title: Effects of physical activity interventions in youth. Review and synthesis.
abstract: BACKGROUND
  Physical inactivity has been identified as an important public health concern for youth. School and community settings can be important infrastructures for promoting physical activity (PA). This paper reviews studies of physical activity in school and community settings among preschool through college-aged persons to determine characteristics and effects of interventions. Studies in progress are included.
  
  
  METHODS
  Studies from 1980 to 1997 testing physical activity interventions in schools and community settings were identified by computerized search methods and reference lists of published reviews. Studies needed to have used a quantitative assessment of PA, used a comparison or control group, included participants who were preschool through college age, and be conducted in the United States or foreign school or community settings. Significance of effects was examined overall and for various types of interventions.
  
  
  RESULTS
  Twenty-two school-based studies were reviewed, 14 completed and 8 in progress. Three studies were in countries other than the United States. The 8 studies in progress were all in the United States. Only 7 community studies were reviewed, all in the United States. Four studies were in progress. Several community studies involved a high percentage of African-American or Hispanic youth and their families. Studies showing the best results used randomized designs, valid and reliable measurements, and more extensive interventions. Some follow-up results showed PA was sustained after interventions ended.
  
  
  CONCLUSIONS
  The collection of school and community studies is limited for several age groups with none below third grade and only three at college age. There are few community studies. The most is known about upper-elementary-age-students, including the first multicenter randomized trial to report significant results for increasing moderate to vigorous physical activity (MVPA) in physical education (PE) and increase vigorous PA outside of school. A number of older study designs were weak and assessments less than optimal, but studies in progress are stronger. Special attention is needed for girls, middle schools, and community settings for all youth. More objective assessments are needed for measuring PA outside of school and in younger children, since they cannot provide reliable self-report.
authors.affiliation: Division of Epidemiology and Clinical Applications, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892-7936, USA.
authors.forename: E J
authors.initials: EJ
authors.lastname: Stone
authors.forename: T L
authors.initials: TL
authors.lastname: McKenzie
authors.forename: G J
authors.initials: GJ
authors.lastname: Welk
authors.forename: M L
authors.initials: ML
authors.lastname: Booth
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American; D000367:Age Factors; D002648:Child; D015331:Cohort Studies; D003479:Curriculum; D015444:Exercise; D005260:Female; D006293:Health Promotion; D006630:Hispanic or Latino; D006801:Humans; D007899:Leisure Activities; D008297:Male; D010806:Physical Education and Training; D010809:Physical Fitness; D011634:Public Health; D011897:Random Allocation; D012106:Research; D012494:Sampling Studies; D012574:Schools; D014481:United States