The Influence of Exercise on the 3D distribution of Cortical and Trabecular Bone across the Proximal Femur: The HipHop Study
Biomechanics and Physical Activity
Sarcopenia, Muscle and Falls
Oral Presentations, Presentation Number: 1013
Session: Concurrent Orals: Falls, Frailty and Fractures
Friday, September 12, 2014 1:45 PM - 2:00 PM, George R. Brown Convention Center, Grand Ballroom A
* Sarah Allison, Loughborough University, , UNITED KINGDOM, , UNITED KINGDOM, Andrew Gee, University of Cambridge, Carol Tonkin, University of Cambridge, Winston Rennie, University Hospitals of Leicester, Jonathan Folland, Loughborough University, Greg Summers, Derby Hospitals NHS Foundation Trust, , AF
Regular exercisers have a lower fracture risk, despite exercise having only modest effects on aBMD. This discrepancy may be explained by exercise producing localised structural changes that are not captured by aBMD. We previously demonstrated that regular, but brief, multidirectional hopping exercise increased BMC at the femoral neck in the exercise leg (EL) versus the control leg (CL) of older men (The HipHop Study). The aim of the present study was to determine the distribution of cortical mass, thickness and density changes across the entire proximal femur, using the cortical bone mapping technique.
Fifty, healthy older men had hip QCT scans taken at baseline and after one year of performing short, daily bouts of single-legged hopping exercises (x50 multidirectional hops per session on the randomly allocated leg). Cortical bone mapping identified thickness, mass and density and nearby trabecular density distributions on each femur, which was then registered to an average femur. Statistical parametric mapping was used to identify changes of these parameters over time in the exercise leg (EL) and control leg (CL), and also significant differences between legs. Results were displayed as a 3D colour map over the surface of the proximal femurs. All hip QCT scans and map analyses were blinded to the leg allocation.
Of the fifty men that participated in the study, thirty-four (age 70±4 years) exercised for 12-months, attending 92±9% of prescribed exercise sessions. Throughout the femur, cortical mass increased significantly more in the EL (+2.7%) compared to the CL (+1.6%); P=0.0019, but substantially larger changes (over 6%) were evident at localised regions of the femoral neck and shaft (Figure 1). Trabecular density also increased noticeably more in the EL (+6.4) versus CL (+4.5%); P=0.0127, with the inferior region of the femoral neck increasing by over 12% with exercise. Cortical density increased in both the EL (+1.8%, P=0.0001) and the CL (+1.6%, P=0.0013), whereas the cortical thickness changes (EL +0.5%; CL -0.2%; P=0.1358) were not statistically significant.
Our findings show that brief bouts of single-legged hopping exercises can significantly increase cortical mass and trabecular density over a relatively short time frame, at regions of the femoral neck that may be important to structural integrity. These exercise induced changes were localised rather than being evenly distributed across the proximal femur.
G. Treece, Listed as inventor on a patent application related to the cortical bone mapping technique.: Other.
* Presenting Authors(s):
Sarah Allison, Loughborough University