Increasing Physical Activity by use of Social-Ecological Models
I
Introduction:
Regular physical activity (PA) is an essential and vital element of a healthy lifestyle, however, less than 24% of adults meet the physical activity guidelines set in 2008. Many Americans are spending larger portions of their time being sedentary, increasing the risk of chronic health diseases. Regular physical activity (at least 150 minutes a week) can reduce the risk associated with several chronic diseases, including cardiovascular disease (e.g. heart disease and stroke), hypertension, type 2 diabetes, certain cancers, dementia, anxiety, and depression. A study by the Centers for Disease Control and Prevention (CDC) found that 8.3% of deaths of non-disabled adults ages ≥25 were attributed to physical inactivity. The cost associated with physical inactivity exceeds $117 billion annually, accounting for more than 11% of US healthcare expenditures.7
Physical inactivity is a major societal health problem with compelling evidence supporting theoretical intervention approaches. To continue advancement in successful public health promotions that address PA, researchers, health practitioners and policymakers will need to understand and employ social behavior theories. To this point, such theories have been applied with varying degrees of success in informing and guiding public health campaigns centered around PA. This work has provided essential indicators in increasing motivational conditions, both within individuals and in the social environments under which they operate, facilitating long-term engagement in PA. However, if we are to translate this evidence for future PA programming, there remains a need to identify overlap and synergies across different theoretical frameworks and address the complexity and the multiple influences placed upon human behavior when determining PA interventions.
Of the many social behavior theories that have been used as a theoretical approach to PA, some models have been applied more frequently than others. The four most prominent models utilized within a PA context are the Social Cognitive Theory (SCT), the Theory of Planned Behavior (TPB), the Self-Determination Theory (SDT), and the Transtheoretical Model (TTM). The conclusion that PA activity is complex and multifaceted becoming more apparent in recent literature, displaying numerous layers of influence. In an effort to address these dimensions, researchers have recently embraced social-ecological models (SEM), which focus not only on the individual but seek to include social, policy, and environmental influences.
Statement of public health challenge:
There is overwhelming evidence that regular physical activity has extensive health benefits ranging from reduced risk of chronic health disease to enhanced mental health and quality of life. In contrast, lack of physical activity is associated with an increased risk of numerous causes of mortality, chronic morbidity, and disability.9 Health benefits related to exercise are well documented, and those benefits are increased with adherence to an established exercise program, prescribing regular duration and frequency.
Another indication that physical inactivity is a national public health crisis is directly related to the financial toll it takes on the US healthcare system. The direct cost associated with a lack of physical activity is approximated to be over 117 billion dollars annually. Moreover, some research suggests that inactivity and excess weight are more expensive risks than smoking or alcohol abuse.10
The prevalence of adult physical inactivity is widespread throughout the United States. Updated maps in 2020 revealed that all states and territories had more than 15 percent of adults who were physically inactive. This estimate ranged from 17.3 to 47.7 percent of the state’s population.
The South had the highest prevalence of physical inactivity (28.0%), including seven states (Tennessee, Oklahoma, Louisiana, Alabama, Kentucky, Arkansas, and Mississippi) and 2 US territories (Puerto Rico and Guam), reporting 30% or more of all adults who were physically inactive. The South was followed by the Northeast (25.6%) and Midwest (25.0%). The West demonstrated the lowest rates of physical inactivity (20.5%), with four states (Colorado, Washington, Utah, and Oregon) and the District of Columbia having 15% to 20% of adults who self-reported physical inactivity.
Since the release of the 2008 Physical Activity Guidelines (PAG), the age-adjusted percentage of adults meeting the combined aerobic and muscle strengthening goals has improved from 18.2% (2008) to 24.3 (2017).5 Despite demonstrating improvement over this 9-year period, the PAG objectives for Healthy People 2020 reflect that 80% of adults do not meet the guidelines. Similarly, more than 80% of adolescents do not do enough physical activity to meet the youth guidelines.2 Overall, only one in four urban residents(25.3%) and one in five (19.6%) rural residents (19.6%) met the combined guidelines.
A particularly concerning metric revealed in the PAG is that more than 88% of ≥ 65-year-olds do not meet the guidelines. This older population also exhibits a correlation between chronic diseases and lower levels of physical activity. Of adults age 50 or older, 80% do not meet the guidelines. In 2014, 2 in 3 adults 50 years or older had at least one chronic disease. Independently, inactivity is 30% higher in those with at least one chronic disease, including cancer, cardiovascular disease, diabetes, stroke, and obesity. The annual cost of non-institutionalized health care for adults ≥50 years is over $860 billion. Considering that 4 out of 5 of the most costly chronic conditions can be prevented or managed with physical activity, PA interventions which include exercise adherence goals become a priority for public health.
Racial and ethnic minorities are less likely to meet federal guidelines for physical activity. Figure 4 shows the percentage of adults who report doing no physical activity or exercise (such as running, calisthenics, golf, gardening, or walking) other than their regular job within a 30-day lookback.4 As of 2018, the prevalence of a sedentary lifestyle was highest among African American adults (32.2%) followed closely by Hawaiian Pacific Islanders (32.1%) and Hispanics (31.4%). Complex social, environmental, and behavioral determinants of physical activity affect these populations at disproportionate levels. (Figure 4)
Understanding the personal, social, economic, and environmental factors that play a role in individual participation in physical activity is an important tool for both successful interventions and health outcomes. Factors that are positively associated with adult physical activity include postsecondary education, higher income, enjoyment of exercise, the expectation of benefits, belief in the ability to exercise (self-efficacy), history of exercise, social support, access to and satisfaction with facilities, enjoyable scenery, and safe neighborhoods. Also important to consider when developing public health interventions are factors that are negatively associated with adult physical activity, including advancing age, low income, lack of time, low motivation, rural residency, perception of effort, being overweight or obese, being disabled and environmental barriers.11 With these factors in mind, interventions in public health have focused on four common themes:
Theme 1: Encouragement to be physically active for at least 150 minutes per week. Key to the US Department of Health and Human Services published Physical Activity and Health: A Report of the Surgeon General in 1996 supports the fact that activity is better than inactivity. From a behavior perspective this report capitalizes on good health being the main motivator to being physically active and promotes the benefits of physical activity.11 This premise that behavior change will occur when motivation aligns with ability and triggers, is supported by the Health Belief Model (HBM).6
Theme 2: Measuring Physical Activity as a Vital Sign. Introduced by Healthy People 2020, measuring activity rates by survey has been a popular public health intervention since 2008. Interventions with the goal of increasing exercise frequency have been proposed as a national process implemented by primary caregivers. During each visit with a primary care provider, the patient reports the number of minutes per week that they’ve participated in physical activity. The message conveyed is that exercise is an important part of health, similar to other vital signs of health (e.g. blood pressure). When the patient is not meeting exercise goals, a conversation can be started about the importance of physical activity in health. Ultimately, patients must be responsible for their own health and direct their level of physical activity. This intervention aligns with theories of self-regulation, a process by which people manage their own goal-directed behavior.6
Theme 3: Creating Healthy Environments by Making it Easier to be Physically Active Where We Live, Learn, Work, Play and Pray. An identified barrier to physical activity is environmental barriers which challenge in providing safe places and facilities in which to play and exercise. These interventions focus on community-wide campaigns in forming a multidisciplinary team and using community resources to promote physical activity. Some campaigns have focused on changing infrastructure to promote health and wellness, but other promotions have been as simple as creating a walk-to-school program. This intervention strategy is a central concept of social cognitive theory (SCT) and relies on cognitive processing of the environment as part of behavioral change.6
Theme 4: Monitor Disease Incidence of Patients Who are Physically Active vs. Those Who are not Physically Active. Using Healthy People 2020 physical activity objectives to promote goals for the future and increasing activity by offering conservative and obtainable goals has provided the baseline for many public health interventions over the past decade. Monitoring the relationship between health care costs and disease incidence, then comparing physically active individuals to not physically active individuals, will help develop more effective public health interventions in the future and educate the medical industry on how to better treat and prevent disease.2
This paper aims to review the theoretical perspectives commonly used as frameworks for interventions in PA, comparing the strengths and weaknesses of these theories. The conclusion of this comparison will recognize the importance of the social-ecological model (SEM.) The complexity of PA behavior is beyond explanation based on any one behavioral theory. The SEM framework encompasses a broader perspective, accounting for the dynamic interactions between people and their environment, and helps us understand the relationships between a multitude of factors.
Theoretical Approaches
Informed theoretical approaches in successful PA interventions are well-established and numerous. Two major approaches have dominated the literature one founded on social cognitive principles and the other on staged-based models.12 The limitation of using theoretical models to explain PA behavior is challenged by these models' linear approach. What is becoming more apparent in recent literature is acknowledging that changing health behavior is complex and multifaceted and that individual theories do not allow for multiple layers of influences. However, these theories can enhance our understanding of the key determinants of PA behavior and provide a framework to inform interventions.
A widely used theoretical model that many researchers have favored is the Social Cognitive Theory (SCT). Reciprocal determinism is central to SCT, providing a conceptual framework that describes the dynamic interrelationships between self-regulation and goal-directed behavior. Reciprocal determinism seeks to provide a broader context for understanding the relationship between the individual, the environment and behavior. Unique to SCT is the principle of self-efficacy, which refers to an individual’s confidence in their ability to be successful in a specific action.6 A multitude of PA-related research has utilized the construct of self-efficacy as a pre-cursor, outcome, or process variable when trying to understand PA behavior. The self-efficacy theory's predictive power and ease of operation have made it one of the most consistent predictors of health-related behavior.
Identifying the decision-making process has also been a priority in increasing PA behavior. The Theory of Planned Behavior (TPB) model has been used extensively in understanding the influencing factors of adoption, motivation, and adherence to PA. Closely related to the Theory of Reasoned Action (TRA), TPB proposes that behavior is a product of attitudes, subjective norms, and perceived behavioral control. With the construct of perceived behavior control being central to TPB, it is closely related to self-efficacy in describing one’s ability to engage in particular behaviors.6 Current research demonstrates that both TRA and TPB have performed well in explaining intentions in PA, with meta-analytic reviews consistently favoring TPB as superior to TRA in the prediction of PA behavior.12
The study of cognitions that are related to motivation has been central to understanding and promoting long-term behavior change in PA. One theory that has been used extensively, focusing on cognitions and motivation, is the self-determination theory (SDT). While initiating behavior change can result from many approaches, exercise adherence is integral for successful behavioral intervention. With approximately 50% of individuals dropping out of a PA program within the first six months,12 SDT focuses on the processes through which a person acquires the motivation to start and maintain PA behavior over time. The SDT theory proposes that individuals have three basic psychological needs; autonomy, competence and relatedness. Autonomy is the perception that one is the source or origin of one’s behavior. Competence refers to feeling effective in both interactions in the social environment and experiencing opportunities of fulfillment, while relatedness refers to belonging to individuals or communities. SDT posits that when these three basic psychological needs are satisfied, the individual’s PA will be supported, optimal motivation will be achieved and behavioral outcomes will be demonstrated.12 SDT has evolved into a theory of supporting mini-theories that all support the concept of basic psychological needs. These include the cognitive evaluation theory (CET), the organismic integration theory (OIT), and the basic needs theory, providing a vast amount of PA research under the SDT umbrella.
The second model commonly used in PA study is a stage-based approach, introduced in an attempt by researchers to overcome the limitations of social cognitive models. The most popular model in application to a PA context has been the transtheoretical model (TTM). This model seeks to integrate processes and principles across major theories; hence the name trans-theoretical.6TTM has been described as a cyclic process where individuals pass through a series of specific stages.
Each of these stages is characterized by a particular pattern of psychosocial and behavioral changes. Individuals are classified as to their readiness for change by one of the five stages: pre-contemplation, contemplation, preparation, action, and maintenance.6(Figure 5)
The cyclic process (exit and re-enter) acknowledges that several attempts at change are likely before maintenance is reached. This process of progression may strengthen behavior change as individuals learn from past regressions. The advantages of stage-based interventions in PA include the delivery of messaging being in alignment with the particular stage that an individual currently is in. It has been demonstrated that people are more likely to progress toward the action and maintenance stages when PA is addressed in a staged approach. The framework of staging also indicates how best to encourage individuals based on their behavior and progress through different stages. Conversely, critics note that there are numerous reasons that stage-based interventions may lack effectiveness. One criticism is that practitioners who are reliant on stage-based models that focus on just the individual might underestimate the complexity of other influences on the individual. Much evidence supports the impact of social factors such as age, gender, and socioeconomics, which can also direct and shape PA behavior. The TTM model fails to consider these factors.
In consideration of these gaps demonstrated in SCT and stage-based models, ecological models for PA promotion have become more influential over the past two decades. Ecological models show that individuals, interpersonal, organizational, societal, and community factors are important considerations when planning health promotion interventions. The use of this model in health promotion is considered relatively recent, although it’s an application in understanding behavior change is not new. The ecological model demonstrates an increasing acceptance of the complexities involved in behavioral change and renders the current dominance of cognitive models (projecting a linear phase stage approach to understanding PA behavior change) as incongruous. From the perspective of PA behavioral changes, numerous determinants exist whose actions impact other determinants. These determinants are often nested within numerous layers of influence. The ecological model seeks to fully comprehend and acknowledge that there must be an acceptance of the mediating role of all determinants.
The increasing acceptance of the complexities involved in PA behavior demonstrates that relying solely on one model becomes unacceptable to inform researchers fully. Currently, in the PA domain, no unified research model integrates ecological and social behavioral theories seamlessly. However, SEM studies based on multilevel interventions hold great potential for integrating individual behavior theories with social, physical, and environmental factors.
Existing research on Social-Ecological models and PA:
Increasing attention to SEM platforms in community PA interventions is being driven by acknowledging that individuals with unique motivations engage in activities that take place in particular settings and contexts. The SEM approach to public health interventions provides a framework for the dynamic interrelations that occur between an individual and their environment, the context within which they exist and the complexity of the human situation surrounding PA.
The SEM model seeks to include seven societal levels which exhibit multiple factors that affect behavior. These include individual and individual’s characteristics (intrapersonal), social relationships (interpersonal), organizational influences and factors (organizational), community characteristics (community), public policy, the physical environment, and culture. These societal levels influence behavior and act as an embedded system where each level affects other levels. There are several advancing frameworks that expand on these initial societal levels and include more directed environmental factors.
In expanding these domains and applying them to PA, Sallis et al. (2006), proposed an Ecological Model of Active Living.14This model is influenced by four domains expanding on the original SEM model to encompass: (a) intrapersonal domain including demographic, biological, and psychological effects; (b) a perceived environmental domain, including accessibility, convenience, attractiveness, and comfort; (c) behavior setting domain, including access to and characteristics of the neighborhood; and finally (d) policy environment domain with policies on physical education, facility access, transportation land use and park management.14In using this model as directed for community interventions, conjoined with social behavioral models targeted toward individual behavior changes, this SEM platform illustrates how the overlap between environment and individual influences can be mutually addressed.
A successful example of the use of SEM is found in a study by Cochrane et al. (2008), which sought to shift research focus away from the individual and to consider the whole environment.15 In an attempt to test whether an SEM approach could increase the population proportion that was physically active, two socio-economic struggling inner-cities in the UK displaying similar socio-demographical and health profiles were selected. Implementation was carried out over 21 months in five phases: preparation and piloting, initial survey estimates, community awareness campaign, PA intervention and evaluation. An intervention group and a control group were used in the collection of data for this study. Denouncing that most health promotion and public health policies focus on influencing individual behavior directly, this study focused on providing appropriate community opportunities and support. Using the SEM premise that environments influence behavior, an emphasis was placed on treating the local area and not the individual. Based upon the theory that changes in the environment in a deprived urban community should be central to promotie PA, the intervention also stressed the recognition of unhealthy behaviors and embraced the espousal of new health behavior habits.
Using the transtheoretical model (TTM) teamed with an environmental support plan, a community awareness campaign, and a physical activities program were introduced to participants in the intervention group. Advertising and peer influences were designed to move pre-contemplation candidates into contemplation by employing events, screenings, taster sessions, and peer support. These components of the interventions stimulated stage progression resulting in more candidates moving through preparatory and active stages. Maintenance levels were encouraged by setting achievement targets, involvement in competitions, and supporting individual encouragement. This SEM platform demonstrated the inclusion of TTM as a social behavioral change framework, supporting individual PA behavior outcomes. Addressing environmental factors by providing access to healthy and affordable food as well as providing better transportation opportunities to recreation and fitness areas was pivotal in offering environmental links to health behavior changes. Results revealed that relative to the control, the intervention sample demonstrated trends towards being more physically active, a greater readiness to take up PA, better perceived general health, and improved overall health results when compared with the prior year. Furthermore, 30.6%(intervention) vs. 18.3% (control) reported an increase in PA compared to one year previous.15 This study demonstrated the integration of environmental mitigation with the application of behavioral theories, displaying overall successful behavior changes in the uptake of PA, thereby reinforcing an SEM role in creating broader public health campaigns.
Conclusion
Based on the results, traditional theory-based interventions have been largely unsuccessful in promoting the uptake of PA despite the magnitude of national media campaigns, educational solid messaging, and community health promotion efforts. Public health campaigns have traditionally used social behavior models that tend to encourage or support an individual. However, the social environment that also affects PA has demonstrated in connections and relationships within a community or an organization as well as the physical environment afforded the individual. An SEM framework can be useful in addressing a broader range of PA issues providing a more inclusive understanding of the social conditions influencing PA. We can see the utility of the SEM platform in providing a framework that delivers effective environmental solutions while at the same time retaining a social behavior model perspective.
A fundamental challenge in expanding the role of SEM in health promotions is that these platforms can be complex, thus expensive. Interventions involving multiple levels require financial investments and more time and resources in administrating the programs. Care must be taken when planning SEM-based health promotions in consideration for individual’s age, cultural differences, gender, and social determinants on health, all of which require extensive attention during the development of campaigns. Nevertheless, given the significance of this public health crisis, interventions based on an SEM platform offer optimistic results in addressing PA, thereby decreasing the exorbitant toll this problem brings to public health.
In summary, my suggestions for promoting PA and achieving long-term PA adherence include incorporating a more comprehensive and ecological approach when planning and designing community interventions. Besides focusing on PA as a sole objective in these health promotion endeavors, future attention to the urban planning of the macro environment and creating transdisciplinary efforts that reduce environmental barriers to PA is both warranted and compliant within the scope of an SEM platform. Future collaboration should involve utilizing websites and other electronic devices and facilitating cross-disciplinary approaches in establishing SEM-based platforms. These efforts can only broaden and strengthen the public health perspective and potentially benefit community health by improving the uptake of physical activity.
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