Thesis (D.A.T., Movement & Leisure Sciences) -- University of Idaho, 2017 | The capstone product of the Doctor of Athletic Training (DAT) program is a Dissertation of Clinical Practice Improvement (DoCPI), and this extensive document highlights my evolution as an athletic trainer into a scholarly practitioner. Included in my DoCPI is the Plan of Advanced Practice (PoAP) that builds the foundation by which I work toward advanced practice and identifies my current clinical practices, strengths, areas of needed improvement, and professional goals while providing a structure to evaluate my growth as a clinician. The presentation of two multi-site research studies reflects the philosophy of the DAT to engage in action research and utilize practice-based evidence to address local clinical practice challenges and enhance clinical decision-making. The exploration of the effects of Mulligan Concept® thoracic sustained natural apophyseal glides (SNAGs) for the treatment of secondary impingement syndrome provided a means of investigating the regional interdependence model by indirectly treating shoulder pain via the scapulothoracic region. Further investigation of Mulligan Concept® positional SNAGs provided a foundation for the direct treatment of non-traumatic musculoskeletal injury of the cervicothoracic region without hesitation. The insight I gained through participation in action research allowed me to apply practical solutions to specific problems within my clinical setting, and the following DoCPI provides evidence of how I integrated and applied action research within my clinical setting, demonstrating my journey from a novice athletic trainer to advanced practitioner.