Aagaard P, Simonsen E B, Andersen J L, Magnusson S P, Halkjaer-Kristensen J, Dyhre-Poulsen P
Department of Neurophysiology, Institute of Medical Physiology, Panum Institute, Copenhagen, Denmark.
J Appl Physiol (1985). 2000 Dec;89(6):2249-57. doi: 10.1152/jappl.2000.89.6.2249.
Despite full voluntary effort, neuromuscular activation of the quadriceps femoris muscle appears inhibited during slow concentric and eccentric contractions. Our aim was to compare neuromuscular activation during maximal voluntary concentric and eccentric quadriceps contractions, hypothesizing that inhibition of neuromuscular activation diminishes with resistance training. In 15 men, pretraining electromyographic activity of the quadriceps muscles [vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF)] was 17-36% lower during slow and fast (30 and 240 degrees/s) eccentric and slow concentric contractions compared with fast concentric contractions. After 14 wk of heavy resistance training, neuromuscular inhibition was reduced for VL and VM and was completely removed for RF. Concurrently, electromyographic activity increased 21-52, 22-29, and 16-32% for VL, VM, and RF, respectively. In addition, median power frequency decreased for VL and RF. Eccentric quadriceps strength increased 15-17%, whereas slow and fast concentric strength increased 15 and 8%, respectively. Pre- and posttraining median power frequency did not differ between eccentric and concentric contractions. In conclusion, quadriceps motoneuron activation was lower during maximal voluntary eccentric and slow concentric contractions compared with during fast concentric contraction in untrained subjects, and, after heavy resistance training, this inhibition in neuromuscular activation was reduced.
尽管进行了充分的自主努力，但在缓慢的向心和离心收缩过程中，股四头肌的神经肌肉激活似乎受到抑制。我们的目的是比较股四头肌最大自主向心和离心收缩期间的神经肌肉激活情况，假设神经肌肉激活的抑制会随着阻力训练而减弱。在15名男性中，与快速向心收缩相比，股四头肌（股内侧肌（VM）、股外侧肌（VL）和股直肌（RF））在缓慢和快速（30和240度/秒）离心以及缓慢向心收缩期间的训练前肌电图活动降低了17%-36%。经过14周的高强度阻力训练后，VL和VM的神经肌肉抑制减少，RF的神经肌肉抑制完全消除。同时，VL、VM和RF的肌电图活动分别增加了21%-52%、22%-29%和16%-32%。此外，VL和RF的中位功率频率降低。离心股四头肌力量增加了15%-17%，而缓慢和快速向心力量分别增加了15%和8%。训练前和训练后，离心和向心收缩之间的中位功率频率没有差异。总之，在未训练的受试者中，与快速向心收缩相比，最大自主离心和缓慢向心收缩期间股四头肌运动神经元的激活较低，并且在高强度阻力训练后，这种神经肌肉激活的抑制作用减弱。
