Summary of Systematic Reviews

What is a "systematic review"?

A systematic review is a search for as many possible research studies that are available to address a research questions (e.g. What interventions are effective in increasing physical activity in children?).

Systematic reviews usually employ strict "inclusion criteria" to ensure that the research identified is indeed relevant for the question they are trying to answer, and that it is of adequate quality. Poor quality studies are often downgraded in importance or excluded from the review altogether. After close scrutiny of all available research, a systematic review includes a detailed synthesis of results, which are used to make conclusions and recommendations.

The findings from four recent systematic reviews of children and youth physical activity interventions are summarized below:

• Review 1 Evidence-based strategies to promote physical activity among children, adolescents, and young adults: review and update.
• Review 2 Interventions to Increase Physical Activity in Children and Youth
• Review 3 Interventions to Reduce Physical Inactivity in Children and Youth
• Review 4 Environmental Interventions to Improve Nutrition and Increase Physical Activity in Children and Youth.

Evidence-based strategies to promote physical activity among children, adolescents, and young adults: review and update.

Timpero, A., Salmon, J. & Ball, K. (2004).
Journal of Science and Medicine in Sport, 7 (1), 20-29.

Methods:

• Twenty-eight studies were identified between the years of 1999 to 2003 using a computer database search (MEDLINE, PUBMED, SPORTDISCUS).

Summary of Findings:

• Six of twelve studies reported a significant effect on child or youth physical activity in the school setting. Studies that incorporated whole-of-school approaches, with curricular, policy and environmental strategies, appear to be the most effective.
• Five of ten studies reported increased physical activity in children outside of the school setting. Interventions including contact with families were generally found to be the most effective.
• One study provided some evidence for the effectiveness of physical activity interventions based in primary care.
• Good evidence for effective interventions was identified in several studies for children both in and out of the school setting.
• The authors identified a general lack of rigorous intervention studies targeting young adults and subsequently no evidence of effective interventions for promoting sustained increases in physical activity in this population.

Key Messages for Policy and Program Development:

• ‘Whole of school’ approaches (i.e. incorporating curricular, policy and environmental strategies) were more effective than curriculum-based education alone
• There is a lack of evidence for effective interventions to promote sustained increased in physical activity among young adults

Interventions to Increase Physical Activity in Children and Youth

Thomas, H. (2004).
Effectiveness of Physical Activity Enhancement and Obesity Prevention Programs in Children and Youth. Hamilton, Ontario: Effective Public Health Practice

Methods:

• A total of 21 relevant studies of physical activity interventions were identified.

Summary of Findings:

• Twelve of the twenty-one studies increased physical activity among the intervention group, and of these, only eight further studies were deemed to be of sound scientific methodology.
• Of the eight studies that demonstrated an increase in physical activity, only two studies measured and demonstrated lasting significant improvement in physical activity behavior.
• Most of these studies involved children in grades 3 to 6, and classroom or physical education teachers were usually the interveners. One study suggested that increased training and expertise by the interveners was linked to increased quality and quantity of physical activity.
• Six of the eight successful studies implemented an intervention focused on increasing physical activity along with a health education component directed toward healthy lifestyles.
• Interventions appeared to be more effective for boys than for girls, which may indicate that different interventions are required for males and females.
• Results of physical activity intervention studies are mixed; school-based studies are the most prevalently studied and show most successes.

Key Messages for Policy and Program Development:

• A health education component focusing on healthy lifestyles may be an important component of successful physical activity strategies. (1 )
• Physical activity interventions may result in modest effects as a result of being carried out over a too short period of time, or from other methodological weaknesses. (4)
• Different physical activity interventions may be needed for boys and girls (5,7)
• Increased training and expertise of physical activity interveners may be linked to increased quality and quantity of physical activity outcomes (6)
• Parent and family involvement may be an important component of physical activity interventions (1, 10)

Interventions to Reduce Physical Inactivity in Children and Youth

Ciliska, D.1 (2004).
Effectiveness of Physical Activity Enhancement and Obesity Prevention Programs in Children and Youth. Hamilton, Ontario: Effective Public Health Practice

Methods:

• Six community-based projects were found to be relevant between the period of 1999 to 2003.
• Several other clinic-based studies are identified as having positive results and showing promise for community-based interventions.

Summary of Findings:

• Four of the six interventions were school-based, one involved parents, and one study was an after-school recreation program (dance program).
• Five out of the six studies had at least one statistically significant outcome. Outcome measures included reducing sedentary behaviors, notably, television, video and videogame use.
• Overall, there were high retention rates in these studies (few participants "dropped out" of studies).
• Three studies used social cognitive theory as the theoretical basis for their study, one used health promotion concepts, and two studies did not state their theoretical framework.
• The small collection of studies gives support to the relevance and importance of developing and evaluating community-based strategies to reduce sedentary behavior.

Key Messages for Policy and Program Development:

• School-based interventions appear to be highly effective in reducing physical inactivity (9)
• Growing evidence suggests that focusing on reducing sedentary behavior is as effective as targeting increased physical activity (11, 12)
• Intervention targeting decreasing sedentary behavior may show higher compliance and adherence rates as compared to interventions targeting physical activity (12).

Environmental Interventions to Improve Nutrition and Increase Physical Activity in Children and Youth.

Micucci, S. (2004).
Effectiveness of Physical Activity Enhancement and Obesity Prevention Programs in Children and Youth. Hamilton, Ontario: Effective Public Health Practice Project.

Methods:

• Twenty-one studies met the relevance criteria.
• Most of the literature on environmental interventions to increase physical activity is observational (not true scientific design) and did not meet the criteria for this review. .

Summary of Findings:

• All twenty-one studies reviewed were school-based.
• Sixteen studies included an environmental component mixed with other components (i.e. Curriculum intervention); five of the twenty-one programs offered an environmental-only component.
• Only one study was designed with the unique purpose of influencing physical activity levels.
• Most of the interventions were multi-component, and therefore it is not possible to isolate the benefit of the environmental component on physical activity levels. The environmental-only studies were generally categorized of being of poor scientific quality and findings were subsequently inconclusive.
• The author notes a lack of rigorous environmental interventions in the community setting.

Key Messages for Policy and Program Development:

• Interventions including both an educational component and an environmental component directed at raising physical activity levels appear to be the most effective at increasing physical activity.
• The barriers preventing children from actively commuting to school need to be addressed and removed. The main barriers are thought to be traffic danger and distance. (2, 3)