A noninvasive, log-transform method for fiber type discrimination using mechanomyography
A noninvasive, log-transform method for fiber type discrimination using mechanomyography
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DOI：
10.1016/j.jelekin.2010.01.004
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发表时间：
2010-10-01
影响因子：
2.5
通讯作者：
Cramer, Joel T.
中科院分区：
文献类型：
--
作者：
Herda, Trent J.;Housh, Terry J.;Cramer, Joel T.
本研究检测了有氧训练（AT）、阻力训练（RT）和久坐（SED）个体的对数转换肌力图（MMGRMS）和肌电图（EMGRMS）振幅与力的关系。受试者进行从5%到90%最大自愿收缩的等距斜面收缩。取肌肉活检，记录股外侧肌的大腿皮褶、肌电图和肌电图。线性回归模型拟合对数变换后的EMGRMS和MMGRMS与力的关系。计算斜率（b系数）和y截距的反对数（a系数）。AT组I型纤维面积百分比最高，RT组IIa型纤维面积百分比最高，SED组IIx型纤维面积百分比最高。在MMGRMS和EMGRMS与力的关系中，AT组的a系数高于RT组和SED组，而在MMGRMS与力的关系中，AT组的b系数低于RT组和SED组。a系数之间的组间差异可能反映了皮下脂肪作为过滤器的作用，从而降低了EMGRMS和MMGRMS。在MMGRMS模式中，AT组较低的b系数可能反映了运动单元激活策略中纤维面积相关的差异。Elsevier Ltd.出版。
This study examined the log-transformed mechanomyographic (MMGRMS) and electromyographic (EMGRMS) amplitude vs. force relationships for aerobically-trained (AT), resistance-trained (RT), and sedentary (SED) individuals. Subjects performed isometric ramp contractions from 5% to 90% maximal voluntary contraction. Muscle biopsies were collected and thigh skinfolds, MMG and EMG were recorded from the vastus lateralis muscle. Linear regression models were fit to the log-transformed EMGRMS and MMGRMS vs. force relationships. The slope (b coefficient) and the antilog of the y-intercept (a coefficient) were calculated. The AT group had the highest percentage of type I fiber area, the RT group had the highest percentage of type IIa fiber area, and the SED group had the highest percentage of type IIx fiber area. The a coefficients were higher for the AT group than the RT and SED groups in both the MMGRMS and EMGRMS vs. force relationships, whereas the b coefficients were lower for the AT group than the RT and SED groups only in the MMGRMS vs. force relationship. The group differences among the a coefficients may have reflected subcutaneous fat acting as a filter thereby reducing EMGRMS and MMGRMS. The lower b coefficients for the AT group in the MMGRMS patterns may have reflected fiber area-related differences in motor unit activation strategies. Published by Elsevier Ltd.