Umbrella and Systematic Review Methodology to Support the 2018 Physical Activity Guidelines Advisory Committee

Introduction: In 2016, the 2018 Physical Activity Guidelines Advisory Committee, a group of experts in exercise science and health, began an extensive review of the literature to inform the second edition of the Physical Activity Guidelines for Americans. Methods: The purpose of this paper is to describe the evidence-based methodology used to review, evaluate, and synthesize published, peer-reviewed physical activity research. The protocol-driven methodology was designed to maximize transparency, minimize bias, and ensure relevant, timely, and high-quality systematic reviews. Training protocols, quality control procedures, search strategies, assessment instruments, abstraction guides and forms, and reporting templates were developed. Results: A systematic approach was used to select the evidence for the 2018 Physical Activity Guidelines Advisory Committee Scientific Report that included umbrella reviews and systematic reviews. Within 16 months, 38 searches were conducted; and 20,838 titles, 4913 abstracts, and 2139 full texts were triaged. Of those, 1130 articles were abstracted to answer 38 research questions. Conclusions: To inform population-based physical activity guidelines, this systematic process facilitated a vast review of the literature on physical activity and health in a short period of time. This flexible, yet rigorous and transparent process included a clear and detailed methodology with a focus on training and quality control.