Electrical Stimulation With Different Currents: the Effects on Force, Tolerance and Fatigue in Healthy Subjects
Condition: Healthy
MeSH terms: Fatigue
Study type: Interventional

Summary: 
      Muscle strength is the amount of force generated by muscle contraction. It could be measured
      with an isometric dynamometer. This is a validated tool that could be used to measure Maximal
      Voluntary Isometric Contraction (MVIC) and Maximal Electrical Induced Contraction (MEIC). It
      is claimed that higher MEIC values will result in more force gained.

      If a current is more tolerated it will be easier to achieve better MEIC values. Tolerance to
      an electrical stimulation could be measured with the Visual Analogue Scale (VAS). A ratio
      between Normalized MEIC / VAS is often used, implying that the current is better with a
      higher ratio.

      Muscle fatigue is defined as a temporary loss or decrease in force-generating ability due to
      previous contractions. It is claimed that medium frequency neuromuscular electrical
      stimulation (NMES) generates more fatigue than low frequency currents.

      Aussie is a medium-frequency alternating current, sinusoidal waveform, 1 KHz carrier
      frequency.

      Neo-Russian is a medium-frequency current, rectangular biphasic symmetrical waveform, 2,5 KHz
      carrier frequency.

      Rectangular Biphasic symmetrical (RBS) waveform is a type of Low Pulsed Current (LPC),
      claimed to be better than classical Russian Current.

      Purpose:

      As it has been claimed that LPC is better in MEIC and tolerance, the aim of this study is to
      compare it with two newer medium frequency currents in terms of MEIC, tolerance and fatigue.

      Methods:

      Thirty male subjects, right leg dominant, will receive randomly the 3 types of electrical
      stimulation. Before that, the MVIC will be measured for data normalization.

      The MVIC and MEIC will be measured with an isometric dynamometer. In both measurements,
      subjects will be asked to perform three reps (5 sec work x 120 sec rest) and the best one
      will be used. Whenever the third one was the best, additional measurements will be taken
      until a decrease in torque will be obtained to determine the maximum.

      To apply Aussie electrical stimulation, an Aussie Sport (Ibramed) will be used. To apply
      Neo-Russian, a Neurodyn III (Ibramed) will be used. To apply RBS, a Genesy (Globus) will be
      used.

      The VAS will be used to assess tolerance to each treatment. One week later, the subjects will
      receive, randomly, a fatigue protocol that consists in 21 reps (5 sec work x 5 sec rest) of
      electrical stimulation with the three types of current. The data will be normalized with the
      MVIC and the reps equal or below 50 % of the first rep will be considered as a fatigue rep.
    


Intervention name(s): Neo-Russian; Aussie; RBS
Intervention type(s): Device; Device; Device
Intervention description(s): Subjects will receive Neo-Russian electrical stimulation with three reps (5 sec work x 120 sec rest), and the Maximal Electrical Induced Contraction (MEIC) will be measured. They will be asked how uncomfortable the stimulation was, using Visual Analogue Scale (VAS).
One week later, subjects will receive a fatigue protocol that consists in 21 reps (5 sec work x 5 sec rest), and the Maximal Electrical Induced Contraction (MEIC) will be measured for each contraction.; Subjects will receive Aussie electrical stimulation with three reps (5 sec work x 120 sec rest), and the Maximal Electrical Induced Contraction (MEIC) will be measured. They will be asked how uncomfortable the stimulation was, using Visual Analogue Scale (VAS).
One week later, subjects will receive a fatigue protocol that consists in 21 reps (5 sec work x 5 sec rest), and the Maximal Electrical Induced Contraction (MEIC) will be measured for each contraction.; Subjects will receive RBS electrical stimulation with three reps (5 sec work x 120 sec rest), and the Maximal Electrical Induced Contraction (MEIC) will be measured. They will be asked how uncomfortable the stimulation was, using Visual Analogue Scale (VAS).
One week later, subjects will receive a fatigue protocol that consists in 21 reps (5 sec work x 5 sec rest), and the Maximal Electrical Induced Contraction (MEIC) will be measured for each contraction.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Thirty male subjects, right leg dominant, will receive 3 types of electrical stimulation in a randomized order. Aussie current will be delivered by Aussie Sport (Ibramed) device, Neo-Russian by Neurodyn III (Ibramed) device and RBS by a Genesy (Globus) device.
MVIC and MEIC will be measured with an isometric dynamometer (3 reps x 5 sec work x 120 sec rest). The best rep will be used. Whenever the third one was the best, additional measurements will be taken until a decrease in torque will be obtained to determine the maximum. MVIC will be used for data normalization.
The VAS will be used to assess tolerance to each treatment. A ratio between MEIC and VAS will be calculated.
One week later, subjects will receive, ramdomly, a fatigue protocol with the three types of electrical stimulation that consists in 21 reps (5 sec work x 5 sec rest). The data will be normalized with the MVIC and the reps equal or below 50 % of the first rep will be considered as a fatigue rep.
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Basic Science
Keywords: electrical stimulation; Muscle Strength; Fatigue; assessments, pain