Pulsed Current Versus Russian Current Effects in Healthy Young Subjects.

Summary

Low frequency pulsed current (PC) and medium frequency alternating current (Russian current - RC, 2.5 kHz) have been largely studied due to their clinical use. However, it is not clear which current is the most efficient due to the existente literature conflicts.Therefore, the purpose of this study is to compare the neuromuscular efficiency, evoked torque, current intensity, fatigability and level of discomfort between the PC and the RC in healthy young. The current types will be tested in the same participant by the intervention sequences randomization. On the first, second, third and fourth days, the maximum voluntary isometric contraction (MVIC), the current intensity level, discomfort level, evoked torque, and clinical and neuromuscular efficiency of each current will be evaluated. Anthropometric measurements will also be assessed on the first day. In addition, the current intensity required to produce a torque level of 20% of the MVIC, the current intensity required to generate a torque of 40 Nm and the maximum intensity tolerated by the participant will be evaluated. Three contractions will be recorded in each condition, and the level of discomfort will be assessed during the evoked contractions. Evoked torque will be evaluated at the maximum tolerated intensity level using the isokinetic dynamometer. Clinical and neuromuscular efficiency will be evaluated (1) at the current intensity necessary to evoke 20% MVIC, (2) at the current intensity necessary to generate 40 Nm, and (3) at the maximum tolerated current intensity. On the fifth and sixth days, muscle fatigue induced by the diferente current types will be evaluated. Fatigue will be evaluated with sufficient current intensity to generate 20% of the MVIC. MVIC will be performed before and after the fatigue protocol, and the fatigue will be determined by the relative variation of the MVIC before and after the fatigue protocol. Fatigue will also be evaluated through the evoked torque variation between the first and the last minute of the fatigue protocol, as well as by the total work generated in each protocol. Neuromuscular efficiency will be evaluated before and immediately after the protocol through (1) the ratio between input NMES current intensity and output evoked torque, (2) total work (area under the evoked force by time curves) generated during the fatigue protocol, and (3) by the changes in muscle architecture from rest to evoked contraction at the maximal current intensity.

Conditions

• Healthy Young
• Electric Stimulation Therapy

Interventions

DEVICE

Pulsed current

For stage 1 of the study, which corresponds to analysis of the evoked torque, evaluation of the discomfort level, current intensity, analysis of neuromuscular efficiency and clinical efficiency, 2 configurations (PC1 and PC2) will be used. PC1, will be set at a frequency of 100 Hz, phase duration of 1000 microseconds, ON-OFF time of 5s:10s. PC2, will be set at a frequency of 100 Hz, phase duration of 200 microseconds ON-OFF time of 5s:10s. For stage 2 of the study, which corresponds to the analysis of the fatigability level, only the PC1 configuration will be used.

DEVICE

Russian Current

For stage 1 of the study, which corresponds to analysis of the evoked torque, discomfort level, current intensity, neuromuscular efficiency and clinical efficiency, 2 configurations (RC1 and RC2) will be used. RC1, will be set to a frequency of 100 Hz, burst duty cycle of 20%, ON-OFF time of 5s:10s. RC2, will be set at a frequency of 100 Hz, burst duty cycle of 50%, ON-OFF time of 5s:10s. For stage 2 of the study, which corresponds to the analysis of the fatigability level, only the RC2 configuration will be used.

Sponsors & Collaborators

• Federal University of Rio Grande do Sul

  lead OTHER

Principal Investigators

• Marco A Vaz, PhD · Federal University of Rio Grande do Sul

Study Design

Allocation

RANDOMIZED

Purpose

OTHER

Masking

QUADRUPLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

35 Years

Sex

MALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2019-01-08

Primary Completion

2019-06-30

Completion

2019-08-30

Countries

• Brazil

Study Locations