title: Muscle velocity recovery cycles: Comparison between surface and needle recordings.
abstract: BACKGROUND
  Recording of muscle velocity recovery cycles (MVRCs) has been developed as a technique to investigate the pathophysiology of muscle diseases. MVRCs have been measured by direct muscle stimulation and concentric electromyographic needle recording. This study was undertaken to determine whether recordings can be made with surface electrodes.
  
  
  METHODS
  MVRCs with 1 and 2 conditioning stimuli were recorded simultaneously with concentric needle and surface electrodes from the brachioradialis muscle in 12 healthy volunteers. Muscle relative refractory period, early and late supernormality, and extra-late supernormality were compared between the recording techniques.
  
  
  RESULTS
  Surface recordings were possible in all subjects. The multifiber action potentials recorded with surface electrodes were smaller than those recorded with needles, but there was no significant difference between any of their MVRC properties.
  
  
  CONCLUSIONS
  MVRCs can be recorded with surface electrodes in healthy subjects. The use of surface electrodes may facilitate the technique of recording MVRCs.
authors.affiliation: Department of Neurosurgery, Inselspital, Bern University Hospital and University of Bern, Freiburgstrasse 10, 3010 Bern, Switzerland.
authors.forename: Werner J
authors.initials: WJ
authors.lastname: Z'graggen
authors.affiliation: Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.
authors.forename: Joël P
authors.initials: JP
authors.lastname: Trautmann
authors.affiliation: Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.
authors.forename: Delphine
authors.initials: D
authors.lastname: Boërio
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK.
authors.forename: Hugh
authors.initials: H
authors.lastname: Bostock
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D004558:Electric Stimulation; D004566:Electrodes; D004576:Electromyography / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D009339:Needles; D011930:Reaction Time / Q000502:physiology; D055815:Young Adult
keywords: characterization of muscle disease; excitability measurements; membrane potential; muscle; myopathy; surface EMG