Background: It is not always clear whether physical activity is causally related to health outcomes, or whether the associations are induced through confounding or other biases. Randomized controlled trials of physical activity are not feasible when outcomes of interest are rare or develop over many years. Thus, we need methods to improve causal inference in observational physical activity studies. Methods: We outline a range of approaches that can improve causal inference in observational physical activity research, and also discuss the impact of measurement error on results and methods to minimize this. Results: Key concepts and methods described include directed acyclic graphs, quantitative bias analysis, Mendelian randomization, and potential outcomes approaches which include propensity scores, g methods, and causal mediation. Conclusions: We provide a brief overview of some contemporary epidemiological methods that are beginning to be used in physical activity research. Adoption of these methods will help build a stronger body of evidence for the health benefits of physical activity.
Brigid M. Lynch, Suzanne C. Dixon-Suen, Andrea Ramirez Varela, Yi Yang, Dallas R. English, Ding Ding, Paul A. Gardiner and Terry Boyle
Juana Willumsen and Fiona Bull
Background: Physical inactivity is a leading risk factor for global mortality and a contributor to the increase in overweight and obesity. The Commission on Ending Childhood Obesity identified the need for guidance on physical activity, particularly for early childhood (<5 y), a period of rapid physical and cognitive development. Methods: The World Health Organization (WHO) has developed the first global guidelines on physical activity, sedentary, and sleep behaviors, building upon high-quality systematic reviews. The WHO guideline process is a rigorous, systematic, and transparent method for the development of recommendations, using the Grading of Recommendations Assessment, Development and Evaluation Evidence to Decision framework. It takes into consideration the strength of the evidence as well as values and preferences, benefits and harms, equity and human rights. Results: The authors summarize the first global guidelines on time spent in physical activity, sedentary behavior (including screen time and time spent restrained), and sleep patterns in infants (birth to 1 y of age), toddlers (1–2.9 y of age), and preschoolers (3–4.9 y of age). Conclusions: WHO is actively disseminating and supporting implementation of these guidelines by national adoption and adaptation, through links with early childhood development and the Global Action Plan on Physical Activity 2018–2030.
Stephanie A. Hooker, Laura B. Oswald, Kathryn J. Reid and Kelly G. Baron
Background: Little is known about how daily fluctuations in health behaviors relate to chronic disease risk. The goal of this study was to examine whether variability in physical activity, caloric intake, and sleep is related to body composition (body mass index and body fat percentage). Methods: Healthy adults (N = 103; 64% female) were monitored for 7 days to assess physical activity (SenseWear Armband), caloric intake (daily food diaries), and sleep duration and timing (Actiwatch Spectrum). Data were analyzed using correlations (between- and within-subjects correlations) and regression. Results: The results demonstrated that variabilities in physical activity, caloric intake, and sleep were unrelated. Caloric intake and sleep variability were unrelated to body composition. At greater levels of physical activity variability, any level of physical activity was protective for body composition. Conclusions: These results suggest that among healthy adults, variabilities in health behaviors may be independent of each other, and physical activity variability may be more strongly related to body composition among those who are less active.
Jennifer E. McGarry
In her 2019 Earle F. Zeigler address, Jennifer McGarry drew on the 2017 Academy of Management Report “Measuring and Achieving Scholarly Impact” to examine how the field of sport management and the North American Society for Sport Management operationalize impact. She pointed to a broader, more inclusive, and critical examination of impact. McGarry highlighted impact on practice and impact through being explicit, particularly about the ways gender and race affect what we deem to have impact. Finally, she spoke to impact through individual and collective action, such as educating students, scholarship, and policy and advocacy. She provided examples of where we could disrupt the structures that work to maintain the status quo in terms of impact—the in-groups and the out-groups, the metrics and evaluations. She also gave examples of impact that have happened, that are happening, and that can happen even more.
Margaret McGladrey, Angela Carman, Christy Nuetzman and Nicole Peritore
Background: Rural counties in the United States face daunting structural issues that reduce their populations’ physical activity levels, including geographic isolation as well as deficits in infrastructure, public transportation, health care providers, and funding. Methods: Funding from the Centers for Disease Control and Prevention provided an opportunity to assess how Extension enhanced the collective impact of systems-level physical activity promotion programming through a multisectoral coalition in Clinton County, Kentucky. Results: The Extension-led coalition accomplished the 6 essential functions of a backbone support organization by identifying obesity as a critical local issue (function 1: providing overall strategic direction), developing a multisectoral coalition (function 2: facilitating dialog between partners), compiling data on the county’s physical activity infrastructure (function 3: managing data collection and analysis), creating communication channels (function 4: handling communication), organizing community awareness events (function 5: coordinating community outreach), and securing additional grants (function 6: mobilizing funding). The average rating of Extension’s leadership across multiple dimensions by 3 coalition members in a postproject survey was “excellent” on a 5-point Likert scale. Conclusions: Extension is well positioned through their mission, broad community engagement, data collection, needs assessment, community and academic relationships, and embeddedness in local communities to serve as the backbone support organizations for rural physical activity promotion coalitions.
Mark S. Tremblay
Background: Emerging research shows that the composition of movement behaviors throughout the day (physical activities, sedentary behaviors, sleep) is related to indicators of health, suggesting previous research that isolated single movement behaviors maybe incomplete, misleading, and/or unnecessarily constrained. Methods: This brief report summarizes evidence to support a 24-hour movement behavior paradigm and efforts to date by a variety of jurisdictions to consult, develop, release, promote, and study 24-hour movement guidelines. It also introduces and summarizes the accompanying series of articles related specifically to 24-hour movement guidelines for the early years. Results: Using robust and transparent processes, Canada, Australia, New Zealand, South Africa, and the World Health Organization have developed and released 24-hour movement guidelines for the early years: an integration of physical activity, sedentary behavior, and sleep. Other countries are exploring a similar approach and related research is expanding rapidly. Articles related to guideline development in South Africa, the United Kingdom, Australia, and by the World Health Organization are a part of this special series. Conclusions: A new paradigm employing 24-hour movement guidelines for the early years that combines recommendations for movement behaviors across the whole day is gaining momentum across the globe.
Brigid M. Lynch, Andrea Ramirez Varela and Terry Boyle
Paddy C. Dempsey, Chuck E. Matthews, S. Ghazaleh Dashti, Aiden R. Doherty, Audrey Bergouignan, Eline H. van Roekel, David W. Dunstan, Nicholas J. Wareham, Thomas E. Yates, Katrien Wijndaele and Brigid M. Lynch
Background: Recent updates to physical activity guidelines highlight the importance of reducing sedentary time. However, at present, only general recommendations are possible (ie, “Sit less, move more”). There remains a need to investigate the strength, temporality, specificity, and dose–response nature of sedentary behavior associations with chronic disease, along with potential underlying mechanisms. Methods: Stemming from a recent research workshop organized by the Sedentary Behavior Council themed “Sedentary behaviour mechanisms—biological and behavioural pathways linking sitting to adverse health outcomes,” this paper (1) discusses existing challenges and scientific discussions within this advancing area of science, (2) highlights and discusses emerging areas of interest, and (3) points to potential future directions. Results: A brief knowledge update is provided, reflecting upon current and evolving thinking/discussions, and the rapid accumulation of new evidence linking sedentary behavior to chronic disease. Research “action points” are made at the end of each section—spanning from measurement systems and analytic methods, genetic epidemiology, causal mediation, and experimental studies to biological and behavioral determinants and mechanisms. Conclusion: A better understanding of whether and how sedentary behavior is causally related to chronic disease will allow for more meaningful conclusions in the future and assist in refining clinical and public health policies/recommendations.
Xiaolin Yang, Irinja Lounassalo, Anna Kankaanpää, Mirja Hirvensalo, Suvi P. Rovio, Asko Tolvanen, Stuart J.H. Biddle, Harri Helajärvi, Sanna H. Palomäki, Kasper Salin, Nina Hutri-Kähönen, Olli T. Raitakari and Tuija H. Tammelin
Background: The purpose of this study was to examine trajectories of leisure-time physical activity (LTPA) and television-viewing (TV) time and their associations in adults over 10 years. Methods: The sample comprised 2934 participants (men, 46.0%) aged 24–39 years in 2001 and they were followed up for 10 years. LTPA and TV time were assessed using self-report questionnaires in 2001, 2007, and 2011. Longitudinal LTPA and TV-time trajectories and their interactions were analyzed with mixture modeling. Results: Three LTPA (persistently highly active, 15.8%; persistently moderately active, 60.8%; and persistently low active, 23.5%) and 4 TV time (consistently low, 38.6%; consistently moderate, 48.2%; consistently high, 11.7%; and consistently very high, 1.5%) trajectory classes were identified. Persistently highly active women had a lower probability of consistently high TV time than persistently low-active women (P = .02), whereas men who were persistently highly active had a higher probability of consistently moderate TV time and a lower probability of consistently low TV time than their persistently low-active counterparts (P = .03 and P = .01, respectively). Conclusions: Maintaining high LTPA levels were accompanied by less TV over time in women, but not in men. The associations were partially explained by education, body mass index, and smoking.