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The Influence of High‐Impact Exercise on Cortical and Trabecular Bone Mineral Content and 3D Distribution Across the Proximal Femur in Older Men: A Randomized Controlled Unilateral Intervention
Author(s) -
Allison Sarah J,
Poole Kenneth E S,
Treece Graham M,
Gee Andrew H,
Tonkin Carol,
Rennie Winston J,
Folland Jonathan P,
Summers Gregory D,
BrookeWavell Katherine
Publication year - 2015
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1002/jbmr.2499
Subject(s) - medicine , femoral neck , femur , trochanter , cortical bone , greater trochanter , bone mineral , quantitative computed tomography , bone density , statistical parametric mapping , osteoporosis , anatomy , surgery , radiology , magnetic resonance imaging
Regular exercisers have lower fracture risk, despite modest effects of exercise on bone mineral content (BMC). Exercise may produce localized cortical and trabecular bone changes that affect bone strength independently of BMC. We previously demonstrated that brief, daily unilateral hopping exercises increased femoral neck BMC in the exercise leg versus the control leg of older men. This study evaluated the effects of these exercises on cortical and trabecular bone and its 3D distribution across the proximal femur, using clinical CT. Fifty healthy men had pelvic CT scans before and after the exercise intervention. We used hip QCT analysis to quantify BMC in traditional regions of interest and estimate biomechanical variables. Cortical bone mapping localized cortical mass surface density and endocortical trabecular density changes across each proximal femur, which involved registration to a canonical proximal femur model. Following statistical parametric mapping, we visualized and quantified statistically significant changes of variables over time in both legs, and significant differences between legs. Thirty‐four men aged mean (SD) 70 (4) years exercised for 12‐months, attending 92% of prescribed sessions. In traditional regions of interest, cortical and trabecular BMC increased over time in both legs. Cortical BMC at the trochanter increased more in the exercise than control leg, whereas femoral neck buckling ratio declined more in the exercise than control leg. Across the entire proximal femur, cortical mass surface density increased significantly with exercise (2.7%; p < 0.001), with larger changes (> 6%) at anterior and posterior aspects of the femoral neck and anterior shaft. Endocortical trabecular density also increased (6.4%; p < 0.001), with localized changes of > 12% at the anterior femoral neck, trochanter, and inferior femoral head. Odd impact exercise increased cortical mass surface density and endocortical trabecular density, at regions that may be important to structural integrity. These exercise‐induced changes were localized rather than being evenly distributed across the proximal femur. © 2015 American Society for Bone and Mineral Research.