Odd-impact Loading Results in Increased Cortical Area and Moments of Inertia in Collegiate Athletes

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Purpose: The purpose of this study was to investigate tibial changes in volumetric bone mineral density and geometry that take place in athletes from pre- to post-season.
Methods: Female college athletes (n = 36) and ten controls recruited from the student population were included in the study. Participants had their left tibia scanned by pQCT at 4, 20, and 66 % of the overall length from the distal end before and after their competitive seasons. Subjects were divided into four groups: non-athlete (controls, n = 10), moderate-impact (cross-country runners, n = 13), high-impact (volleyball and basketball, n = 11), and odd-impact (soccer, n = 12).
Results Anterior–posterior and medial–lateral diameter increased at the 4 % site in control subjects. In the moderate-impact group, medial–lateral moment of inertia (MOI) increased by 1.2 ± 1.8 (mean ± SD) percent at the 20 % site. In high-impact group, anterior–posterior MOI increased by 1.6 ± 2.0 percent at the 66 % site. In odd-impact group, cortical area (1.4 ± 2.3 %) and cortical thickness (1.8 ± 2.8 %) increased at the 20 % site increased, as did the polar MOI (1.8 ± 2.2 %) at the 66 % site.
Conclusions Load-specific changes resulting in improved measures of bone strength take place in athletes during a competitive season. These changes may result in improved resistance to fractures and stress fractures.

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European Journal of Applied Physiology





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