Giddings V L, Beaupré G S, Whalen R T, Carter D R
Mechanical Engineering Department, Stanford University, CA, USA.
Med Sci Sports Exerc. 2000 Mar;32(3):627-34. doi: 10.1097/00005768-200003000-00012.
This study of the foot uses experimentally measured kinematic and kinetic data with a numerical model to evaluate in vivo calcaneal stresses during walking and running.
External ground reaction forces (GRF) and kinematic data were measured during walking and running using cineradiography and force plate measurements. A contact-coupled finite element model of the foot was developed to assess the forces acting on the calcaneus during gait.
We found that the calculated force-time profiles of the joint contact, ligament, and Achilles tendon forces varied with the time-history curve of the moment about the ankle joint. The model predicted peak talocalcaneal and calcaneocuboid joint loads of 5.4 and 4.2 body weights (BW) during walking and 11.1 and 7.9 BW during running. The maximum predicted Achilles tendon forces were 3.9 and 7.7 BW for walking and running.
Large magnitude forces and calcaneal stresses are generated late in the stance phase, with maximum loads occurring at approximately 70% of the stance phase during walking and at approximately 60% of the stance phase during running, for the gait velocities analyzed. The trajectories of the principal stresses, during both walking and running, corresponded to each other and qualitatively to the calcaneal trabecular architecture.
本足部研究利用实验测量的运动学和动力学数据以及数值模型，评估步行和跑步过程中跟骨的体内应力。
在步行和跑步过程中，使用X线电影摄影术和测力板测量来获取外部地面反作用力（GRF）和运动学数据。开发了足部的接触耦合有限元模型，以评估步态期间作用于跟骨的力。
我们发现，计算得出的关节接触力、韧带力和跟腱力的力-时间曲线随踝关节力矩的时间历程曲线而变化。该模型预测，步行时距下关节和跟骰关节的峰值负荷分别为5.4倍体重（BW）和4.2倍体重，跑步时分别为11.1倍体重和7.9倍体重。步行和跑步时预测的跟腱最大力分别为3.9倍体重和7.7倍体重。
在站立阶段后期会产生较大的力和跟骨应力，对于所分析的步态速度，最大负荷出现在步行站立阶段约70%时以及跑步站立阶段约60%时。步行和跑步过程中主应力的轨迹相互对应，并且在质量上与跟骨小梁结构相对应。
