School-Based Interventions—Elementary School. The most common intervention site is the school because it provides easy access and the opportunity to reach many children, especially if resources are limited. Most of the school-based interventions reviewed here included both a physical activity and a nutrition component. The majority worked through physical education classes, which were altered to increase the amount of time spent being active and the intensity of the activity. Most of the interventions also modified school lunch programs to reduce energy, fat, and sodium content.

The elementary school interventions generally succeeded in increasing activity in the modified physical education classes 25 49 71 77 (Table 4). Some, but not all, also increased children's out-of-school physical activity. The Cardiovascular Health in Children (CHIC) study 36 found that self-reported total physical activity increased, but other studies 49 71 found no change in out-of-school physical activity. Donnelly et al. 25 reported a decrease in out-of-school physical activity in fifth graders, although activity increased in physical education classes. Even when a family component was added to a school-based intervention, the Child and Adolescent Trial for Cardio-vascular Health (CATCH) program 49 found no increase in out-of-school physical activity, compared to the school-only intervention.

CATCH 49 and Sports, Play, and Active Recreation for Kids (SPARK) (71) performed follow-up assessments of their subjects 53 56 to determine the long-term effects of the interventions. CATCH demonstrated maintenance of higher self-reported vigorous physical activity three years after the intervention was completed, although the difference between the intervention and control groups declined with each year of follow-up 56. In the SPARK follow-up 53, schools that used trained teachers maintained the frequency and quality of PE classes more so than did schools that employed PE Specialists who were subsequently removed after the intervention and replaced with regular classroom teachers. These results indicate that long-term effects are possible through such interventions and that training existing faculty and staff may be more feasible in schools where PE Specialists are not available or would be financially prohibitive.

These results are somewhat encouraging, but suggest that future interventions must aggressively promote out-of-school physical activity. They also suggest that future studies should use more objective measures of physical activity, in order to obtain an accurate picture of in-school and out-of-school activity. A majority of the interventions reviewed here (and, in fact, virtually all interventions to date) used self-reported measures of out-of-school physical activity; these measures are very subjective and may not give a true representation of the students' activity levels. SPARK 71 used accelerometers as the primary physical activity measure; still, neither the accelerometer nor a one-day physical activity recall detected any differences in out-of-school physical activity between the intervention and control groups.

Table 4: Elementary School-based Physical Activity Intervention Programs Study Sample Intervention Physical Activity Results Cardiovascular Health in Children (CHIC) (36) N=1,274 Grades 3-4 AHA Elementary School Site Program PA Child and Adolescent Trial for Cardiovascular Health (CATCH) (49) (52) N=5,106 Grade 3-5 SCT, Organizational Change, Lunch, PE, School Policies, PE Specialists or Trained Teacher Total EE, Rate of EE in PE, Total VPA MVPA Out-of-school, Fitness Sports, Play, and Active Recreation for Kids (SPARK) (53) (71) N=955 Grades 4-5 SCT, Self-Management, PE Specialists or Trained Teacher MVPA in PE, Fitness MVPA Out-of-school, Self-Management Nebraska School Study (25) N=200 Grades 3-5 Multi-component, Nutrition Education, Lunch, PA Classroom PA Out-of-school PA Go for Health (59) (60) (77) N=409 Grades 3-4 SCT, Organizational Change, PE, Lunch MVPA in PE, PA Knowledge, PA Self-Efficacy, Out-of-school PA Oslo Youth Study (86) N=828 Grades 5-7 Smoking, Nutrition Education, PA PA for boys, Fitness for boys,   AHA, American Heart Association; EE, Energy Expenditure; MVPA, Moderate to Vigorous Physical Activity; PA, Physical Activity; PE, Physical Education; SCT, Social Cognitive Theory; VPA, Vigorous Physical Activity;, Increase; , Decrease; , No Change

School-Based Interventions—High School. Similar to elementary school programs, interventions with older children and adolescents have produced modestly positive results 22 40 43 63 (Table 5). These programs
also involved efforts to change other health behaviors, and included nutrition education, smoking cessation,
and drug education. Homel et al. 40 observed increased physical activity and reduced smoking and alcohol consumption in the Australian School Project. Students participating in the Stanford Adolescent Heart Health Program 43 and Project Active Teens 22 reported more total moderate-to-vigorous physical activity following the interventions, although the results were not consistent between boys and girls. The Slice of Life program 63 did not affect the amount of time that the ninth grade students spent exercising, but intentions, knowledge, and the intensity of their exercise improved.

The results from these high school interventions suggest that physical activity and other health behaviors can be positively influenced, although the effects seem to be attenuated in these older ages. Three of the four high school interventions reported gender differences. In Project Active Teens 22 and the Australian School Project 40, boys showed more positive changes in physical activity. Girls improved more in the Slice of Life program 63. More sustained, comprehensive, and gender-specific interventions may lead to greater increases in physical activity in the future.

Table 5: High School-based Physical Activity Intervention Programs Study Sample Intervention Physical Acivity Results Australia School Project (40) N=3,200 Grades 9-12 Physical Heath, Substance Abuse, Emotional Health Health behavior scores for boys, Out-of-school PA Stanford Adolescent Heart Health Program (43) N=1,447 Grade 10 SCT, PA, Nutrition Education, Smoking Stress, Problem Solving Regular exerciser Project Active Teens (22) N=599 Grades 9 Conceptual PE MVPA in grades 11 and 12 for boys, Strengthening exercises in girls VPA, Flexibility exercises Slice of Life (63) N=270 Grades 9 SCT, PA, Nutrition Education, Specialist- and Peer-led Sessions Knowledge, Time spent excercising   AHA, American Heart Association; EE, Energy Expenditure; MVPA, Moderate to Vigorous Physical Activity; PA, Physical Activity; PE, Physical Education; SCT, Social Cognitive Theory; VPA, Vigorous Physical Activity;, Increase; , Decrease; , No Change

Similar to the Family Health Project, other interventions have attempted to intervene in home settings 85 by using family contracting and parent training. Although no control group was used, physical activity levels of the low-fit children increased up to a total of 110 minutes per day. Several studies 44 48 64 conducted in adults have found promising results using the primary care setting as the source for physical activity counseling. Recently, the Physician-based Assessment and Counseling for Exercise (PACE) program 48 expanded to include children and adolescents, although results of this effort are not yet available.

Taken together, these results suggest that physical activity intervention at the community level is much more difficult than intervention at the school level. The Minnesota program, which implemented components at both levels (via mass media, community risk factor screenings, food labeling at grocery stores, school physical education and health curricula) effected some positive changes in physical activity 42. Intervening at the family level or following a fitness center-based approach may not be adequate if the whole community environment does not also change and support the concepts presented to families and individuals.

Table 6: Community-based Physical Activity Intervention Programs Study Sample Intervention Physical Acivity Result Class of 1989 and Minnesota Heart Health Program Study (42) N=2,376 Grade 6 SCT, Social Influences Model, Restructure Social and Physical Environment Exercise, PA Exercise after Grade 7 Family Health Project (55) N=206 Grades 5-6 206 Families SCT, Interactive Education PA Center-Based Program for Families (7) N=102 Mean Age=10.7 94 Families PA, Nutrition Education, Fitness Center PA, Fitness, Knowledge, Self-Efficacy, Low participation (28%)   AHA, American Heart Association; EE, Energy Expenditure; MVPA, Moderate to Vigorous Physical Activity; PA, Physical Activity; PE, Physical Education; SCT, Social Cognitive Theory; VPA, Vigorous Physical Activity;, Increase; , Decrease; , No Change

Clearly, more work is needed to identify successful intervention strategies. Several other school-based and community-based programs are currently underway and the results from these recent efforts should provide additional information that can be incorporated into future programs. Although school-based programs allow easy access to children, they may require additional support from outside the school to encourage youth to be more physically active. Support should be recruited from community organizations and programs such as local parks and recreation departments, community sports programs, YMCAs, and YWCAs 18.

Communication among schools, community organizations, and individuals is critical to the success of any effort to improve physical activity and dietary behaviors on such a large scale. Table 7 provides several practical tips and suggestions that can be used to increase the physical activity of children and youth. The Guidelines for School and Community Programs to Promote Lifelong Physical Activity Among Young People 18, published by the Centers for Disease Control and Prevention, provides a more comprehensive list of recommendations.