title: Physical activity positively predicts bone architecture and bone strength in adolescent males and females.
abstract: OBJECTIVE
  Physical activity (PA) has positive effects on bone accrual and geometry in children during growth. However, we do not know how PA influences adaptations in bone architecture during growth. We evaluated the contribution of PA to bone density, architecture and strength in adolescents.
  
  
  METHODS
  We used HR-pQCT (XtremeCT, Scanco Medical) to assess cross-sectional moments of inertia [Imin, Imax (mm⁴)], total bone density (Tt.Dn, mg HA/cm³), total bone area (Tt.Ar, mm²), cortical bone density (Ct.Dn, mg HA/cm³), cortical thickness (Ct.Th, μm), trabecular bone density (Tb.Dn, mg HA/cm³), trabecular number (Tb.N, mm⁻¹) and trabecular thickness (Tb.Th, μm) at the distal tibia in 146 male and 132 female participants (15-20 years). We evaluated the contribution of impact loading PA (ImpactPA) and non-impact loading PA (NoimpactPA) on bone (p < 0.05).
  
  
  RESULTS
  ImpactPA explained 10% of variance in Imin (p = 0.000), and 12% of variance in Imax (p = 0.000) in male participants. In male participants, ImpactPA explained 6% of variance in Tt.Ar (p = 0.003). In female participants, ImpactPA explained 4% of variance in Tt.Dn (p = 0.011), 5% of variance in Tb.Dn (p = 0.004) and 8% of variance in Tb.N (p = 0.001).
  
  
  CONCLUSIONS
  Our findings suggest that ImpactPA is significantly associated with bone architecture and bone strength in adolescent males and females.
authors.affiliation: Department of Orthopaedics, University of British Columbia, BC, Canada. heather.mckay@ubc.ca
authors.forename: Heather
authors.initials: H
authors.lastname: McKay
authors.forename: Danmei
authors.initials: D
authors.lastname: Liu
authors.forename: Deetria
authors.initials: D
authors.lastname: Egeli
authors.forename: Steven
authors.initials: S
authors.lastname: Boyd
authors.forename: Melonie
authors.initials: M
authors.lastname: Burrows
mesh_terms: D000293:Adolescent; D041923:Adolescent Development / Q000502:physiology*; D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000033:anatomy & histology* / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D011795:Surveys and Questionnaires