Effect of combined variation of force amplitude and rate of force development on the modulation characteristics of muscle activation during rapid isometric aiming force production.
Effect of combined variation of force amplitude and rate of force development on the modulation characteristics of muscle activation during rapid isometric aiming force production.
复制标题
力幅和力发展速率的组合变化对快速等长瞄准力产生期间肌肉激活的调制特性的影响。
DOI：
10.1007/s00221-005-0099-6
复制
发表时间：
2006
影响因子：
2
通讯作者：
Stelmach,GeorgeE
中科院分区：
文献类型：
--
作者：
Park,Jin-Hoon;Stelmach,GeorgeE
针对快速目标定向肢体运动的研究表明，可以通过肌肉活动的调制模式来定义各种控制方案。本研究的目的是解决的问题，在何种程度上同时控制力的幅度，和力的发展速度的影响与产生快速等长瞄准力在手肘关节肌肉激活的调制特性。受试者被指示在系统变化的力率条件下产生快速等长力脉冲，以三种不同的力振幅（其最大自主收缩的15%、35%和55%），力率范围从快速准确的力率到可能的最快力率。结果表明，通过增加力发展速率（dF/dt）可获得更大的力振幅，而达到峰值力的时间保持相对恒定。在所有力率条件下，肌电（EMG）爆发的幅度作为力振幅的函数系统地增加。主要的发现是，与不同的力幅值相关的EMG爆发持续时间的特征在力率条件之间显示出显着差异。在快速而准确的力-速率条件下，激动剂爆发的持续时间与力的振幅呈线性增加。然后在其余三个力率要求中观察到激动剂爆发逐渐过渡到固定持续时间。随着越来越快的力率，在三个力振幅的激动剂爆发持续时间没有变化。这些结果表明，在力的振幅和力率检查相对于最快的力率的组合变化的影响控制模式的肌肉激活过程中的快速等长力的生产。所观察到的EMG调制模式的变化可能是由于肌肉收缩特性所施加的约束。
Studies of rapid target-directed limb movements have suggested that various control schemes can be defined by the modulation pattern of the muscle activity. The present study was aimed to address the question regarding the extent to which a simultaneous control of force amplitude, and rate of force development influences the modulation characteristics of muscle activation associated with producing rapid isometric aiming forces at the elbow joint. The subjects were instructed to produce rapid isometric force pulses to three different force amplitudes (15, 35, and 55% of their maximal voluntary contractions) under systematically varied force-rate conditions ranging from a fast and accurate force-rate to the fastest force-rate possible. The results showed that larger force amplitudes were achieved by increasing the rate of force development (dF/dt) while the time to peak force remained relatively constant. The magnitude of the electromyographic (EMG) burst systematically increased as a function of force amplitude at all force-rate conditions. The primary finding was that the characteristic of the EMG burst duration associated with different force amplitudes showed a significant difference among force-rate conditions. Under a fast and accurate force-rate condition, the duration of the agonist burst increased linearly with force amplitude. A gradual transition into a fixed duration of the agonist burst then was observed over the remaining three force-rate requirements. With increasingly faster force-rates, there were no changes in the agonist burst duration over three force amplitudes. These results indicate that the combined variations in force amplitude and force-rate examined relative to the most rapid force-rate influence the control patterns for the muscle activation during the fast isometric force production. Changes in the EMG modulation patterns observed are likely due to the constraints imposed by muscle contractile properties.