Physical activity (PA) enhances proximal femur bone mass, as assessed using projectional imaging techniques. However, these techniques average data over large volumes, obscuring spatially heterogeneous adaptations. The current study used quantitative computed tomography, statistical parameter mapping, and subject-specific finite element (FE) modeling to explore spatial adaptation of the proximal femur to PA. In particular, we were interested in adaptation occurring at the superior femoral neck and improving strength under loading from a fall onto the greater trochanter. High/long jump athletes (n = 16) and baseball pitchers (n = 16) were utilized as within-subject controlled models as they preferentially load their take-off leg and leg contralateral to their throwing arm, respectively. Controls (n = 15) were included but did not show any dominant-to-nondominant (D-to-ND) leg differences. Jumping athletes showed some D-to-ND leg differences but less than pitchers. Pitchers had 5.8% (95% confidence interval [CI] 3.9%-7.6%) D-to-ND leg differences in total hip volumetric bone mineral density (vBMD), with increased vBMD in the cortical compartment of the femoral neck and trochanteric cortical and trabecular compartments. Voxel-based morphometry analyses and cortical bone mapping showed pitchers had D-to-ND leg differences within the regions of the primary compressive trabeculae, inferior femoral neck, and greater trochanter but not the superior femoral neck. FE modeling revealed pitchers had 4.1% (95% CI 1.4%-6.7%) D-to-ND leg differences in ultimate strength under single-leg stance loading but no differences in ultimate strength to a fall onto the greater trochanter. These data indicate the asymmetrical loading associated with baseball pitching induces proximal femur adaptation in regions associated with weight bearing and muscle contractile forces and increases strength under single-leg stance loading. However, there were no benefits evident at the superior femoral neck and no measurable improvement in ultimate strength to common injurious loading during aging (ie, fall onto the greater trochanter), raising questions as to how to better target these variables with PA. © 2019 American Society for Bone and Mineral Research.

中文翻译：

---

近端股骨对身体活动的异质空间和强度适应：受试者内控制的横截面研究。

根据投影成像技术的评估，体力活动 (PA) 可增强股骨近端骨量。然而，这些技术对大量数据进行平均，从而掩盖了空间异构适应。当前的研究使用定量计算机断层扫描、统计参数映射和特定主题的有限元 (FE) 建模来探索股骨近端对 PA 的空间适应性。特别是，我们对股骨颈上发生的适应以及在跌倒到大转子上的负载下提高强度感兴趣。跳高/跳远运动员（n = 16）和棒球投手（n = 16）被用作受试者内控制模型，因为他们分别优先加载起跳腿和投掷臂对侧的腿。纳入对照 (n = 15)，但未显示任何显性腿与非显性腿 (D-to-ND) 差异。跳跃运动员表现出一些 D 到 ND 腿部差异，但小于投手。投手的 D 腿与 ND 腿的总髋关节体积骨矿物质密度 (vBMD) 存在 5.8%（95% 置信区间 [CI] 3.9%-7.6%）差异，股骨颈皮质室和转子皮质的 vBMD 增加和小梁室。基于体素的形态测量分析和皮质骨测绘显示，捕虫笼在初级压缩小梁、下股骨颈和大转子区域内具有 D 到 ND 腿部差异，但在上股骨颈区域内没有差异。FE 模型显示，投手在单腿站立负载下，D 腿与 ND 腿的极限力量存在 4.1% (95% CI 1.4%-6.7%) 差异，但跌倒到大转子上的极限力量没有差异。这些数据表明，与棒球投球相关的不对称负载会引起与承重和肌肉收缩力相关的区域的近端股骨适应，并增加单腿站立负载下的力量。然而，上股骨颈没有明显的好处，并且对于衰老过程中常见的损伤性负荷（即落在大转子上）的极限强度没有可测量的改善，这引发了如何更好地利用 PA 来瞄准这些变量的问题。© 2019 美国骨与矿物质研究学会。