A noninvasive, log-transform method for fiber type discrimination using mechanomyography

作者：Herda Trent J; Housh Terry J; Fry Andrew C; Weir Joseph P; Schilling Brian K; Ryan Eric D; Cramer Joel T^*

来源：Journal of Electromyography and Kinesiology, 2010, 20(5): 787-794.

DOI：10.1016/j.jelekin.2010.01.004

• EMG
• Electromyography
• MMG
• Motor unit activation strategies

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.

• 出版日期2010-10