Site and sex effects on tibia structure in runners and untrained people
Feldman, Sara and Capozza, Ricardo and Mortarino, Pablo and Reina, Paola and Ferretti, José Luis and Rittweger, Jörn and Cointry, Gustavo (2012) Site and sex effects on tibia structure in runners and untrained people. Medicine and Science in Sports and Exercise, 8, pp. 1580-1288. ISSN 0025-7990.
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PURPOSE: The purpose was to study the relationship between mechanical environment and bone structure by comparing the tibia in people with different physical activities. MATERIALS AND METHODS: Indicators of bone mass (bone mineral content), bone material "quality" (cortical volumetric mineral density (vBMD)), and diaphyseal design (endocortical and periosteal perimeters (EcPm and PoPm, respectively), cortical thickness (CtTh), circularity, and bending and torsion cross-sectional moments of inertia (CSMIs)) were determined in serial peripheral quantitative computed tomography scans taken at 5% steps of the tibia in 40 voluntary men and women age 25-40 yr who were either physically inactive or experienced distance runners (n = 10-12 per group). RESULTS: Bone mass and design indicators were higher in runner than in nonrunner men, with a variable effect size along the tibia. In the distal tibia, runners had enhanced bone mineral content and CtTh (resistance to compression), but EcPm, PoPm, circularity, and CSMI were unaffected. In the midshaft, CSMIs (resistance to bending/torsion) were enhanced in runners, whereas bone mass was unaffected. In the proximal third, effects were observed for CtTh, EcPm, and PoPm. In female runners, these benefits were restricted to CSMIs only. Cortical vBMD, naturally lower in men than in women, was reduced in runners of either sex. DISCUSSION: Results are coherent with previous findings in physically inactive people and with Frost's mechanostat theory. The observed group differences in cortical vBMD could reflect an increase in intracortical porosity (enhanced remodeling for damage repair), eventually compensated biomechanically by CSMI improvements. The sex specificity of exercise effects may suggest the interference by the endocrine environment. Results confirm that the mechanical environment is a strong determinant of regional tibia structure and suggest that the endocrine environment may reduce the effects of physical interventions on bone health in fertile women.
|Title:||Site and sex effects on tibia structure in runners and untrained people|
|Journal or Publication Title:||Medicine and Science in Sports and Exercise|
|In ISI Web of Science:||No|
|Page Range:||pp. 1580-1288|
|Keywords:||Exercise and bone, Osteopenia, Osteoporosis, Bone biomechanics, bone structure, bone strength|
|HGF - Research field:||Aeronautics, Space and Transport|
|HGF - Program:||Raumfahrt|
|HGF - Program Themes:||R FR - Forschung unter Weltraumbedingungen|
|DLR - Research area:||Raumfahrt|
|DLR - Program:||R FR - Forschung unter Weltraumbedingungen|
|DLR - Research theme (Project):||R - Vorhaben Integrative Studien|
|Institutes and Institutions:||Institute of Aerospace Medicine > Space Physiology|
|Deposited By:||Jörn Rittweger|
|Deposited On:||14 Sep 2012 12:00|
|Last Modified:||07 Feb 2013 19:44|
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