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首页> 外文期刊>Medicine and science in sports and exercise >Changes in Running Kinematics, Kinetics, and Spring-Mass Behavior over a 24-h Run.
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Changes in Running Kinematics, Kinetics, and Spring-Mass Behavior over a 24-h Run.

机译：在24小时的跑步过程中跑步运动学，动力学和弹簧质量行为的变化。

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PURPOSE: : This study investigated the changes in running mechanics and spring-mass behavior over a 24-h treadmill run (24TR). METHODS: : Kinematics, kinetics, and spring-mass characteristics of the running step were assessed in 10 experienced ultralong-distance runners before, every 2 h, and after a 24TR using an instrumented treadmill dynamometer. These measurements were performed at 10 km.h, and mechanical parameters were sampled at 1000 Hz for 10 consecutive steps. Contact and aerial times were determined from ground reaction force (GRF) signals and used to compute step frequency. Maximal GRF, loading rate, downward displacement of the center of mass, and leg length change during the support phase were determined and used to compute both vertical and leg stiffness. RESULTS: : Subjects' running pattern and spring-mass behavior significantly changed over the 24TR with a 4.9% higher step frequency on average (because of a significantly 4.5% shorter contact time), a lower maximal GRF (by 4.4% on average), a 13.0% lower leg length change during contact, and an increase in both leg and vertical stiffness (+9.9% and +8.6% on average, respectively). Most of these changes were significant from the early phase of the 24TR (fourth to sixth hour of running) and could be speculated as contributing to an overall limitation of the potentially harmful consequences of such a long-duration run on subjects' musculoskeletal system. CONCLUSIONS: : During a 24TR, the changes in running mechanics and spring-mass behavior show a clear shift toward a higher oscillating frequency and stiffness, along with lower GRF and leg length change (hence a reduced overall eccentric load) during the support phase of running.
机译：目的：：本研究调查了24小时跑步机（24TR）的跑步力学和弹簧质量行为的变化。方法：在24TR之前，每2小时和之后，使用仪器式测功机在10TR有经验的超长跑运动员中评估跑步步骤的运动学，动力学和弹簧质量特性。这些测量以10 km.h的速度进行，并以1000 Hz的频率连续10个步骤对机械参数进行采样。根据地面反作用力（GRF）信号确定接触时间和飞行时间，并将其用于计算步进频率。确定了最大GRF，加载速率，质心向下位移以及支撑阶段的腿长变化，并将其用于计算垂直和腿部刚度。结果：：受试者的跑步方式和弹簧质量行为在24TR上发生了显着变化，平均步进频率提高了4.9％（由于接触时间明显缩短了4.5％），最大GRF降低了（平均降低了4.4％），接触过程中小腿长度变化降低了13.0％，腿部和垂直刚度均增加（分别平均增加9.9％和+ 8.6％）。从24TR的早期阶段（跑步的第四到第六个小时）开始，这些变化中的大多数是显着的，可以推测为这种长期运行对受试者的骨骼肌肉系统的潜在有害后果的总体限制。结论：在24TR期间，在支撑阶段，跑步力学和弹簧质量行为的变化明显向较高的振荡频率和刚度变化，同时GRF和腿长变化较小（因此减小了整体偏心载荷）。运行。

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