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目的比较两种疲劳方案对人体落地动作下肢关节运动学及冲击力时/频域特征的影响。方法选取15名优秀跑、跳类专项男性运动员,利用Vicon运动捕捉系统和Kistler三维测力台比较两种疲劳方案(恒速跑、折返跑+垂直纵跳)前后落地时矢、额状面运动学和地面反作用力(ground reaction force,GRF)时/频域特征。结果(1)两种疲劳方案均会造成髋、膝关节在矢状面上的角度减小、屈曲活动度增加,且采用跑+跳方案时踝关节屈曲活动度、膝关节最大屈曲角速度增加(P<0.05),髋关节外展活动度以及髋、膝关节最大外展角速度增加(P<0.05);(2)两种疲劳方案前后,冲击力时域特征均无显著差异;采用跑和跑+跳方案,分别在3.51、8.20 Hz及1.17、3.51、7.03 Hz下表现出GRF频谱振幅减小(P<0.05)。结论两种疲劳方案均会导致下肢在受到落地冲击时更多采用屈曲着地方式,但跑+跳方案表现更明显且干预时间更短,从实验方法学角度更具优势。研究结果可为研究疲劳后的力特征提供进一步参考。
Objective To compare the effects of two kinds of fatigue programs on the kinematics and impact force / frequency domain characteristics of the lower limbs when landing on the ground. Methods Fifty excellent male runners of running and jumping were selected. The Vicon motion capture system and Kistler three-dimensional force-measuring platform were used to compare the results of two kinds of fatigue programs (constant speed run, turn-back run and vertical run-length jump) Learning and ground reaction force (GRF) time / frequency domain characteristics. Results (1) Both of the two kinds of fatigue programs could reduce the angle of sagittal plane and increase the flexion activity of the hip and knee joint. The flexion mobility of the ankle joint and the maximum flexion angular velocity of knee joint increased (P <0.05), and the maximum abduction angular velocity of hip and knee joint increased (P <0.05). (2) There were no significant differences in the time-domain characteristics of impact before and after the two kinds of fatigue programs. + Hopping scheme, the amplitude of GRF spectrum was decreased (P <0.05) at 3.51, 8.20 Hz and 1.17, 3.51 and 7.03 Hz, respectively. Conclusion Both of the two kinds of fatigue programs will lead to more flexing and landing of lower extremities in the event of ground impact. However, the program of running and jumping is more obvious and the intervention time is shorter, which is more advantageous from the experimental methodological point of view. The results can provide further reference for studying the force characteristics after fatigue.