Affiliations: [a] Irmandade da Santa Casa de Misericórdia,
Rehabilitation Service (ISCMSP), São Paulo, SP, Brazil | [b] Centro Universitário São Camilo (CUSC),
São Paulo, SP, Brazil | [c] Wilson Melo Institute, Campinas, SP, Brazil | [d] Irmandade da Santa Casa de Misericórdia,
Rehabilitation Service (ISCMSP), São Paulo, SP, Brazil | [e] Vita Institute, São Paulo, SP, Brazil
Note: [] Corresponding author: Dr. Thiago Y. Fukuda, Rua Dr. Cesário
Motta Jr., 112; São Paulo, SP, CEP: 01221-020, Brazil. Tel.: +55 11 7733
0607; E-mail: tfukuda10@yahoo.com.br
Abstract: BACKGROUND AND PURPOSE: Neuromuscular electrical stimulation
(NMES) is an important tool in clinical practice to improve the recruitment of
motor units. Optimal forms of NMES, as well as the optimal frequency to achieve
the highest torque with the least possible discomfort are not well established.
This study was designed to compare maximum electrically-induced torque (MEIT)
in the quadriceps, the maximum intensity tolerated by the subject, and the
level of discomfort generated by three types of stimulation. METHODS: Thirty subjects (mean age of 25.0 ± 3.0 years) participated in the study.
Each subject was submitted to three currents: medium frequency (2500 Hz)
modulated in low frequency (Russian Current), and two currents of low frequency
(50 Hz), i.e. without an intrapulse interval (FES), and another with an
intrapulse interval of 100 μs (VMS). The maximum voluntary isometric
torque (MVIT) of the quadriceps was measured. The MEIT, the level of
discomfort, and the maximum intensity reached were also measured while applying
the three types of NMES. The order of the tests was randomized and the torque
was normalized in relation to MVIT. RESULTS: The results showed no
significant difference between the three types of NMES in relation to the
generated torque. However, the subjects were able to tolerate a significantly
higher intensity with the medium frequency current, and suffered less
discomfort when compared to subjects exposed to low frequency currents. CONCLUSION: Russian Current, FES, and VMS can be used clinically in order to
increase the torque of the quadriceps muscle. However, we suggest using the
Russian Current in the early stages of a rehabilitation protocol because it
showed better tolerance by the participants with less discomfort.
