title: Blood flow response to electrically induced twitch and tetanic lower-limb muscle contractions.
abstract: OBJECTIVE
  To compare the effect of electric stimulation (ES)-induced twitch with tetanic leg muscle contractions on blood flow responses and to assess blood flow responses in the contralateral inactive leg.
  
  
  METHODS
  Intervention with within-subject comparisons.
  
  
  METHODS
  University research laboratory.
  
  
  METHODS
  A volunteer sample of 12 healthy men (mean age, 25.1+/-3.0y).
  
  
  METHODS
  ES was applied at 1 and 3Hz to induce twitch contractions and at 35Hz to induce tetanic contractions of the lower- and upper-leg muscles. Exercise periods consisted of ES/rest cycles (6s/20s) for 5 minutes.
  
  
  METHODS
  Blood flow velocity changes measured by echo Doppler ultrasonography at rest and during the first 2 subsequent ES cycles.
  
  
  RESULTS
  Blood flow significantly increased from resting values for the tetanic 2-leg, tetanic 1-leg, and 3-Hz conditions, but not for the 1-Hz twitch condition or in the inactive leg.
  
  
  CONCLUSIONS
  Both tetanic and 3-Hz twitch contractions, but not 1-Hz twitch contractions, increased leg blood flow in humans. Because blood flow elevations induced by the 3-Hz contractions did not differ statistically from those induced by the tetanic contractions but were realized with less discomfort, this mode is preferable for therapeutic interventions. Because stimulation of the ipsilateral leg muscles did not change blood flow in the contralateral inactive leg, the muscles in the area of desired effect must be stimulated.
authors.affiliation: Vrije Uniersiteit, Faculty of Human Movement Science and Institute for Fundamental and Clinical Human Movement Sciences, Amsterdam, The Netherlands. t.janssen@fbw.vu.nl
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Janssen
authors.forename: Maria T
authors.initials: MT
authors.lastname: Hopman
mesh_terms: D000704:Analysis of Variance; D001783:Blood Flow Velocity / Q000502:physiology*; D002985:Clinical Protocols / Q000592:standards; D004558:Electric Stimulation / Q000379:methods*; D005081:Exercise Therapy / Q000379:methods; D005263:Femoral Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction; D007866:Leg / Q000098:blood supply* / Q000000981:diagnostic imaging; D016014:Linear Models; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D009126:Muscle Relaxation / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply*; D010101:Oxygen Consumption; D012039:Regional Blood Flow; D012146:Rest; D018608:Ultrasonography, Doppler