title: Effects of Russian current and low-frequency pulsed current on discomfort level and current amplitude at 10% maximal knee extensor torque.
abstract: BACKGROUND
  Low-frequency pulsed current (LFPC) and Russian current (RC), a type of kilohertz-frequency alternating current, have been frequently used for muscle strengthening in rehabilitation programs. Despite the popularity of these current types, it is unclear which is most effectively able to generate a similar submaximal torque with minimal discomfort and current amplitude.
  
  
  OBJECTIVE
  To compare discomfort and current amplitude between LFPC and RC to achieve a knee extensor torque of 10% of the maximal isometric voluntary contraction (MIVC).
  
  
  METHODS
  Twenty-two healthy subjects were subjected to three electrically elicited knee extensor submaximal contractions (10% MIVC) that were sustained for 10 seconds. The current amplitude required to achieve 10% MIVC and subjective discomfort were assessed directly by the electrical stimulator and with the Visual Analogue Pain Scale, respectively. A paired t-test was used to determine differences between the electrical currents (α = 0.05).
  
  
  RESULTS
  LFPC required significantly lower current amplitude (15%) and a lower discomfort level (50%) to achieve 10% of MIVC compared to RC.
  
  
  CONCLUSIONS
  LFPC current seems to be more effective than RC with respect to discomfort level and current amplitude to produce 10% of MIVC.
authors.affiliation: Exercise Research Laboratory, School of Physical Education, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Marco Aurélio
authors.initials: MA
authors.lastname: Vaz
authors.forename: Fernando Amâncio
authors.initials: FA
authors.lastname: Aragão
authors.forename: Émerson S
authors.initials: ÉS
authors.lastname: Boschi
authors.forename: Rafael
authors.initials: R
authors.lastname: Fortuna
authors.forename: Mônica de Oliveira
authors.initials: Mde O
authors.lastname: Melo
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004599:Electric Stimulation Therapy / Q000009:adverse effects* / Q000379:methods*; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000502:physiology*; D010146:Pain / Q000175:diagnosis / Q000209:etiology*; D010147:Pain Measurement; D013997:Time Factors; D019415:Torque; D016896:Treatment Outcome; D055815:Young Adult