期刊
MUSCLE & NERVE
卷 35, 期 6, 页码 756-766出版社
JOHN WILEY & SONS INC
DOI: 10.1002/mus.20747
关键词
compound muscle action potential; contraction level; muscle length; M-wave; reflex
资金
- Canadian Institutes of Health Research [64450] Funding Source: Medline
Compound muscle action potentials (CMAPs) recorded using surface electrodes are often used to assess the excitability of neural pathways to skeletal muscle. However, the amplitude of CMAPs can be influenced by changes at the recording site, independent of mechanisms within the central nervous system. We quantified how joint angle and background contraction influenced CMAP amplitude. In seven subjects CMAPs evoked by supramaximal transcutaneous electrical stimulation of motor axons (M-max) were recorded using surface electrodes from soleus and tibialis anterior (TA) at static positions over the full range of ankle movement at 5 degrees intervals. Across subjects the peak-to-peak amplitude of Mmax was 155% and 159% larger at the shortest than longest muscle lengths for soleus and TA, respectively. In five subjects the effect of ankle position and voluntary contraction on M-wave/H-reflex recruitment curves was assessed in the soleus. Both ankle position and level of contraction significantly influenced M-max, H-max, and the H-max to M-max ratio, but there were no interactions between the two parameters. These peripheral changes that influence Mmax will also impact other CMAPs such as submaximal M-waves, H-reflexes, and responses to transcranial magnetic stimulation. As such, during experimental studies CMAPs evoked at a given joint angle and contraction level should be normalized to M-max recorded at similar joint angle and contraction strength.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据