Background: Sedentarism is uniquely associated with numerous health problems (e.g., obesity). School-age youth spend a considerable portion of their time being sedentary, although relatively little attention has been given to examining youth sedentary time or behaviors during school. Purpose: This systematic review and meta-analysis examined sedentarism (time, behaviors) in children and adolescents during school hours. Methods: Two separate electronic-databases searches were conducted. The first focused on sedentary time and looked for studies that: (1) were conducted in the U.S., (2) targeted the K-12 setting during school-day hours, (3) were an intervention, (4) included objective measures, and (5) reported sedentary outcomes as a time-based metric. The second search focused on sedentary behavior and looked for studies that: (1) were conducted in the U.S., (2) targeted the K-12 setting during school-day hours, and (3) included reporting of sedentary behaviors. A pooled estimate of percent-time spent sedentary was calculated. Results: On average, youth spent 63% of their time in school sedentary. There were no studies that met the inclusion criteria for the sedentary behavior portion of the review. Discussion: The limited number of studies found that report sedentary-time, coupled with the absence of studies describing sedentary behaviors, suggests that further descriptive research is needed to understand school-based sedentarism in youth. Translation to Health Education Practice: Professional development for school staff and intervention work should encompass sedentary time and behaviors across the school day.

School administrator involvement is recognized as a key factor in the extent to which school health promotion programs and initiatives are successfully implemented. The aims of this scoping review are to: (a) Identify existing documents that contain recommendations regarding the involvement of school administrators in school-based health promotion; (b) distill and summarize the recommendations; (c) examine differences in the recommendations by targeted professional level, professional group, health promotion content focus, and by whether the recommendations are evidence-based or opinion-based; and (d) evaluate the research informing the recommendations. We drew upon the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines to conduct the review. Our team conducted a comprehensive literature search with no date or geographic restrictions from January 2018 through April 2018 using four electronic databases: Academic Search Complete, Google Scholar, Physical Education Index, and PubMed. Eligibility criteria included any online documents, in English, that contained recommendations targeting school administrators’ (e.g., principals, assistant principals, superintendents) involvement (e.g., support, endorsement, advocacy) in school health programming (e.g., physical activity, nutrition, wellness). The search yielded a total of 1225 records, which we screened by title, then by abstract, and finally by full text, resulting in 61 records that met inclusion criteria. Data (e.g., recommendations, targeted contexts, targeted administrators) from these records were extracted for a content analysis. Included records contained 80 distinct recommendations, which we summarized into three themes (Collaboration, Advocacy, and Support) using a content analysis. Separate content analyses revealed no qualitative differences in the recommendations by professional level, professional group, or content focus, or by whether the recommendations were evidence-based or opinion-based. Twenty-one of the included records were peer-reviewed research articles. Using the Mixed Methods Appraisal Tool (MMAT), we appraised qualitative research articles the highest and mixed methods research articles the lowest. This review provides a basis for future research and professional practice aiming to increase school administrators’ involvement in school-based health promotion.