Adaptation of bone to exercise assessed by MRI.

运动已被认为是改善或维持骨骼结构能力的一种策略。与以前使用双能X射线吸收法(DXA)进行的密度测量分析报告的面骨密度(a BMD；每投影面积的骨矿含量)随运动而增加不同，使用外周定量计算机断层扫描(PQCT)的研究显示，成年人骨的力学性能对运动的响应与体积骨密度(vBMU；单位体积中的骨矿含量)的负变化有关。此外，pQCT研究显示，训练组的骨膜面积和皮质面积显著增加，皮质厚度也增加。因此，长期体育锻炼对骨骼力学性能的改善与几何适应有关，而与vBMD无关。由于受到辐射的影响，pQCT的研究仅限于选定的骨切片，尚未对人体的整体骨结构进行研究。本研究对运动员胫骨和跟骨的整体骨结构进行了MRI分析。此外，在Silico中对骨的力学性能进行了模拟。

Exercise has been proposed as one strategy for improving or maintaining the structural competence of bone. In contrast with previous densitometric analysis using dual energy x-ray absorptioometry (DXA) which reported that areal bone mineral density (a BMD ; bone mineral content per projected area) increased with exercise, the studies using peripheral quantitative computed tomography (pQCT) revealed that an improvement in mechanical properties of adult bone in response to exercise is related to negative changes in volumetric BMD (vBMU ; bone mineral content in a unit volume). Furthermore, pQCT studies showed that periosteal area and cortical area were significantly greater in trained bone, together with an increase in cortical thickness. Thus the improvement in the mechanical properties of bone in response to long-term physical exercise is related to geometric adaptation and not vBMD. Due to radiation, pQCT studies were limited to selected slices of bone and whole bone structure of human has not been studied. In the present study, whole bone structure of tibia and calcaneus of athletes was analyzed by MRI. Furthermore, mechanical properties of the bone were simulated in silico.