Limited difference in time to failure between sustained force and position control contractions with the knee extensors
Limited difference in time to failure between sustained force and position control contractions with the knee extensors
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DOI：
10.1111/j.1600-0838.2010.01148.x
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发表时间：
2011-12-01
影响因子：
4.1
通讯作者：
Magnusson, S. P.
中科院分区：
文献类型：
--
作者：
Bojsen-Moller, J.;Schwartz, S.;Magnusson, S. P.
不同类型的收缩疲劳任务(“力/位置任务”)表明，神经肌肉损伤率与任务相关。不同类型的肢体关节的疲劳阻力是否一致尚不清楚，因为力-位置范式主要应用于不稳定条件下的上肢关节。因此，本研究的目的是调查更稳定的膝关节中的任务依赖性。14名受试者进行了两次持续的等长膝关节伸肌收缩直至失败。在力量任务中，20%的最大自主收缩力能在视觉反馈的情况下保持尽可能长的时间，而在位置任务中，负荷相似，但受试者得到的是视角反馈。两组在失败时间(力量任务：423+/-61 S，体位任务：379+/-48 S)、肌电波幅增加或感觉劳累方面差异无统计学意义。力-位置范式以前没有应用于股四头肌，目前和以前的结果之间的差异可能部分归因于关节的稳定性和协同收缩肌肉的体积，因此，除了先前提到的肌肉疲劳机制外，相关关节和肌肉执行器的机械设计可能会影响持续次最大收缩期间的任务依赖性。
Different types of contractile fatiguing tasks ("force/position tasks") have shown that the rate of neuromuscular impairment is task dependent. Whether fatigue resistance is uniform across different types of limb joints is poorly understood because the force-position paradigm has mainly been applied to upper extremity joints under unstable conditions. Therefore, the purpose of the present study was to investigate task dependency in the more stable knee joint. Fourteen subjects performed two sustained isometric knee extensor contractions to failure. In the force task, 20% of maximal voluntary contraction force was maintained for as long as possible with visual feedback of the force, while in the position task, the load was similar, but subjects received visual joint angle feedback. No significant difference was observed in time to failure (force task: 423 +/- 61 s, position task: 379 +/- 48 s), increase in electromyographic amplitude or perceived exertion between tasks. The force-position paradigm has not been applied previously to the quadriceps, and the difference between the present and the previous results may partly be attributed to joint stability and the volume of co-contracting muscles, such that in addition to the previously noted mechanisms of muscle fatigue, the mechanical design of the relevant joint and muscle actuators may influence task dependency during sustained submaximal contractions.