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Physical Activity: Social Support Interventions in Community Settings


What the Task Force Found

About The Systematic Review

The Task Force finding is based on evidence from a systematic review of 9 studies (search period 1980 - 2000). The review was conducted on behalf of the Task Force by a team of specialists in systematic review methods, and in research, practice, and policy related to increasing physical activity.


There is no information for this section.

Summary of Results

Nine studies qualified for review.

  • In all nine studies reviewed, social support interventions in community settings were effective in getting people to be more physically active, as measured by various indicators (e.g., blocks walked or flights of stairs climbed daily, frequency of attending exercise sessions, or minutes spent in physical activity).
    • Time spent being physically active: median increase of 44.2% (Interquartile interval [IQI]: 19.9% to 45.6%; 5 study arms)
    • Frequency of physical activity: median increase of 19.6% (IQI: 14.6% to 57.6%; 6 study arms)
    • Aerobic capacity: median net increase in of 4.7% (IQI: 3.3% to 6.1%; 5 study arms)
    • One study found that those who received more frequent support were more active than those who received less frequent support, although both highly structured and less formal support were equally effective.
  • These interventions also improved participants’ fitness levels, lowered their percentage of body fat, increased their knowledge about exercise, and improved their confidence in their ability to exercise.



Summary of Economic Evidence

An economic review of this intervention did not find any relevant studies.


Given the diversity of countries, settings, and populations included in this body of evidence, these results should be applicable to diverse settings and populations, provided appropriate attention is paid to adapting the intervention to the target population.

Evidence Gaps

Each Community Preventive Services Task Force (Task Force) review identifies critical evidence gaps—areas where information is lacking. Evidence gaps can exist whether or not a recommendation is made. In cases when the Task Force finds insufficient evidence to determine whether an intervention strategy works, evidence gaps encourage researchers and program evaluators to conduct more effectiveness studies. When the Task Force recommends an intervention, evidence gaps highlight missing information that would help users determine if the intervention could meet their particular needs. For example, evidence may be needed to determine where the intervention will work, with which populations, how much it will cost to implement, whether it will provide adequate return on investment, or how users should structure or deliver the intervention to ensure effectiveness. Finally, evidence may be missing for outcomes different from those on which the Task Force recommendation is based.

Identified Evidence Gaps

  • What type of social support and what medium works for whom?
  • Do intensity and structure of the support make a difference?
  • How does effect size vary by frequency of social interaction?
  • Does the effect of these interventions vary by gender?

General Research Issues


The following outlines evidence gaps for reviews of these interventions to increase physical activity: Individually-Adapted Health Behavior Change Programs; Social Support Interventions in Community Settings; Family-Based Social Support; Enhanced School-Based Physical Education (archived); College-Based Physical Education and Health Education; Classroom-Based Health Education to Reduce TV Viewing and Video Game Playing; Community-Wide Campaigns; Mass Media Campaigns (archived); Classroom-Based Health Education Focused on Providing Information; Creation of or Enhanced Access to Places for Physical Activity Combined with Informational Outreach Activities.

Several crosscutting research issues about the effectiveness of all of the reviewed interventions remain.

  • What behavioral changes that do not involve physical activity can be shown to be associated with changes in physical activity?
    • For example, does a decrease in time spent watching television mean an increase in physical activity or will another sedentary activity be substituted?
    • Does an increase in the use of public transportation mean an increase in physical activity or will users drive to the transit stop?
  • Physical activity is difficult to measure consistently across studies and populations. Although several good measures have been developed, several issues remain to be addressed.
    • Reliable and valid measures are needed for the spectrum of physical activity. Rationale: Current measures are better for vigorous activity than for moderate or light activity.
    • Sedentary people are more likely to begin activity at a light level; this activity is often not captured by current measurement techniques.
    • Increased consensus about “best measures” for physical activity would help to increase comparability between studies and would facilitate assessment of effectiveness.
  • Note: This is not intended to preclude researchers’ latitude in choosing what aspects of physical activity to measure and to decide which measures are most appropriate for a particular study population. Perhaps a useful middle ground position would be the establishment of selected core measures that most researchers should use which could then be supplemented by additional measures. The duration of an intervention’s effect was often difficult to determine.


Each recommended and strongly recommended intervention should be applicable in most relevant target populations and settings, assuming that appropriate attention is paid to tailoring. However, possible differences in the effectiveness of each intervention for specific subgroups of the population often could not be determined. Several questions about the applicability of these interventions in settings and populations other than those studied remain.

  • Are there significant differences in the effectiveness of these interventions, based on the level or scale of an intervention?
  • What are the effects of each intervention in various sociodemographic subgroups, such as age, gender, race, or ethnicity?

Other Positive or Negative Effects

The studies included in this review did not report on other positive and negative effects of these interventions. Research on the following questions would be useful:

  • Do informational approaches to increasing physical activity help to increase health knowledge? Is it necessary to increase knowledge or improve attitudes toward physical activity to increase physical activity levels?
  • Do these approaches to increasing physical activity increase awareness of opportunities for and benefits of physical activity?
  • What are the most effective ways to maintain physical activity levels after the initial behavior change has occurred?
  • Are there other benefits from an intervention that might enhance its acceptability? For example, does increasing social support for physical activity carry over into an overall greater sense of community?
  • Are there any key harms?
  • Is anything known about whether or how approaches to physical activity could reduce potential harms (e.g., injuries or other problems associated with doing too much too fast)?

Economic Evidence

The available economic data were limited. Therefore, considerable research is warranted on the following questions:

  • What is the cost-effectiveness of each of these interventions?
  • How can effectiveness in terms of health outcomes or quality-adjusted health outcomes be better measured, estimated, or modeled?
  • How can the cost benefit of these programs be estimated?
  • How do specific characteristics of each of these approaches contribute to economic efficiency?
  • What combinations of components in multicomponent interventions are most cost-effective?


Research questions generated in this review include the following:

  • What are the physical or structural (environmental) barriers to implementing these interventions?
  • What resource (time and money) constraints prevent or hinder the implementation of these interventions?


Study Characteristics

  • In the typical intervention, volunteers were grouped to provide companionship and support to help each other reach self-selected activity goals. Study participants received phone calls from other participants and from study staff members to monitor progress and encourage them to continue their activities.
  • Some studies involved formal discussion groups to address barriers to exercise and negative perceptions about activity.
  • Studies were conducted in the United States (7 studies), Canada (1 study), and Australia (1 study).
  • Studies were offered in community settings, including community centers and churches (6 studies), a worksite (1 study), and a university (2 studies).
  • Six studies exclusively or primarily reported results for women, and three studies also included men in their study populations.
  • Study populations for most studies were middle-aged; one study included women aged 18 years or older, and one study focused on women ages 50 to 65 years.
  • Three studies restricted their populations to people who were sedentary at the beginning of the study; the rest included people at any initial level of activity.