title: Differences in the recruitment curves obtained with monopolar and bipolar electrode configurations in the quadriceps femoris.
abstract: We sought to verify whether the stimulation intensity at which M-wave amplitude reaches a plateau actually corresponds to full motor unit activation in monopolar and bipolar configurations.
  
  
  
  M-waves and twitches were evoked using femoral nerve stimulation of gradually increasing intensity in 21 subjects. Recruitment curves corresponding to the amplitude of the first phase (AmpliFIRST ) and peak-to-peak amplitude (AmpliPP ) of the M-wave were obtained in the vastus lateralis, vastus medialis, and rectus femoris in monopolar and bipolar configurations.
  
  
  
  In all muscles, bipolar M-waves and twitches reached plateau at a significantly lower stimulus intensity compared with monopolar M-waves (P < 0.05). The different behavior of monopolar and bipolar M-waves with stimulus intensity was found for both AmpliFIRST and AmpliPP .
  
  
  
  In a bipolar configuration, the stimulus intensity at which M-waves plateau should be increased by at least 10%-20% to achieve complete motor unit recruitment. Muscle Nerve 54: 118-131, 2016.
authors.affiliation: Department of Electrical and Electronical Engineering, Public University of Navarra, Campus de Arrosadía, s/n., 31006, Pamplona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Rodriguez-Falces
authors.affiliation: Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Place
mesh_terms: D000328:Adult; D004558:Electric Stimulation; D004566:Electrodes / Q000145:classification; D004576:Electromyography; D005267:Femoral Nerve / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D007717:Knee / Q000294:innervation; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D052097:Quadriceps Muscle / Q000502:physiology*; D011999:Recruitment, Neurophysiological / Q000502:physiology*; D018709:Statistics, Nonparametric; D055815:Young Adult
keywords: bipolar recording; femoral nerve stimulation; monopolar recording; motor unit recruitment; plateau stimulus intensity; recruitment curve