Neuromechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS, USA.
Physiol Meas. 2013 Oct;34(10):1293-301. doi: 10.1088/0967-3334/34/10/1293. Epub 2013 Sep 11.
The purpose of the present study was to examine possible correlations between the b terms (slopes) form the log-transformed mechanomyographic amplitude (MMGRMS)-force relationships and the fatigue index calculated from 50 maximal concentric contractions. Forty healthy subjects (age = 21 ± 2 yr) performed isometric ramp contractions from 5% to 85% of their maximal voluntary contraction followed by a 50-repetition concentric fatigue protocol of the leg extensors, fatigue index (%) was calculated from the 50-repetitions. MMG was recorded during the ramp contractions from the vastus lateralis (VL) and rectus femoris (RF). The b terms (slopes) were calculated from the log-transformed MMGRMS-force relationships. Correlations were performed comparing the b terms from the MMGRMS-force relationships for the VL and RF with the fatigue index. Significant positive correlations were found among the b terms from the MMGRMS-force relationships for the VL (p = 0.007, r = 0.417) and RF (p = 0.014, r = 0.386) with the fatigue index. The b terms from the log-transformed MMGRMS-force relationships for the VL and RF may have reflected muscle fiber type composition and, thus, correlated with the fatigue index. This adds further support that the MMGRMS-force relationships may reflect muscle fiber type composition.
本研究旨在探讨经对数转换后的肌动描记图幅度（MMGRMS）-力量关系的 b 项（斜率）与 50 次最大向心收缩计算得出的疲劳指数之间可能存在的相关性。40 名健康受试者（年龄=21±2 岁）进行等长斜坡收缩，从 5%到 85%的最大自主收缩，随后进行 50 次重复的腿伸肌向心疲劳协议，疲劳指数（%）是从 50 次重复中计算得出的。在斜坡收缩期间，从股外侧肌（VL）和股直肌（RF）记录肌电图。从对数转换后的 MMGRMS-力量关系中计算 b 项（斜率）。对 VL 和 RF 的 MMGRMS-力量关系的 b 项与疲劳指数进行了相关性比较。VL（p=0.007，r=0.417）和 RF（p=0.014，r=0.386）的 MMGRMS-力量关系的 b 项与疲劳指数之间存在显著正相关。VL 和 RF 的对数转换后的 MMGRMS-力量关系的 b 项可能反映了肌肉纤维类型组成，因此与疲劳指数相关。这进一步支持了 MMGRMS-力量关系可能反映肌肉纤维类型组成的观点。
