title: Twitch potentiation induced by two different modalities of neuromuscular electrical stimulation: implications for motor unit recruitment.
abstract: BACKGROUND
  We tested the hypothesis that twitch potentiation would be greater following conventional (CONV) neuromuscular electrical stimulation (50-µs pulse width and 25-Hz frequency) compared with wide-pulse high-frequency (WPHF) neuromuscular electrical stimulation (1-ms, 100-Hz) and voluntary (VOL) contractions, because of specificities in motor unit recruitment (random in CONV vs. random and orderly in WPHF vs. orderly in VOL).
  
  
  METHODS
  A single twitch was evoked by means of tibial nerve stimulation before and 2 s after CONV, WPHF, and VOL conditioning contractions of the plantar flexors (intensity: 10% maximal voluntary contraction; duration: 10 s) in 13 young healthy subjects.
  
  
  RESULTS
  Peak twitch increased (P<0.05) after CONV (+4.5±4.0%) and WPHF (+3.3±5.9%), with no difference between the 2 modalities, whereas no changes were observed after VOL (+0.8±2.6%).
  
  
  CONCLUSIONS
  Our results demonstrate that presumed differences in motor unit recruitment between WPHF and CONV do not seem to influence twitch potentiation results.
authors.affiliation: School of Physical Education and Sport, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Sarah
authors.initials: S
authors.lastname: Regina Dias Da Silva
authors.forename: Daria
authors.initials: D
authors.lastname: Neyroud
authors.forename: Nicola A
authors.initials: NA
authors.lastname: Maffiuletti
authors.forename: Julien
authors.initials: J
authors.lastname: Gondin
authors.forename: Nicolas
authors.initials: N
authors.lastname: Place
mesh_terms: D000328:Adult; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D009469:Neuromuscular Junction / Q000502:physiology*; D011999:Recruitment, Neurophysiological / Q000502:physiology*; D013979:Tibial Nerve / Q000502:physiology*; D055815:Young Adult
keywords: NMES; frequency; plantar flexors; pulse width; twitch potentiation