Daily school physical activity (PA) improves musculoskeletal traits. This study evaluates whether the benefits remain 4 years after the intervention. We followed 45 boys and 36 girls who had had 40 min PA/school day during the nine compulsory school years and 21 boys and 22 girls who had had 60 min PA/school week (reference), with measurements at baseline and 4 years after the program terminated. Bone mineral content (BMC; g) and bone mineral density (BMD; g/cm²) were measured by dual-energy X-ray absorptiometry and knee flexion peak torque relative to total body weight (PT_flexTBW) at a speed of 180 degrees/second with a computerized dynamometer. Group differences are presented as mean differences (adjusted for sex and duration of follow-up period) with 95% confidence intervals. The total gain bone mass [mean difference in spine BMC +32.0 g (14.6, 49.4) and in arms BMD of +0.06 g/cm² (0.02, 0.09)] and gain in muscle strength [mean difference in PT_flex180TBW +12.1 (2.0, 22.2)] were greater in the intervention than in the control group. There are still 4 years after the intervention indications of benefits in both bone mass and muscle strength gain. Daily school PA may counteract low bone mass and inferior muscle strength in adult life. ClinicalTrials.gov.NCT000633828 retrospectively registered 2008-11-03

日常学校体育活动 (PA) 可改善肌肉骨骼特征。本研究评估了干预后 4 年的益处是否仍然存在。我们跟踪了 45 名男孩和 36 名女孩，他们在 9 个义务教育学年期间进行了 40 分钟的 PA/学校日，以及 21 名男孩和 22 名女孩，他们进行了 60 分钟的 PA/学校周（参考），在基线和 4 年后进行了测量程序终止。骨矿物质含量（BMC；g）和骨矿物质密度（BMD；g/cm ²）通过双能 X 射线骨密度仪和相对于总体重的膝关节屈曲峰值扭矩（PT _flexTBW) 以 180 度/秒的速度使用计算机测功机。组间差异表示为平均差异（根据性别和随访时间进行调整），置信区间为 95%。总骨量增加 [脊柱 BMC +32.0 g (14.6, 49.4) 和手臂 BMD 的平均差异为 +0.06 g/cm ² (0.02, 0.09)] 和肌肉力量增加 [PT _flex180 TBW 的平均差异 +12.1 (2.0, 22.2)] 干预组高于对照组。干预后仍有 4 年的迹象表明对骨量和肌肉力量的增加都有好处。每日学校 PA 可以抵消成年生活中的低骨量和较差的肌肉力量。ClinicalTrials.gov. NCT000633828 追溯注册 2008-11-03