Theoretical Models and Interventions to Increase Physical Activity Among Adults: A Historical Review

Meenakshi Khatta, MS, CRNP


Topics in Advanced Practice Nursing eJournal. 2008;8(1) 

In This Article


The content of the counseling message should be based on empirical data from trials of physical activity counseling interventions. Unfortunately, little research within theoretical frameworks has been conducted to guide practitioners. An exception is Project PACE (Provider-based Assessment and Counseling for Exercise),[15] a trial based on Stages of Change Theory,[16] and Social Cognitive theory.[17] Twelve primary care physicians provided 3 to 5 minutes of physical activity counseling for their patients.[15] Counseling was tailored to the patients level of activity and readiness. A health educator provided a follow-up telephone call after the initial visit. Evaluations of Project PACE by the trained physicians indicated that 75% would recommend PACE to other physicians and more than 50% reported increase in their patient's activity levels.[18]

Theories should guide research concerning factors that influence adult physical activity. Social support, self- efficacy, and beliefs about the outcome of physical activity have been closely related to increase in physical activity among adults. Exercise enjoyment, which is not a part of any behavioral theory, has also been associated with physical activity.

Learning theories emphasize that learning a new, complex pattern of behavior, like changing from a sedentary to an active lifestyle, normally requires modifying many of the small behaviors that compose an overall complex behavior.[19] A complex behavior change, such as walking 30 minutes daily, can be learned by first breaking into smaller segments. What complicates this change further is that new behavior must replace or compete with the former pattern of inactive behavior. Reinforcement describes the consequences that motivate individuals either to continue or change the behavior.[17,19]

Most behaviors, including physical activity, are learned and maintained under fairly complex schedules of reinforcement and anticipated future rewards. Although providing praise, encouragement and other extrinsic rewards may help people adopt positive lifestyle behavior, such external reinforcement may not be reliable in sustaining long-term change.[20]

The Health Belief Model (HBM) addresses:[21,22]

  • The individual's perceptions of the threat posed by a health problem;

  • The benefits of taking a preventive action; and

  • Factors influencing the decision to act.

Because health motivation is its central focus, the HBM is a good fit for addressing problem behaviors that evoke health concerns (eg, driving without wearing a seat belt and associated higher mortality if in a car accident). When applying the HBM to planning health programs, practitioners should understand how susceptible the target population feels to the health problem, whether they believe it is serious, and whether they believe action can reduce the threat at an acceptable cost. Attempting to effect changes in these factors is never easy.

In the Transtheoretical Model, more commonly known as the Stages of Change Theory or Model, behavior change has been conceptualized as a 5-stage process or continuum related to a person's readiness to change:[23]

  1. Precontemplation;

  2. Contemplation;

  3. Preparation;

  4. Action; and

  5. Maintenance.

People at different points along the continuum have different informational needs and benefit from interventions designed for their stage. The Stages of Change Theory has been applied to a variety of individual behaviors, as well as organizational change. The model is circular, not linear. This means that people do not have to systematically progress from 1 stage to the next. Instead, they may enter the change process at any stage relapse to an earlier stage and begin the process once more.

The Theory of Planned Behavior (TPB)[24] and the associated Theory of Reasoned Action (TRA) explore the relationship between behavior and beliefs, attitudes and intentions.[25] Both TPB and TRA assume behavioral intention is the most important determinant of behavior. According to these models, behavioral intention is influenced by a person's attitude toward performing a behavior, and by beliefs about whether individuals who are important to the person approve or disapprove of the behavior.

At the interpersonal level, theories of health behavior assume individuals exist within, and are influenced by, a social environment. The opinions, thoughts, behavior, advice, and support of the people surrounding an individual influence his or her feelings and behavior, and the individual has a reciprocal effect on those people. Many theories focus on interpersonal level but Social Cognitive Theory (SCT) is one of the most frequently used. SCT describes a dynamic, ongoing process in which personal factors, environmental factors, and human behavior exert influence upon each other.[17] According to SCT, 3 main factors affect the likelihood that a person will change a health behavior: (1) self-efficacy; (2) goals; and (3) outcome expectancies.

If individuals have a sense of personal agency or self-efficacy, they can change behaviors even when faced with obstacles. If they do not feel that they can exercise control over their health behavior, they are not motivated to act, or to persist through challenges. Behavior is not simply a product of the environment and the person, and the environment is not simply a product of the person and behavior.


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