Effect of a general school-based physical activity intervention on bone mineral content and density: a cluster-randomized controlled trial

Meyer, Ursina; Romann, Michael; Zahner, Lukas; Schindler, Christian; Puder, Jardena J.; Kraenzlin, Marius; Rizzoli, Rene; Kriemler, Susi (2011). Effect of a general school-based physical activity intervention on bone mineral content and density: a cluster-randomized controlled trial Bone, 48(4), pp. 792-797. Elsevier 10.1016/j.bone.2010.11.018

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Background: Specific physical loading leads to enhanced bone development during childhood. A general physical activity program mimicking a real-life situation was successful at increasing general physical health in children. Yet, it is not clear whether it can equally increase bone mineral mass. We performed a cluster-randomized controlled trial in children of both gender and different pubertal stages to determine whether a school-based physical activity (PA) program during one school-year influences bone mineral content (BMC) and density (BMD), irrespective of gender. Methods: Twenty-eight 1st and 5th grade (6-7 and 11-12 year-old) classes were cluster randomized to an intervention (INT, 16 classes, n=297) and control (CON; 12 classes, n=205) group. The intervention consisted of a multi-component PA intervention including daily physical education with at least 10 min of jumping or strength training exercises of various intensities. Measurements included anthropometry, and BMC and BMD of total body, femoral neck, total hip and lumbar spine using dual-energy X-ray absorptiometry (DXA). PA was assessed by accelerometers and Tanner stages by questionnaires. Analyses were performed by a regression model adjusted for gender, baseline height and weight, baseline PA, post-intervention pubertal stage, baseline BMC, and cluster. Results: 275 (72%) of 380 children who initially agreed to have DXA measurements had also post-intervention DXA and PA data. Mean age of prepubertal and pubertal children at baseline was 8.7±2.1 and 11.1±0.6 years, respectively. Compared to CON, children in INT showed statistically significant increases in BMC of total body, femoral neck, and lumbar spine by 5.5%, 5.4% and 4.7% (all p<0.05), respectively, and BMD of total body and lumbar spine by 8.4% and 7.3% (both p<0.01), respectively. There was no gender *group, but a pubertal stage *group interaction consistently favoring prepubertal children.

Item Type:	Journal Article (Original Article)
Division/Institute:	Swiss Federal Institute of Sports Magglingen SFISM > EHSM - Leistungssport > Trainingswissenschaft
Name:	Meyer, Ursina; Romann, Michael0000-0003-4139-2955; Zahner, Lukas; Schindler, Christian; Puder, Jardena J.; Kraenzlin, Marius; Rizzoli, Rene and Kriemler, Susi
ISSN:	8756-3282
Publisher:	Elsevier
Language:	English
Submitter:	Service Account
Date Deposited:	04 Mar 2021 09:00
Last Modified:	21 Oct 2021 02:18
Publisher DOI:	10.1016/j.bone.2010.11.018
PubMed ID:	21167330
Uncontrolled Keywords:	Exercise Mechanical loading Children Growth and development Physical activity
ARBOR DOI:	10.24451/arbor.11029
URI:	https://arbor.bfh.ch/id/eprint/11029