目的：预测皮质骨组织失效应变，探究不同速度跑步对大鼠股骨皮质骨力学性能的影响。 方法：设定皮质骨材料失效应变阈值，针对大鼠股骨有限元模型进行三点弯曲下的断裂模拟，将每次预测所得载荷-位移曲线与同一样本实验曲线进行比较拟合，以此反演预测组织失效应变。 结果：皮质骨组织失效应变在不同速度跑步下存在显著差异，说明不同速度跑步力学刺激对皮质骨结构微观力学性能产生了一定影响，其中组织失效应变在以12 m/min速度跑步中最大，以在20 m/min速度跑步中最小。 结论：以不同速度跑步对皮质骨结构微观力学性能的影响不同。通过观测组织失效应变变化趋势，并结合皮质骨结构的宏观断裂载荷与纳观组织弹性模量变化趋势，探讨不同速度跑步力学刺激对皮质骨结构力学性能的综合影响，并找到有利于提升皮质骨力学性能的跑步速度，为通过跑步锻炼提高骨强度提供理论依据。
Purpose: this study aimed to predict the tissue-level failure strain of cortical bone, and then discussed the effects of different running speeds on the mechanical properties of the rat femoral cortical bone. Methods: three-point bending simulation was carried out on the rat femoral finite element model, and different critical failure strains of cortical bone material were assigned to perform the fracture analysis. The load–displacement curves predicted in each simulation were compared with the experimental data to back-calculate the tissue-level failure strain. Results: the tissue-level failure strains of cortical bone structures under different running speeds were statistically different from each other, which indicated that different mechanical stimuli of running had significant influences on the micromechanical properties. At a running speed of 12 m/min, the cortical bone structure expressed the greatest tissue-level failure strain, and at a running speed of 12 m/min, the cortical bone structure expressed the lowest tissue-level failure strain. Conclusions: The effects of different running speeds on the micromechanical properties of cortical bone were different. Based on the changing trends in the tissue-level failure strain, the effects of running speeds on the mechanical properties of cortical bone structures were discussed in combination with the changes in the failure load and tissue elastic modulus. Finally, the appropriate running speed for improving the mechanical properties of cortical bone was explored, which provided the theoretical basis for improving bone strength through running exercise.