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    ASBMR 2012 Annual Meeting

    Effects of a Specialized School Physical Education Program on Bone Structure and Strength: A 4-year Cluster Randomised Controlled Trial

    Categories:
     Bone Acquisition and Pediatric Bone Disease
     Osteoporosis - Treatment (Clinical)

    Oral Presentations, Presentation Number: 1070
    Session: Concurrent Oral Session 12: Bone Acquisition and Pediatric Bone Disease
    Saturday, October 13, 2012 3:00 PM - 3:15 PM, Minneapolis Convention Center, Room 200DE

    * Robin Daly, Centre for Physical Activity and Nutrition Research, Deakin University, AUS, Gaele Ducher, Centre for Physical Activity and Nutrition Research, Deakin University, Australia, Ross Cunningham, Fenner School of Environment and Society, Australian National University, Australia, Briony Hill, Centre for Physical Activity and Nutrition Research, Deakin University, Australia, Rohan Telford, Centre for Research and Action in Public Health, Department of Health, University of Canberra, Australia, Prisca Eser, Swiss Cardiovascular Centre Bern, University Hospital (Inselspital), Switzerland, Geraldine Naughton, Centre of Physical Activity Across the Lifespan, Australian Catholic University, Australia, Markus Seibel, Bone Research Program, ANZAC Research Institute, University of Sydney, AUSTRALIA, Ahmad Javaid, The Canberra Hospital, Australia, Richard Telford, Clinical Trials Unit, The Canberra Hospital and Medical School, Australian National University, Australia

    Physical activity programs incorporating specific weight-bearing exercises have proven effective for enhancing bone mineral accrual during growth, but the effects of more generalized school-based physical education (PE) on bone health remains unclear. In addition, few long-term studies have used pQCT to characterize changes in bone strength and its determinants (bone structure and volumetric BMD) in response to exercise during growth. This study investigated the effects of a specialist taught school PE program on bone mass, structure and strength and muscle mass and size in primary school aged children. This was a 4-year cluster RCT involving 365 boys and 362 girls in grade 2 aged 8 (SD 0.3) years from 29 primary schools in Canberra, Australia. All children received 150 min/week PE from classroom teachers but in 13 schools 100 min/week was replaced by two specialized PE classes that emphasized more vigorous exercise and games combined with static and dynamic postural activities involving muscle strength and function. Measurements in grades 2, 4, and 6 included DXA total body BMC and lean mass (LM), pQCT volumetric BMD, structure and strength at the radius and tibia (4% and 66% sites) and muscle CSA and pubertal development (Tanner stage). In girls, the 4-year gains in cortical area at the mid-radius and mid-tibia were on average, 9.6% (P<0.05) and 5.0% (P=0.08) greater in those who received the specialized compared to common-practice PE, with the relative increase being most apparent in the last 2 yrs. These results were independent of bone length, weight, pubertal status and the random effect of school. In boys, the only positive effect of the specialized PE was on cortical vBMD at the mid-tibia (2.4% vs 1.3%, P<0.05). However, neither of these benefits translated into significant improvements in bone strength in the specialized PE group. There was also no evidence of any beneficial effects of specialized PE on trabecular vBMD at the distal radius or tibia or whole body LM or regional muscle CSA after 4-yrs. In conclusion, this study showed that generalized PE conducted twice weekly by specialist physical educators through grades 3-6 (age 8-12) of primary school can have some positive effects on cortical area and density, but these benefits did not translate into significant improvements in bone strength. This suggests that more specific bone loading activities may need to be incorporated into PE classes to maximize skeletal benefits during growth.

    Disclosures: None

    * Presenting Authors(s): Robin Daly, Centre for Physical Activity and Nutrition Research, Deakin University, AUS