Abstract：
Previous data suggest a correlation between the cross-sectional area of Type II muscle fibers and the degree of non-linearity of the EMG amplitude-force relationship (AFR). In this study we investigated whether the AFR of back muscles could be altered systematically by using different training modalities. We investigated 38 healthy male subjects (aged 19-31 years) who regularly performed either strength or endurance training (ST and ET, n = 13 each) or were physically inactive (controls (C), n = 12). Graded submaximal forces on the back were applied by defined forward tilts in a full-body training device. Surface EMG was measured utilizing a monopolar 4 × 4 quadratic electrode scheme in the lower back area. The polynomial AFR slopes were determined. Between-group tests revealed significant differences for ET vs. ST and C vs. ST comparisons at the medial and caudal electrode positions, but not for ET vs. C. Further, systematic main effects of the \"electrode position\" could be proven for ET and C groups with decreasing x2 coefficients from cranial to caudal and lateral to medial. For ST, there was no systematic main effect of the \"electrode position\". The results point towards training-related changes to the fiber-type composition of muscles in the strength-trained participants, particularly for their paravertebral region.
摘要：
先前的数据表明II型肌纤维的横截面积与EMG振幅-力关系（AFR）的非线性程度之间存在相关性。在这项研究中，我们调查了是否可以通过使用不同的训练方式系统地改变背部肌肉的AFR。我们调查了38名健康男性受试者（19-31岁），他们定期进行力量或耐力训练（ST和ET，每个n=13)或身体不活动(对照(C)，n=12)。通过在全身训练装置中定义的向前倾斜来施加背部的分级次最大力。在下背部区域中使用单极4×4二次电极方案测量表面EMG。确定多项式AFR斜率。组间检验显示ET与ET之间存在显着差异ST和Cvs.内侧和尾部电极位置的ST段比较,但不是ETvs.C.进一步,对于ET和C组，可以证明“电极位置”的系统主要作用，从颅骨到尾部以及从外侧到内侧的x2系数降低。对于ST，“电极位置”没有系统的主要影响。结果表明，在力量训练的参与者中，肌肉的纤维型成分发生了与训练相关的变化，特别是他们的椎旁区域。
