (2) investigate the role of relevant psychosocial and behavioral factors in the relationship between fitness-related Instagram use and PA participation among a diverse sample of emerging adults. This dissertation includes three study manuscripts in Chapters 4, 5, and 6. Participants (N=247) completed a cross-sectional survey regarding their demographic information, fitness-related Instagram use, PA participation, PA information seeking behavior, and exercise self-schema. Chapter 4 discusses descriptive characteristics of participants’ fitness-related Instagram use and explores differences by gender and racialized/ethnicized identities. Chapter 5 examines the relationship between fitness-related Instagram use and PA, including the roles of PA information seeking and exercise self-schema. Chapter 6 reports findings from focus groups with 17 emerging adults who access fitness-related Instagram content daily, specifically related to their use practices and perceptions of content and its influence on their PA behavior. Overall, this dissertation uses a mixed-method approach to yield a more comprehensive understanding of fitness-related Instagram use among a diverse sample of young people so practical suggestions can be made to strengthen PA promotion programs and be mindful of cultural factors. Further, this dissertation provides insight into how emerging adults experience fitness-related Instagram content and mitigate potential harm that can occur while accessing it.enauthenticitycredibilityexercise self-schemaphysical activityrelatabilitysocial mediaThesis or Dissertation