Background: For people with end-stage kidney disease on hemodialysis, exercise during the dialysis treatment ( intradialytic exercise ) may promote exercise adherence and enhance aspects of the dialysis treatment. However, intradialytic exercise programs are complex and how to adapt program components to local context so that the program is more likely to attain its intended health outcomes have not been well described. To increase the uptake of exercise in clinical practice, more evidence is needed on how contextual factors influence the program’s impact. Methods: Using the realist approach, we aim to understand how the processes and structures of intradialytic exercise programs work to influence patient participation according to different contextual factors. The focus of a realist review is explanatory and aims to develop and test theory on how contextual factors trigger specific processes or behaviors ( or “mechanisms” ) to produce outcomes. Using the realist context-mechanism-outcome configuration of theory development, we will use a range of sources to develop initial candidate theories: a scoping review of published papers and the gray literature, and discussion with stakeholders. To provide a theoretical basis for how contextual factors could work to influence patient participation in intradialytic exercise ( IDE ), several of our preliminary theories will be based on dominant theories of exercise adherence and behavior change. To support or refute these initial theories, we will synthesize data from a systematic literature review and semi-structured interviews with intradialytic exercise program stakeholders, sampled from a range of programs worldwide. Discussion: The complexity of intradialytic exercise programs poses challenges to their implementation. Using the “context, mechanism, outcome” approach, the knowledge gained from this study will be used to develop general recommendations for renal care providers and administration on how to adapt components of an intradialytic exercise programs according to different contextual factors in order to promote patient participation. Systematic review registration: PROSPERO CRD4201603333
