Physical Activity Environment
MEASURES REGISTRY USER GUIDE
SECTION
2
Assessing and Defining Physical Activity Environments
Many factors influence whether or not a person engages in physical activity or meets the physical activity guideline of 150 minutes per week for adults and 60 minutes per day for youth. A vast body of research has shown that the built environment is a key determinant of physical activity, and the rationale and evidence behind this work are presented in this Section.
Why Study the Physical Activity Environment?
The Institute of Medicine,1 Centers for Disease Control and Prevention,2 National Physical Activity Plan,3 American Heart Association,4,5 and World Health Organization6 all recommend interventions to change physical activity environments as a way to increase physical activity and reduce obesity in populations. The U.S. Surgeon General also emphasized the critical role of environments in the title and theme of the 2016 report Step it Up! The Surgeon General’s Call to Action on Walking and Walkable Communities.7 It is intuitive that some places are better than others for physical activity, but intensive study, mainly in the 21st century, has defined many environmental features that hold promise for increasing physical activity.
Many groups in communities across the United States and worldwide are working to create more activity-friendly environments. The goal of most of these efforts is to make it easier, safer, and more comfortable for people to choose to be physically active in their daily lives. It has become clear that different types of environments can be designed to facilitate different purposes, or domains, of physical activity. Well-designed parks, playgrounds, school grounds, trails, recreation centers, and health clubs can support leisure-time physical activity. Neighborhoods designed so people can walk to nearby destinations, along with safe facilities for pedestrians and bicyclists, can increase walking and bicycling for transportation. Buildings sited with access to public transit and multi-use trails, on-site walking paths, and designed with attractive stairs can encourage physical activity to, around, and in buildings. These environments are designed and managed by sectors of society outside of public health and medicine, including city planning, transportation, parks and recreation, architecture, landscape architecture, education, and private enterprise. Thus, researchers, practicing professionals, and policy makers in all of these sectors may be interested in measuring physical activity-related features of environments and be potential users of the physical activity environment measures in NCCOR’s Measures Registry.
Theoretical models that guide research and practice and that are widely used in the childhood obesity field include the built environment as an important factor in influencing behavior. In particular, ecological models of behavior (Figure 2) are based on the idea that behavior is influenced by a range of factors at the individual (psychology, biology), social and cultural (norms, values, interactions), environmental (social and built), and policy (laws, regulations, practices) levels. The most effective interventions are expected to be those that operate at multiple levels.8 For example, Safe Routes to School policies in transportation agencies can provide funding to improve sidewalks and street crossings near schools (environment level), support walking school buses and better enforcement of speed limits (social level), and deliver education programs to encourage walking and bicycling to school (individual level). A variety of measures are needed to evaluate the environmental, social, and individual changes produced by such multi-level interventions.
Figure 2: Ecological Model of Active Living
Source: Sallis JF, Cervero RB, Ascher W. Hernderson KA, Kraft MK, Kerr J.
An ecological approach to creating active living communities. Annu Rev Public Health. 2006; 27: 297-322.
Physical Activity Can Be Supported in Diverse Environments
Multiple settings play an important role in overall physical activity, and many public health intervention recommendations are location-specific (e.g., school-based physical activity, home-based screen time, neighborhood walking).10-12 In youth, key physical activity settings include neighborhoods, parks and recreation areas, schools, and homes.13-18 Within each of these settings, the built environment can support or not support physical activity. Some environmental features have differential impacts on youth vs. adult physical activity, as highlighted in Section 3. In general, neighborhood community design factors that support physical activity include greater residential density, a mix of residential and commercial land uses, and access to schools, parks, and recreation facilities.19-22 Neighborhood transportation system factors that support physical activity include street connectivity, cul-de-sacs (particularly as play areas for youth), bicycle infrastructure networks, and access to transit. Neighborhood streetscape features that support physical activity include safe street crossings, sidewalks, traffic speed bumps, and features that protect pedestrians from vehicles. Figure 3 contrasts commercial shopping areas that are designed around automobiles versus those designed with pedestrians in mind.19,23
Schools that support physical activity typically have safe outdoor play spaces as well as comprehensive school physical activity programs that include ample physical education, recess, classroom activity, and before- and after-school activity.24,25 Homes that support physical activity are those in which youth have ample access to play spaces and equipment and limited access to sedentary environments.26-29 Measures exist for assessing environments in each of these settings, though some environments do not have good coverage from existing measures, as outlined in Section 5.
Figure 3: Commercial Shopping Areas Designed for Automobiles (Low-Walkable) vs. Pedestrians (High-Walkable)
Evidence on Environments and Physical Activity
The literature on social and built environments as they relate to physical activity has grown rapidly, made possible by a sustained output of new measures, as documented in the NCCOR Measures Registry. Most of the evidence about environments and physical activity is cross-sectional, and though the studies and their findings have many inconsistencies, some findings show good agreement.30 Among adults, walkability variables are supported as correlates of walking for transportation, and proximity to recreation facilities and neighborhood aesthetics are correlates of leisure-time physical activity. Total physical activity is related to recreation facilities, transportation facilities, and aesthetics. Similar associations have been found with children and adolescents, though less consistently. It is not possible to draw conclusions for older adults due to a paucity of studies. More prospective studies in adults and older adults are available now, also with inconsistent findings.31 Critiques of physical activity and built environment research note that self-selection—the idea that people who like to walk choose residential areas that are walkable, for example—limits evidence of causality. However, several studies have assessed self-selection and neighborhood preferences and concluded that associations between built environment and physical activity are sometimes attenuated but remain significant after accounting for self-selection.32,33 The large and long-term RESIDE study of people who relocated residences in Australia showed that changes in neighborhood environments were related to changes in physical activity (e.g., Hooper, 2014; Knuiman, 2014).34,35 Studies evaluating "natural experiments," such as park improvements,36 bicycle facilities,37,38 and Safe Routes to School interventions,39,40 have shown promising results that improve evidence of causality.
Recently, interest has been growing in how built environments are related to sedentary behavior, including both total sitting time and more specific measures, such as sitting at work and screen time at home. The most consistent environmental correlate of screen time among children is having a television in the bedroom.41 A few studies of neighborhood walkability and sitting have been conducted, but results have been inconsistent.42
Multiple Users Have Multiple Uses for Physical Activity Environment Measures
Researchers can use environmental measures to advance knowledge about environmental correlates (cross-sectional studies) and determinants (prospective studies) to explore equity in access to physical activity opportunities across socioeconomic classes and geographic areas, to document and evaluate environmental changes in intervention studies, and to evaluate the effect of policies designed to change built environments, such as Complete Streets, Vision Zero, and Safe Routes to School. Practitioners in many fields can use environmental measures to assess baseline conditions as part of planning processes and to evaluate their interventions. Policy makers can use environmental data to determine the need for community improvements, to target interventions and investments where they are needed most, and to assess the outcomes. Community groups can use environmental measures to provide data to support their advocacy for community enhancements. Information regarding how to select appropriate physical activity environment measures for each of these uses is presented in Section 6.