【摘要】 研究目的：探究有跌倒史的老年人在不同步速下跨越障碍物时，下肢关节的力矩峰值特征、下肢关节贡献率和代偿机制。研究方法：招募健康老年人和有跌倒史老年人各30名，通过红外高速动作捕捉系统QUALISYS和三维测力台KISTLER，获取老年人在1.05 m/s、1.41 m/s和1.74 m/s三种步速下，跨越高度为其身高15%障碍物时的力学特征数据，之后通过Visual 3D软件进行建模与分析。研究结果：研究结果：随着步速增加，伸膝力矩峰值、踝跖屈力矩峰值以及健康组屈髋力矩双峰值均呈显著性增加（P＜0.05）；与健康组相比，跌倒组的屈髋力矩双峰值均显著小于健康组（P＜0.05）；在中速行走过程中，跌倒组的左侧髋关节贡献率显著高于健康组（P=0.025），而踝关节贡献率则显著低于健康组（P=0.044）；支撑腿和跨越腿触地时刻的前-后方向动态稳度随着步速增加而增加（P=0.007、P=0.002）。研究结论：与健康老年人相比，有跌倒史的老年人力矩峰值、地面反作用力峰值以及前-后方向动态稳度较低；随着步速增加，老年人下肢力学参数和动态稳度显著增加，行走稳定性得到改善；与健康老年人相比，有跌倒史的老年人通常更依赖髋关节的动作贡献，并减少踝关节的参与度。基于这些结果，建议将快速步行锻炼纳入老年人日常防跌倒锻炼计划，并结合髋、膝、踝关节进行协同训练。

【Abstract】 Objective To explore the peak moment characteristics of lower limb joints, as well as the contribution rate and compensation mechanism of lower limb joints when elderly people with a history of falls cross obstacles at different paces. Methods The study recruited 30 healthy older adults and 30 elderly fallers. The infrared high-speed motion capture system QUALISYS and the three-dimensional force platform KISTLER were used to obtain the mechanical characteristic data of the elderly when they crossed an obstacle with a height of 15% of their height at three walking speeds of 1.05 m/s, 1.41 m/s, and 1.74 m/s. The data were then modeled and analyzed using Visual 3D software. Results As walking speed increased, the peak knee extension moment, peak ankle plantar flexion moment, and double peak value of hip flexion moment in the healthy group all increased significantly (P<0.05). Compared with the healthy group, the double peak values of hip flexion moment in the fall group were significantly smaller than those in the healthy group (P<0.05). During moderate walking, the contribution rate of the left hip joint in the fall group was significantly higher than that of the healthy group (P=0.025)，while the contribution rate of the ankle joint was significantly lower (P=0.044) .The margin of stability in the front-to-back direction at the moment of ground contact of the stance leg and the stride leg increased with walking speed (P=0.007,P=0.002). Conclusions Compared with healthy elderly individuals, the elderly fallers have lower peak torque, peak ground reaction force, and dynamic stability in the front-to-back direction. As the walking speed increases, the mechanical parameters and the margin of stability increase significantly, and walking stability is improved. Compared with healthy elderly people, elderly fallers usually rely more on the contribution of hip joint movements and reduce the involvement of ankle joints. Based on these results, it is recommended to incorporate fast walking exercises into the daily fall prevention exercise program for the elderly and combine them with coordinated training of the hip, knee, and ankle joints.