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Predicting the bending properties of long bones: Insights from an experimental mouse model
Author(s) -
Peacock Sarah J.,
Coats Brittney R.,
Kirkland J. Kyle,
Tanner Courtney A.,
Garland Theodore,
Middleton Kevin M.
Publication year - 2018
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.23363
Subject(s) - bending , geometry , biomechanics , strain (injury) , morphometrics , bone density , structural engineering , orthodontics , medicine , mathematics , biology , anatomy , osteoporosis , engineering , fishery
Objectives Analyses of bone cross‐sectional geometry are frequently used by anthropologists and paleontologists to infer the loading histories of past populations. To address some underlying assumptions, we investigated the relative roles of genetics and exercise on bone cross‐sectional geometry and bending mechanics in three mouse strains: high bone density (C3H/He), low bone density (C57BL/6), and a high‐runner strain homozygous for the Myh4 Minimsc allele (MM). Methods and Materials Weanlings of each strain were divided into exercise (wheel) or control (sedentary) treatment groups for a 7‐week experimental period. Morphometrics of the femoral mid‐diaphysis and mechanical testing were used to assess both theoretical and ex vivo bending mechanics. Results Across all measured morphological and bending traits, we found relatively small effects of exercise treatment compared to larger and more frequent interstrain differences. In the exercised group, total distance run over the experimental period was not a predictor of any morphological or bending traits. Cross‐sectional geometry did not accurately predict bone response to loading. Discussion Results from this experimental model do not support hypothesized associations among extreme exercise, cross‐sectional geometry, and bending mechanics. Our results suggest that analysis of cross‐sectional geometry alone is insufficient to predict loading response, and questions the common assumption that cross‐sectional geometry differences are indicative of differential loading history.