等长斜坡运动与等长阶梯式肌肉动作期间的肌动图幅度和平均功率频率反应。
Mechanomyographic amplitude and mean power frequency responses during isometric ramp vs. step muscle actions.
作者信息
Ryan Eric D, Beck Travis W, Herda Trent J, Hartman Michael J, Stout Jeffrey R, Housh Terry J, Cramer Joel T
机构信息
Department of Health and Exercise Science, Biophysics Laboratory, University of Oklahoma, Norman, OK 73019, USA.
出版信息
J Neurosci Methods. 2008 Mar 15;168(2):293-305. doi: 10.1016/j.jneumeth.2007.10.010. Epub 2007 Oct 24.
The purpose of the present study was to compare the mechanomyographic amplitude (MMG(RMS)) and mean power frequency (MMG(MPF)) vs. torque relationships during isometric ramp and step muscle actions for the vastus lateralis (VL) and rectus femoris (RF) muscles. Nineteen subjects (mean+/-S.D. age=24+/-4 years) performed 2 isometric maximal voluntary contractions (MVCs) before and after 2 or 3 isometric ramp muscle actions from (5-95% MVC) to 9 submaximal step muscle actions (15, 25, 35, 45, 55, 65, 75, 85, and 95% MVC). MMG signals were recorded from the VL and RF muscles, and MMG(RMS) and MMG(MPF) values were computed for each corresponding percentage of the MVC. Absolute and normalized MMG(RMS) and MMG(MPF) vs. torque relationships were analyzed and interpreted on a subject-by-subject and composite pattern basis using polynomial regression and repeated measures ANOVAs. For MMG(RMS) and MMG(MPF), only 16-53% and 11-26% of the individual responses were consistent with the composite polynomial models, respectively. In addition, the normalized composite MMG(RMS) values were greater for the RF than the VL from 35 to 85% MVC. Only 47% of the MMG(RMS) and 5% of the MMG(MPF) individual patterns of responses were the same for the ramp and step muscle actions, and differences were also observed for the composite MMG(RMS) and MMG(MPF) patterns between the ramp and step muscle actions. Overall, these findings indicated that the torque-related patterns of responses for MMG(RMS) and MMG(MPF) were different among subjects (i.e., inter-individual variability) and were muscle- (VL vs. RF) and mode-specific (ramp vs. step).
本研究的目的是比较股外侧肌（VL）和股直肌（RF）在等长斜坡和阶梯式肌肉动作过程中肌机械图幅度（MMG（RMS））和平均功率频率（MMG（MPF））与扭矩的关系。19名受试者（平均±标准差年龄 = 24±4岁）在进行2次或3次从5%至95%最大自主收缩（MVC）的等长斜坡肌肉动作以及9次次最大阶梯式肌肉动作（15%、25%、35%、45%、55%、65%、75%、85%和95%MVC）之前和之后进行了2次等长最大自主收缩（MVC）。从VL和RF肌肉记录MMG信号，并针对MVC的每个相应百分比计算MMG（RMS）和MMG（MPF）值。使用多项式回归和重复测量方差分析，在个体和综合模式基础上分析和解释绝对和归一化的MMG（RMS）以及MMG（MPF）与扭矩的关系。对于MMG（RMS）和MMG（MPF），分别只有16%至53%和11%至26%的个体反应与综合多项式模型一致。此外，在35%至85%MVC范围内，RF的归一化综合MMG（RMS）值大于VL。对于斜坡和阶梯式肌肉动作，只有47%的MMG（RMS）个体反应模式和5%的MMG（MPF）个体反应模式相同，并且在斜坡和阶梯式肌肉动作之间的综合MMG（RMS）和MMG（MPF）模式中也观察到差异。总体而言，这些发现表明，MMG（RMS）和MMG（MPF）与扭矩相关的反应模式在受试者之间存在差异（即个体间变异性），并且具有肌肉特异性（VL与RF）和模式特异性（斜坡与阶梯）。
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