Osteoporosis International

, 19:1445 | Cite as

Does a novel school-based physical activity model benefit femoral neck bone strength in pre- and early pubertal children?

  • H. M. Macdonald
  • S. A. Kontulainen
  • M. A. Petit
  • T. J. Beck
  • K. M. Khan
  • H. A. McKayEmail author
Original Article



The effects of physical activity on bone strength acquisition during growth are not well understood. In our cluster randomized trial, we found that participation in a novel school-based physical activity program enhanced bone strength acquisition and bone mass accrual by 2–5% at the femoral neck in girls; however, these benefits depended on teacher compliance with intervention delivery. Our intervention also enhanced bone mass accrual by 2–4% at the lumbar spine and total body in boys.


We investigated the effects of a novel school-based physical activity program on femoral neck (FN) bone strength and mass in children aged 9–11 yrs.


We used hip structure analysis to compare 16-month changes in FN bone strength, geometry and bone mineral content (BMC) between 293 children who participated in Action Schools! BC (AS! BC) and 117 controls. We assessed proximal femur (PF), lumbar spine (LS) and total body (TB) BMC using DXA. We compared change in bone outcomes between groups using linear regression accounting for the random school effect and select covariates.


Change in FN strength (section modulus, Z), cross-sectional area (CSA), subperiosteal width and BMC was similar between control and intervention boys, but intervention boys had greater gains in BMC at the LS (+2.7%, p = 0.05) and TB (+1.7%, p = 0.03) than controls. For girls, change in FN-Z tended to be greater (+3.5%, p = 0.1) for intervention girls than controls. The difference in change increased to 5.4% (p = 0.05) in a per-protocol analysis that included girls whose teachers reported 80% compliance.


AS! BC benefits bone strength and mass in school-aged children; however, our findings highlight the importance of accounting for teacher compliance in classroom-based physical activity interventions.


Bone mass Bone strength Children DXA Hip structure analysis Physical activity 



We thank the principals, teachers, parents and children from the Vancouver and Richmond School Districts for their support and participation in this research. We thank Leslie Bryant MacLean for her technical assistance with the DXA scanning and analysis, Lisa Semanick for training on the HSA program and Dr. Penny Brasher for statistical guidance. We are grateful to the BC Ministry of Health, 2010 Legacies Now, BC Ministry of Education and the Canadian Institutes of Health Research for funding support. Dr. McKay is a Michael Smith Foundation for Health Research (MSFHR) Senior Scholar.

Conflicts of interest



  1. 1.
    Morris FL, Naughton GA, Gibbs JL, Carlson JS, Wark JD (1997) Prospective ten-month exercise intervention in premenarcheal girls: positive effects on bone and lean mass. J Bone Miner Res 12:1453–1462PubMedCrossRefGoogle Scholar
  2. 2.
    Bradney M, Pearce G, Naughton G, Sullivan C, Bass S, Beck T, Carlson J, Seeman E (1998) Moderate exercise during growth in prepubertal boys: changes in bone mass, size, volumetric density, and bone strength: A controlled prospective study. J Bone Miner Res 13:1814–1821PubMedCrossRefGoogle Scholar
  3. 3.
    McKay HA, Petit MA, Schutz RW, Prior JC, Barr SI, Khan KM (2000) Augmented trochanteric bone mineral density after modified physical education classes: a randomized school-based exercise intervention study in prepubescent and early pubescent children. J Pediatr 136:156–162PubMedCrossRefGoogle Scholar
  4. 4.
    Heinonen A, Sievanen H, Kannus P, Oja P, Pasanen M, Vuori I (2000) High-impact exercise and bones of growing girls: a 9-month controlled trial. Osteoporos Int 11:1010–1017PubMedCrossRefGoogle Scholar
  5. 5.
    Fuchs RK, Bauer JJ, Snow CM (2001) Jumping improves hip and lumbar spine bone mass in prepubescent children: a randomized controlled trial. J Bone Miner Res 16:148–156PubMedCrossRefGoogle Scholar
  6. 6.
    Linden C, Ahlborg HG, Besjakov J, Gardsell P, Karlsson MK (2006) A school curriculum-based exercise program increases bone mineral accrual and bone size in prepubertal girls: two-year data from the pediatric osteoporosis prevention (POP) study. J Bone Miner Res 21:829–835PubMedCrossRefGoogle Scholar
  7. 7.
    Manske SL, Liu-Ambrose T, de Bakker PM, Liu D, Kontulainen S, Guy P, Oxland TR, McKay HA (2006) Femoral neck cortical geometry measured with magnetic resonance imaging is associated with proximal femur strength. Osteoporos Int 17:1539–1545PubMedCrossRefGoogle Scholar
  8. 8.
    Jarvinen TL, Sievanen H, Jokihaara J, Einhorn TA (2005) Revival of bone strength: the bottom line. J Bone Miner Res 20:717–720PubMedCrossRefGoogle Scholar
  9. 9.
    MacKelvie KJ, McKay HA, Petit MA, Moran O, Khan KM (2002) Bone mineral response to a 7-month randomized controlled, school-based jumping intervention in 121 prepubertal boys: associations with ethnicity and body mass index. J Bone Miner Res 17:834–844PubMedCrossRefGoogle Scholar
  10. 10.
    MacKelvie KJ, Petit MA, Khan KM, Beck TJ, McKay HA (2004) Bone mass and structure are enhanced following a 2-year randomized controlled trial of exercise in prepubertal boys. Bone 34:755–764PubMedCrossRefGoogle Scholar
  11. 11.
    MacKelvie KJ, McKay HA, Khan KM, Crocker PR (2001) A school-based exercise intervention augments bone mineral accrual in early pubertal girls. J Pediatr 139:501–508PubMedCrossRefGoogle Scholar
  12. 12.
    Petit MA, McKay HA, MacKelvie KJ, Heinonen A, Khan KM, Beck TJ (2002) A randomized school-based jumping intervention confers site and maturity-specific benefits on bone structural properties in girls: a hip structural analysis study. J Bone Miner Res 17:363–372PubMedCrossRefGoogle Scholar
  13. 13.
    MacKelvie KJ, Khan K, Petit MA, Janssen PA, McKay HA (2003) A school-based exercise intervention elicits substantial bone health benefits: A 2-year randomized controlled trial in girls. Pediatrics 112:e447–e452PubMedCrossRefGoogle Scholar
  14. 14.
    Naylor PJ, Macdonald HM, Zebedee JA, Reed KE, McKay HA (2006) Lessons learned from Action Schools! BC-An ‘active school’ model to promote physical activity in elementary schools. J Sci Med Sport 9:413–423PubMedCrossRefGoogle Scholar
  15. 15.
    Macdonald HM, Kontulainen SA, Khan KM, McKay HA (2007) Is a school-based physical activity intervention effective for increasing tibial bone strength in boys and girls? J Bone Miner Res 22:434–446PubMedCrossRefGoogle Scholar
  16. 16.
    McKay HA, MacLean L, Petit M, MacKelvie-O’Brien K, Janssen P, Beck T, Khan KM (2005) “Bounce at the Bell”: a novel program of short bouts of exercise improves proximal femur bone mass in early pubertal children. Br J Sports Med 39:521–526PubMedCrossRefGoogle Scholar
  17. 17.
    Umemura Y, Ishiko T, Yamauchi T, Kurono M, Mashiko S (1997) Five jumps per day increase bone mass and breaking force in rats. J Bone Miner Res 12:1480–1485PubMedCrossRefGoogle Scholar
  18. 18.
    Robling AG, Burr DB, Turner CH (2001) Recovery periods restore mechanosensitivity to dynamically loaded bone. J Exp Biol 204:3389–3399PubMedGoogle Scholar
  19. 19.
    Umemura Y, Sogo N, Honda A (2002) Effects of intervals between jumps or bouts on osteogenic response to loading. J Appl Physiol 93:1345–1348PubMedGoogle Scholar
  20. 20.
    Ministry of Education (2001-2002) Satisfaction Survey. Government of British Columbia, Victoria, BC. Available at Accessed January 12, 2003
  21. 21.
    Naylor P, Macdonald HM, Reed KE, McKay HA (2006) Action Schools! BC: A socio-ecological approach to modifying chronic disease risk factors in elementary school children. Prev Chronic Dis [serial online] Available at: Accessed May 20, 2006
  22. 22.
    Mirwald RL, Baxter-Jones AD, Bailey DA, Beunen GP (2002) An assessment of maturity from anthropometric measurements. Med Sci Sports Exerc 34:689–694PubMedCrossRefGoogle Scholar
  23. 23.
    Tanner JM (1978) Foetus into man. Harvard Press, CambridgeGoogle Scholar
  24. 24.
    Crocker PR, Bailey DA, Faulkner RA, Kowalski KC, McGrath R (1997) Measuring general levels of physical activity: preliminary evidence for the Physical Activity Questionnaire for Older Children. Med Sci Sports Exerc 29:1344–1349PubMedGoogle Scholar
  25. 25.
    Kowalski KC, Crocker PR, Faulkner RA (1997) Validation of the physical activity questionnaire for older children. Pediatr Exerc Sci 9:174–186Google Scholar
  26. 26.
    MacKelvie KJ, McKay HA, Khan KM, Crocker PR (2001) Lifestyle risk factors for osteoporosis in Asian and Caucasian girls. Med Sci Sports Exerc 33:1818–1824PubMedCrossRefGoogle Scholar
  27. 27.
    Barr SI (1994) Associations of social and demographic variables with calcium intakes of high school students. J Am Diet Assoc 94:260–266PubMedCrossRefGoogle Scholar
  28. 28.
    Hologic (2000) Hologic QDR series user’s guide. Hologic, Inc, Bedford, MAGoogle Scholar
  29. 29.
    Beck TJ, Ruff CB, Warden KE, Scott WW Jr, Rao GU (1990) Predicting femoral neck strength from bone mineral data. A structural approach. Invest Radiol 25:6–18PubMedCrossRefGoogle Scholar
  30. 30.
    Khoo BC, Beck TJ, Qiao QH, Parakh P, Semanick L, Prince RL, Singer KP, Price RI (2005) In vivo short-term precision of hip structure analysis variables in comparison with bone mineral density using paired dual-energy X-ray absorptiometry scans from multi-center clinical trials. Bone 37:112–121PubMedCrossRefGoogle Scholar
  31. 31.
    Bailey DA, McKay HA, Mirwald RL, Crocker PR, Faulkner RA (1999) A six-year longitudinal study of the relationship of physical activity to bone mineral accrual in growing children: The University of Saskatchewan Bone Mineral Accrual Study. J Bone Miner Res 14:1672–1679PubMedCrossRefGoogle Scholar
  32. 32.
    Kerry SM, Bland JM (1998) The intracluster correlation coefficient in cluster randomisation. BMJ 316:1455PubMedGoogle Scholar
  33. 33.
    Wears RL (2002) Advanced statistics: statistical methods for analyzing cluster and cluster-randomized data. Acad Emerg Med 9:330–341PubMedCrossRefGoogle Scholar
  34. 34.
    Donner A, Klar N (2000) Design and analysis of cluster randomized trials in health research. Arnold Publishers, LondonGoogle Scholar
  35. 35.
    Fox KR, Cooper A, McKenna J (2004) The school and promotion of children’s health-enhancing physical activity: Perspectives from the United Kingdom. J Sch Health 23:338–358Google Scholar
  36. 36.
    Hannan PJ, French SA, Himes JH, Fulkerson JA, Story M (2004) The review process fails to require appropriate statistical analysis of a group-randomized trial. Pediatrics 114:509–511PubMedCrossRefGoogle Scholar
  37. 37.
    McKay H, Tsang G, Heinonen A, MacKelvie K, Sanderson D, Khan KM (2005) Ground reaction forces associated with an effective elementary school based jumping intervention. Br J Sports Med 39:10–14PubMedCrossRefGoogle Scholar
  38. 38.
    Engsberg JR, Lee AG, Tedford KG, Harder JA (1993) Normative ground reaction force data for able-bodied and trans-tibial amputee children during running. Prosthet Orthot Int 17:83–89PubMedGoogle Scholar
  39. 39.
    Pittenger VM, McCaw ST, Thomas DQ (2002) Vertical ground reaction forces of children during one- and two-leg rope jumping. Res Q Exerc Sport 73:445–449PubMedGoogle Scholar
  40. 40.
    Milgrom C, Miligram M, Simkin A, Burr D, Ekenman I, Finestone A (2001) A home exercise program for tibial bone strengthening based on in vivo strain measurements. Am J Phys Med Rehabil 80:433–438PubMedCrossRefGoogle Scholar
  41. 41.
    Bass S, Delmas PD, Pearce G, Hendrich E, Tabensky A, Seeman E (1999) The differing tempo of growth in bone size, mass, and density in girls is region-specific. J Clin Invest 104:795–804PubMedCrossRefGoogle Scholar
  42. 42.
    Bradney M, Karlsson MK, Duan Y, Stuckey S, Bass S, Seeman E (2000) Heterogeneity in the growth of the axial and appendicular skeleton in boys: implications for the pathogenesis of bone fragility in men. J Bone Miner Res 15:1871–1878PubMedCrossRefGoogle Scholar
  43. 43.
    Beck T (2003) Measuring the structural strength of bones with dual-energy X-ray absorptiometry: principles, technical limitations, and future possibilities. Osteoporos Int 14(Suppl 5):81–88CrossRefGoogle Scholar
  44. 44.
    Forwood MR, Baxter-Jones AD, Beck TJ, Mirwald RL, Howard A, Bailey DA (2006) Physical activity and strength of the femoral neck during the adolescent growth spurt: A longitudinal analysis. Bone 38:576–583PubMedCrossRefGoogle Scholar

Copyright information

© International Osteoporosis Foundation and National Osteoporosis Foundation 2008

Authors and Affiliations

  • H. M. Macdonald
    • 1
  • S. A. Kontulainen
    • 2
  • M. A. Petit
    • 3
  • T. J. Beck
    • 4
  • K. M. Khan
    • 5
  • H. A. McKay
    • 1
    • 5
    Email author
  1. 1.Department of OrthopaedicsUniversity of British ColumbiaVancouverCanada
  2. 2.College of KinesiologyUniversity of SaskatchewanSaskatoonCanada
  3. 3.School of KinesiologyUniversity of MinnesotaMinneapolisUSA
  4. 4.Johns Hopkins Medical InstitutionsBaltimoreUSA
  5. 5.Department of Family Practice, Faculty of MedicineUniversity of British ColumbiaVancouverCanada

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