PURPOSE: Most pediatric physical activity and bone health research has focused on the period immediately around puberty; few have addressed bone structural strength outcomes. This study assessed the magnitude and consistency of the longitudinal relationships between device-measured vigorous-intensity physical activity (VPA) and structural bone strength outcomes across adolescence to emerging adulthood. METHODS: Participants with 3 to 5 bone scans between the age of 11 and 19 years were studied (N = 439, 220 females, 1838 records). Dual-energy X-ray absorptiometry scans of the hip (hip structural analysis) and peripheral quantitative computed tomography scans of the tibia were obtained. Outcomes included femoral neck section modulus, femoral neck cross-sectional area, tibial Bone Strength Index, and tibial torsion strength (polar Strength Strain Index). Sex-specific bone mixed growth models were developed using biological age (chronological age - age at peak height velocity) as the time variable, and height, weight, and device-measured VPA as time-varying covariates. Models also included the VPA-biological age interaction. RESULTS: Individual-centered VPA and the VPA-biological age interaction were significantly, positively associated (P < .05) with Bone Strength Index, polar Strength Strain Index, section modulus, and cross-sectional area in males and females, indicating accumulative effects of VPA throughout maturation and beyond. CONCLUSION: Bone remains responsive to the mechanical loading of physical activity throughout adolescence and into emerging adulthood. Attention should be placed on promoting bone-strengthening physical activity after the prepubertal years when adult exercise patterns are likely formed.
PURPOSE: Most pediatric physical activity and bone health research has focused on the period immediately around puberty; few have addressed bone structural strength outcomes. This study assessed the magnitude and consistency of the longitudinal relationships between device-measured vigorous-intensity physical activity (VPA) and structural bone strength outcomes across adolescence to emerging adulthood. METHODS:Participants with 3 to 5 bone scans between the age of 11 and 19 years were studied (N = 439, 220 females, 1838 records). Dual-energy X-ray absorptiometry scans of the hip (hip structural analysis) and peripheral quantitative computed tomography scans of the tibia were obtained. Outcomes included femoral neck section modulus, femoral neck cross-sectional area, tibial Bone Strength Index, and tibial torsion strength (polar Strength Strain Index). Sex-specific bone mixed growth models were developed using biological age (chronological age - age at peak height velocity) as the time variable, and height, weight, and device-measured VPA as time-varying covariates. Models also included the VPA-biological age interaction. RESULTS: Individual-centered VPA and the VPA-biological age interaction were significantly, positively associated (P < .05) with Bone Strength Index, polar Strength Strain Index, section modulus, and cross-sectional area in males and females, indicating accumulative effects of VPA throughout maturation and beyond. CONCLUSION: Bone remains responsive to the mechanical loading of physical activity throughout adolescence and into emerging adulthood. Attention should be placed on promoting bone-strengthening physical activity after the prepubertal years when adult exercise patterns are likely formed.
Authors: C M Weaver; C M Gordon; K F Janz; H J Kalkwarf; J M Lappe; R Lewis; M O'Karma; T C Wallace; B S Zemel Journal: Osteoporos Int Date: 2016-02-08 Impact factor: 4.507
Authors: Adam D G Baxter-Jones; Robert A Faulkner; Mark R Forwood; Robert L Mirwald; Donald A Bailey Journal: J Bone Miner Res Date: 2011-08 Impact factor: 6.741
Authors: Kathleen F Janz; Elena M Letuchy; Trudy L Burns; Julie M Eichenberger Gilmore; James C Torner; Steven M Levy Journal: Br J Sports Med Date: 2014-05-16 Impact factor: 13.800