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School-based interventions modestly increase physical activity and cardiorespiratory fitness but are least effective for youth who need them most: an individual participant pooled analysis of 20 controlled trials
  1. Timothy Bryan Hartwig1,
  2. Taren Sanders2,
  3. Diego Vasconcellos2,
  4. Michael Noetel3,
  5. Philip D Parker2,
  6. David Revalds Lubans4,
  7. Susana Andrade5,
  8. Manuel Ávila-García6,
  9. John Bartholomew7,
  10. Sarahjane Belton8,
  11. Naomi E Brooks9,
  12. Anna Bugge10,
  13. Iván Cavero-Redondo11,
  14. Lars Breum Christiansen12,
  15. Kristen Cohen13,
  16. Tara Coppinger14,
  17. Sindre Dyrstad15,
  18. Vanessa Errisuriz16,
  19. Stuart Fairclough17,
  20. Trish Gorely18,
  21. Francisco Javier Huertas-Delgado6,
  22. Johann Issartel8,
  23. Susi Kriemler19,
  24. Silje Eikanger Kvalø15,
  25. Pedro Marques-Vidal20,
  26. Vicente Martinez-Vizcaino11,
  27. Niels Christian Møller21,
  28. Colin Moran9,
  29. John Morris22,
  30. Mary Nevill22,
  31. Angélica Ochoa-Avilés23,
  32. Mai O'Leary14,
  33. Louisa Peralta24,
  34. Karin A Pfeiffer25,
  35. Jardena Puder26,
  36. Andrés Redondo-Tébar27,
  37. Lorraine B Robbins28,
  38. Mairena Sanchez-Lopez11,
  39. Jakob Tarp29,
  40. Sarah Taylor30,
  41. Pablo Tercedor6,
  42. Mette Toftager31,
  43. Emilio Villa-González6,
  44. Niels Wedderkopp32,
  45. Kathryn Louise Weston33,
  46. Zenong Yin34,
  47. Zhou Zhixiong35,
  48. Chris Lonsdale2,
  49. Borja del Pozo Cruz2
  1. 1 School of Behavioural and Health Sciences, Australian Catholic University, Strathfield, New South Wales, Australia
  2. 2 Institute for Positive Psychology and Education, Australian Catholic University Faculty of Health Sciences, North Sydney, New South Wales, Australia
  3. 3 School of Behavioural and Health Sciences, Australian Catholic University, Brisbane, Queensland, Australia
  4. 4 Priority Research Centre for Physical Activity and Nutrition, University of Newcastle, Newcastle, New South Wales, Australia
  5. 5 Faculty of Philosophy, Letters and Education Sciences, University of Cuenca, Cuenca, Azuay, Ecuador
  6. 6 Department of Physical Education and Sports, University of Granada, Granada, Andalucía, Spain
  7. 7 Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas, USA
  8. 8 School of Health and Human Performance, Dublin City University, Dublin, Ireland
  9. 9 Faculty of Health Sciences and Sport, University of Stirling, Stirling, Stirling, UK
  10. 10 Department of Midwifery, Physiotherapy, Occupational Therapy and Psychomotor Therapy Faculty of Health, University of Copenhagen, Kobenhavn, Denmark
  11. 11 Social and Health Care Research Center, Universidad de Castilla-La Mancha, Cuenca, Spain
  12. 12 Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
  13. 13 Priority Research Centre for Physical Activity and Nutrition, The University of Newcastle Faculty of Science, Callaghan, New South Wales, Australia
  14. 14 Department of Sport, Leisure and Childhood Studies, Cork Institute of Technology, Cork, Cork, Ireland
  15. 15 Department of Public Health, University of Stavanger, Stavanger, Norway
  16. 16 Latino Research Institute, University of Texas at Austin, Austin, Texas, USA
  17. 17 Department of Sport and Physical Activity, Edge Hill University, Ormskirk, Lancashire, UK
  18. 18 Department of Nursing and Midwifery, University of the Highlands and Islands Inverness College, Inverness, Highland, UK
  19. 19 Epidemiology, Biostatistics and Prevention Institute, University of Zürich, Zurich, ZH, Switzerland
  20. 20 Department of Medicine, Internal Medicine, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
  21. 21 Department of Sport Sciences and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
  22. 22 Department of Sport Science, Nottingham Trent University, Nottingham, Nottinghamshire, UK
  23. 23 Department of Biosciences, Faculty of Chemistry, University of Cuenca, Cuenca, Azuay, Ecuador
  24. 24 Sydney School of Education and Social Work, University of Sydney - Camperdown and Darlington Campus, Sydney, New South Wales, Australia
  25. 25 Department of Kinesiology, Michigan State University, East Lansing, Michigan, USA
  26. 26 Department Woman-Mother-Child, Lausanne University Hospital, Lausanne, Switzerland
  27. 27 Health and Social Research Center, Universidad de Castilla-La Mancha, Ciudad Real, Castilla-La Mancha, Spain
  28. 28 Nursing Education and Research, Michigan State University, East Lansing, Michigan, USA
  29. 29 Department of Sports Medicine, Norwegian School ofSports Sciences, Oslo, Norway
  30. 30 Physical Activity Exchange, Research Institute for Sport andExercise Sciences, Liverpool John Moores University, Liverpool, UK
  31. 31 National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark
  32. 32 Orthopedic Department, Hospital Of Southwestern Jutland, Esbjerg, Denmark
  33. 33 School of Applied Sciences Sighthill Campus, Edinburgh Napier University, Edinburgh, UK
  34. 34 Department of Public Health, The University of Texas at San Antonio, San Antonio, Texas, USA
  35. 35 Institute for Sport Performance and Health Promotion, Capital University of Sports and Physical Education, Beijing, China
  1. Correspondence to Dr Timothy Bryan Hartwig, School of Behavioural and Health Sciences, Australian Catholic University, Strathfield, New South Wales, Australia; timothy.hartwig{at}


Objectives To determine if subpopulations of students benefit equally from school-based physical activity interventions in terms of cardiorespiratory fitness and physical activity. To examine if physical activity intensity mediates improvements in cardiorespiratory fitness.

Design Pooled analysis of individual participant data from controlled trials that assessed the impact of school-based physical activity interventions on cardiorespiratory fitness and device-measured physical activity.

Participants Data for 6621 children and adolescents aged 4–18 years from 20 trials were included.

Main outcome measures Peak oxygen consumption (VO2Peak mL/kg/min) and minutes of moderate and vigorous physical activity.

Results Interventions modestly improved students’ cardiorespiratory fitness by 0.47 mL/kg/min (95% CI 0.33 to 0.61), but the effects were not distributed equally across subpopulations. Girls and older students benefited less than boys and younger students, respectively. Students with lower levels of initial fitness, and those with higher levels of baseline physical activity benefitted more than those who were initially fitter and less active, respectively. Interventions had a modest positive effect on physical activity with approximately one additional minute per day of both moderate and vigorous physical activity. Changes in vigorous, but not moderate intensity, physical activity explained a small amount (~5%) of the intervention effect on cardiorespiratory fitness.

Conclusions Future interventions should include targeted strategies to address the needs of girls and older students. Interventions may also be improved by promoting more vigorous intensity physical activity. Interventions could mitigate declining youth cardiorespiratory fitness, increase physical activity and promote cardiovascular health if they can be delivered equitably and their effects sustained at the population level.

  • individual participant data (IPD)
  • cardiorespiratory fitness
  • moderate to vigorous physical activity
  • youth
  • school-based physical activity intervention
  • peak oxygen consumption

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  • CL and BdPC are joint senior authors.

  • Twitter @mnoetel, @sjbelton, @PhysActivityEd, @DrMoran, @BorjadelPozoCr1

  • Correction notice This article has been corrected since it published Online First. The third author's name has been corrected and affiliation 23 has been added.

  • Contributors TBH, TS, DV, MN, PP, DRL, CL and BdPC contributed to the design of this pooled study. CL, PP and BdPC conceptualised the design of the present analysis and analysed the data. TBH obtained and harmonised raw data from lead investigators of eligible studies. TBH, TS, MN, PP, CL and BdPC wrote the first draft of the manuscript. TBH, TS, MN, PP, CL and BdPC had full access to the data in the study and can take responsibility for the integrity of the data and the accuracy of the data analysis. TBH, CL and BdPC are the guarantors. All other authors not specifically mentioned contributed raw data (data acquisition) for the pooled analysis and made important intellectual contributions by critically revising the study protocol, manuscript drafts and the final submitted manuscript. All authors agree to being accountable for all aspects of the work related to the accuracy or integrity of any part of the work. The corresponding author (TBH) attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.