Ankle position and voluntary contraction alter maximal M waves in soleus and tibialis anterior

Frigon, Alain, Carroll, Timothy J., Jones, Kelvin E., Zehr, E. Paul and Collins, David F. (2007) Ankle position and voluntary contraction alter maximal M waves in soleus and tibialis anterior. Muscle & Nerve, 35 6: 756-766.


Author Frigon, Alain
Carroll, Timothy J.
Jones, Kelvin E.
Zehr, E. Paul
Collins, David F.
Title Ankle position and voluntary contraction alter maximal M waves in soleus and tibialis anterior
Journal name Muscle & Nerve   Check publisher's open access policy
ISSN 1097-4598
0148-639X
Publication date 2007-06
Sub-type Article (original research)
DOI 10.1002/mus.20747
Volume 35
Issue 6
Start page 756
End page 766
Total pages 11
Place of publication New York
Publisher Wiley
Language eng
Subject 1109 Neurosciences
Abstract 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 (Mmax) were recorded using surface electrodes from soleus and tibialis anterior (TA) at static positions over the full range of ankle movement at 5° 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 Mmax, Hmax, and the Hmax to Mmax 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 Mmax recorded at similar joint angle and contraction strength. Muscle Nerve, 2007
Formatted abstract 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 (Mmax) were recorded using surface electrodes from soleus and tibialis anterior (TA) at static positions over the full range of ankle movement at 5° 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 Mmax, Hmax, and the Hmax to Mmax 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 Mmax recorded at similar joint angle and contraction strength. Muscle Nerve, 2007
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Human Movement Studies Publications
 
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