Resumen: Research in bone health during childhood is limited and important to prevent future diseases, particularly, osteoporosis. Bone parameters using DXA and pQCT in 295 Spanish children were evaluated and we found a benefit of meeting the World Health Organization physical activity recommendations in bone composition in childhood. Purpose To investigate the association between physical activity (PA) and bone health in a Spanish paediatric cohort, considering the influence of meeting/not meeting the current World Health Organization (WHO) PA recommendations and to elucidate if there are differences between boys and girls. Methods In a cohort of children born in the region of Aragon (Spain) in 2009, followed until the age of 7 years, bone parameters were assessed using dual-energy X-ray absorptiometry (DXA) (whole body scan) and peripheral quantitative computed tomography (pQCT) (tibia scanned at the 8% (distal) and 38% (diaphyseal) of the total tibia length) in 295 7-year-old children (154 boys) in the last evaluation performed between 2016 and 2017. PA was assessed using GT3X Actigraph accelerometers. Results Boys had significantly higher areal bone mineral density (aBMD), higher total bone mineral content (BMC) at the diaphyseal site and higher trabecular BMC and vBMD, and higher total bone area at the distal site than girls (p<0.01 for all of them). Both boys and girls complying with the WHO PA recommendations had significantly higher trabecular BMC than their inactive counterparts. Conclusions Meeting WHO PA recommendations has a beneficial effect in bone composition in childhood both in boys and in girls. Idioma: Inglés DOI: 10.1007/s00198-021-06256-z Año: 2021 Publicado en: OSTEOPOROSIS INTERNATIONAL 33, 5 (2021), 1017–1026 ISSN: 0937-941X Factor impacto JCR: 5.071 (2021) Categ. JCR: ENDOCRINOLOGY & METABOLISM rank: 46 / 147 = 0.313 (2021) - Q2 - T1 Factor impacto CITESCORE: 7.6 - Medicine (Q1)