![]() Moreover, studies have shown that beneficial bone adaptation can be observed through exercise even in older people 8 and can help in arresting the attenuation of bone strength due to age-related bone loss 9. This was observed in retired (>60 years) ice-hockey and soccer players as reduced fracture risk, in comparison to age matched controls, despite some loss of exercise-induced gain in bone 7. Thus, beneficial geometric adaptations accrued during adolescence and young adulthood may have lasting benefits in senescence despite associated bone loss 6. However, it is known that the exercise-induced bone thickening during growth occurs through new bone formation on the periosteal bone surface, while age-related bone loss takes place at the endocortical bone surface 5. While loading stimuli have the most pronounced effect in adolescence 3, their effectiveness in stimulating an adaptation decreases after bone reaches maturity 4. ![]() Thus, consistent loading in specific directions, such as physical training of athletes over a long period of time, can induce corresponding local adaptations in the cortical geometry 1, 2. The cortical geometry at the proximal femur consequently reflects the most robust construction adapted for the specific loading it habitually experiences (e.g., locomotion and physical activity). The ability of the femur to withstand these loads is achieved through adaptive processes that modulate its morphology and composition. In humans, the femur is indispensable for locomotion and load-bearing functions within a large range of motion under potentially high load magnitudes and impacts. This results in a constrained envelope of loading directions that a particular load bearing bone can experience during common habitual movements. The position of the bone and its function within the skeletal frame limits its range of motion through linkages between bones, joints and muscle attachments. With the aid of group-wise and composite-group maps, proximal femur regions affected by specific loading groups were identified with a high degree of spatial localisation.īone is an adaptive hard tissue which, among its other characteristics, is designed to be robust against physiological loads. Statistical inferences over the surfaces were made by contrasting the athlete groups with the controls through statistical parametric mapping. Subsequently, the group-wise distribution of two mechanically relevant features was studied – cortical thickness and surface principal strains (simulation results of a sideways fall). This is implemented through a multi-parametrisation approach to detect surface features and to overcome the issue of inconsistency in the anatomical extent present in the data. The procedure leverages the invariance of the conformal mapping method to isometric shape differences to align surfaces in the 2D parametric domain, to produce dense correspondences across an isotopological set of surfaces. A femur specific Ricci-flow based conformal mapping procedure was developed for establishing correspondence among the periosteal surfaces. In this study, 3D distribution of features in the proximal femur of 91 female athletes (5 exercise loading groups representing habitual loading) is contrasted with 20 controls. The causal relationship between habitual loading and adaptive response in bone morphology is commonly explored by analysing the spatial distribution of mechanically relevant features.
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