- Click here for explanation of classification scheme.

The purpose of this systematic review is to assess, analyze, and evaluate the effectiveness of school-based interventions in promoting physical activity and fitness in school-attending children and adolescents aged six to 18 years.

The specific objectives are:

• To evaluate the effects of school-based interventions on promoting physical activity and fitness in children and adolescents 
• To evaluate the effects of school-based interventions on improving measures of physical health in children and adolescents
• To determine if certain combinations or components of school-based interventions are more effective than others in promoting physical activity and fitness in children and adolescents. 

• Randomized controlled trials and controlled trials
• School-based interventions that studied the impact of increasing physical activity among children and adolescents aged six to 18 years on promoting physical health and fitness
• School-based interventions that were conducted by staff in local public health units and used prospective designs with control group
• Interventions that included a baseline and a post-intervention measurements for primary and secondary outcomes for children and adolescents aged six to 18 years.

 

• Non-school based interventions
• School-based interventions that were implemented by nurses or medical clinicians
• School-based interventions that studied the effect of increasing physical activity among children and adolescents on health and fitness as part of a treatment regimen for a specific illness or comorbidity
• School-based interventions that were not focused on physical activity and fitness levels among children and adolescents aged six to 18 years. 

Recruitment

Search strategy: Articles searched to July 2007 from Medline, BIOSIS, CINAHL, EMBASE, Sport Discus, Psych INFO, Sociological Abstracts, and the Cochrane Central Register of Controlled Trials.

Design  Two independent reviewers rated each study according to a standardized assessment tool. This assessment tool was used to assess the methodological quality of the study and it was based on six criteria:  

1. Selection of bias
   
   • Sample identification: Whether sample was representative of the target population
   • Study participation rate:
     • Low risk: If participation rate is greater than 80%
     • Moderate risk: If participation rate is between 60-80%
     • High risk: If participation rate is less than 60%
2. Study design
   
   • Low risk of bias: RCT with adequate details regarding randomization process
   • Some risk of bias: RCT with inadequate details regarding randomization process
3. Control of cofounders
   
   • Low risk: If all potential cofounders were assessed and accounted in the analysis
   • Moderate risk: If some of the potential cofounders were assessed and accounted in the analysis
   • High risk: If potential cofounders were not assessed
4. Study blinding
   
   •  Low risk of bias: If participants were blinded to the research questions and measured outcomes
   • At risk of bias: If participants were aware of the research questions and measured outcomes
5. Data collection methods
6. Withdrawals and dropouts
   1. Low risk: If study withdrawal rate is 20% or less
   2. Moderate risk: If study withdrawal rate is between 20-40%
   3. High risk: If study withdrawal rate is greater than 40% 

 Each criterion was given one point based on an assessment scale. Studies were rated as "strong", "moderate" or "weak" based on the following:

• "Strong": A study with rating of four points "strong" or more and no "weak" points
• "Moderate": A study of less than four points rated "strong" and one "weak" rating point
• "Weak": A study with two or more points rated "weak".

Statistical Analysis

Data were presented as mean and SD with 95% confidence intervals. Results with P<0.05 were considered as significant.

 

Measurements

Standardized quality assessment tools were used by two independent reviewers to rate each study for relevance, methodological quality, and to conduct data extraction. Studies were summarized and described according to variables such as characteristics of participants, characteristics of interventions, follow-up and outcomes measured. Methodological quality of studies were compared including methods of identifying intervention and control groups, selection of participants to measure outcomes in, comparison between groups at baseline, the statistical analysis used and rates of attrition. Subgroup analysis by gender, age or ethnicity were assessed where this was both possible and conceptually sound.

Variables

• Rate of leisure time physical activity(per cent of sample engaged in moderate to vigorous activity (MVPA)). The rate of leisure time physical activity was most often assessed through self-report of MVPA during non-school time.
• Duration of physical activity (time spent engaged in MVPA). Duration of physical activity was measured primarily as minutes per hour or week spent engaged in MVPA either at school or outside of school, generally through self-report.
• Television viewing (time spent watching TV). Television viewing was measured by self-report or parental report as the minutes per hour or week spent watching television, outside of school.
• Mean systolic blood pressure (mm Hg): It was measured at baseline and immediately post-intervention during school time after a five- to 10-minute rest period in the sitting position.
• Mean diastolic blood pressure (mm Hg): It was measured at baseline and immediately post-intervention during school time
• Mean blood cholesterol (mg/dl). It was measured at baseline and immediately post-intervention during school time.
• Body mass index(BMI) (kg/m²): BMI was measured, by all but one study, at baseline and immediately post-intervention during school time by trained health professionals
• Maximal oxygen consumption (VO2 max) (mL/kg per minute): VO2max was measured in different ways at baseline and immediately post-intervention by trained health professionals during school time
• Pulse rate (beats per minute). This outcome was measured at baseline and immediately post-intervention by trained health professionals during school time, during seated rest.
   

 

 

13,841 articles were screened by researches. Out of these articles, 482 were considered potentially relevant. The 482 articles were reduced to 395 studies, by combining multiple publications of  same studies. Out of 395, 104 studies considered as meeting the search relevance criteria. Of the 104 relevance studies, only 26 were considered of sufficient quality to be included in this review. The 26 studies evaluated the impact of combinations of school-based interventions focused on increasing physical activity among children and adolescents aged between six to 18 years.

Participants were living in Australia, South America, Europe and North America.

 

 

14 studies reported results for BMI

• Grade school children: 10 studies (boys and girls)
• Adolescents (secondary school): Three studies (two only adolescent females)
• Unknown age: One study (boys and girls).

BMI Outcomes

Four studies reported significant positive effects. Positive effects were not a decrease in BMI, but a smaller increase in BMI among intervention group than control group (an average increase of one or less in BMI ratings for intervention groups vs. an increase of almost two for those in the control groups).

	Interventions	Duration
Lionis 1991	Mass media, printed educational materials, educational sessions, school curriculum, audio-visual materials, support group, community-based	Nine months
Manios 1999	Printed education materials, school curriculum, audio-visual materials, community-based	Three years
Burke 1998 (boys only)	Printed educational materials, educational sessions, school curriculum, counseling, school based activities, community-based. Five intervention groups received: Physical fitness; physical fitness plus school nutrition; school nutrition; school nutrition plus home nutrition or home nutrition	Nine months
Haerens 2006 (girls only)	Printed educational materials, school curriculum, computer-based learning, support group	Two years

10 studies reported no positive effect. The authors conclude that, “Generally, the 10 studies reporting a non-significant effect on BMI used similar combinations of interventions implemented by similar combinations of providers for similar lengths of time.”

The authors conclude that, overall, there is good evidence that school-based physical activity program interventions are not effective in either reducing BMI, or in limiting the extent to which BMI increases with age.

Other Outcomes

There is good evidence that school-based physical activity interventions are effective in

• Increasing duration of physical activity
• Reducing blood cholesterol
• Time spent watching television
• Increasing VO2 max.

However, the evidence does not suggest that school-based physical activity interventions are effective in increasing leisure time physical activity rates, or reducing systolic and diastolic blood pressure, body mass index, and pulse rate among children and adolescents aged between six to 18 years.

At a minimum, a combination of printed educational materials and changes to the school curriculum that promote physical activity result in positive effects for four of the nine studied outcomes.

 

• Since school-based physical activity interventions do not cause harm and are associated with some positive effects, such activities should continue and be encouraged by local public health unit staff to local schools and school boards
• School-based physical activity interventions should be focused on fostering positive attitudes toward physical activity and should be geared toward the developmental level of the participants
• Teachers and school staff should be encouraged to act as role models by demonstrating more physical activity during the course of the school day. This may require some dramatic changes within the working environment of teachers and school staff.
• Parental involvement could be an integral part of the school-based intervention
• More emphasis should be placed on promoting physical activity within school-based interventions (i.e. making physical activity a priority along with other healthy lifestyle behaviors)
• Public health staff should work in collaboration with teachers, schools and school boards to lobby local and provincial policy makers to increase resources for the promotion of physical activity within the school system.

 

Other:

none reported

The description of interventions was not detailed and thus it is unclear whether nutrition components were included in the interventions.