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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.


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Authors

Allison, Sarah J 
Poole, Kenneth ES 
Treece, Graham M 
Gee, Andrew H 
Tonkin, Carol 

Abstract

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.

Description

Keywords

COMPUTATIONAL ANATOMY, COMPUTED TOMOGRAPHY, EXERCISE, HIP FRACTURE, MALES, Absorptiometry, Photon, Aged, Aged, 80 and over, Biomechanical Phenomena, Bone Density, Bone and Bones, Exercise, Exercise Therapy, Femur, Femur Neck, Hip Fractures, Humans, Imaging, Three-Dimensional, Male, Radiographic Image Interpretation, Computer-Assisted, Tomography, X-Ray Computed

Journal Title

J Bone Miner Res

Conference Name

Journal ISSN

0884-0431
1523-4681

Volume Title

30

Publisher

Oxford University Press (OUP)
Sponsorship
Cambridge University Hospitals NHS Foundation Trust (CUH) (146281)
Arthritis Research Uk (None)
National Osteoporosis Society (112/270)
Addenbrooke's Charitable Trust (ACT) (#9313)
This research was financially supported by a National Osteoporosis Innovative Award, Medical Research Council UK Interdisciplinary Bridging Award, and a Loughborough University Scholarship. KESP acknowledges support of the Cambridge NIHR Biomedical Research Centre.