Ronzio O.A.1,2,3,4, Dandres R.Y.1, Gulisano M.1
1Instituto Universitario Fundación H.A. Barceló, Ciudad Autónoma de Buenos Aires, Argentina, 2Universidad Nacional Arturo Jauretche, Florencio Varela, Argentina, 3Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina, 4Universidad Favaloro, Ciudad Autónoma de Buenos Aires, Argentina
Background: Muscle strength is the amount of force generated by muscle contraction. It could be measured in isometric, isotonic or isokinetic activity, either manually or using a dynamometer.
The isometric dynamometer is a validated and cheap 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. To normalize the MEIC values, the MVIC is used in several publications.
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.
Aussie current is medium-frequency alternating current which consists in a sinusoidal waveform, 1 KHz carrier frequency, modulated in 50 Hz (4 ms. burst duration).
Neo-Russian current is also a medium-frequency current with a rectangular biphasic symmetrical waveform, 2,5 KHz carrier frequency, modulated in 50 Hz (50 % of duty cycle).
Rectangular Biphasic symmetrical (RBS) waveform is a type of Low Pulsed current LPC, claimed to be better than classical Russian Current.
The isometric dynamometer is a validated and cheap 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. To normalize the MEIC values, the MVIC is used in several publications.
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.
Aussie current is medium-frequency alternating current which consists in a sinusoidal waveform, 1 KHz carrier frequency, modulated in 50 Hz (4 ms. burst duration).
Neo-Russian current is also a medium-frequency current with a rectangular biphasic symmetrical waveform, 2,5 KHz carrier frequency, modulated in 50 Hz (50 % of duty cycle).
Rectangular Biphasic symmetrical (RBS) waveform is a type of Low Pulsed current LPC, claimed to be better than classical Russian Current.
Purpose: The aim of this work is to compare the effect of these three currents in the MEIC and tolerance.
Methods: This a randomized, transversal double-blind clinical trial. Thirty male subjects, right leg dominant, received randomly the 3 types of electrical stimulation. Before that, the MVIC was measured for data normalization.
The MVIC and MEIC were measured with an isometric dynamometer, model Isoforce, trademark Fisiomove. In both measurements, subjects were asked to perform three reps (5 sec work x 12 sec rest) and the best one was used.
To apply Aussie electrical stimulation, an Aussie Sport (Ibramed) was used. To apply Neo-Russian, a Neurodyn III (Ibramed) was used. To apply RBS, an Elite Pro 600 (Globus) was used.
The VAS was used to assess tolerance to each treatment. A ratio between MEIC and VAS was calculated.
GraphPad InStat 3.01 software was used for statistical analysis. Repeated measures ANOVA with post-test and Student-Newman-Keuls Multiple Comparisons Test were applied.
Results: The MEIC values were for Aussie 34,20 +/- 23,53; Neo-Russian 22,07 +/- 18,9, RBS 15,89 +/- 13,42. The statistical analysis showed that RBS Vs. Aussie P 0.001, RBS Vs.Neo-Russian P 0.05, Neo-Russian Vs.Aussie P 0.001.
The tolerance ratio values were for Aussie 6,78 +/- 7,97; Neo-Russian 4,24 +/- 4,37; RBS 4,76 +/- 8,11. The statistical analysis showed that the differences between RBS Vs.Aussie, RBS Vs.Neo-Russian, Neo-Russian Vs.Aussie were not significant (P>0.05).
Conclusion(s): Aussie current was the best to generate a greater MEIC, compared to Neo-Russian and RBS, with a statistical significant difference. This current was also the most tolerated one, with clinical but not statistical differences.
Implications: Most portable devices use RBS. This work demonstrated that this type of current for electrical stimulation is not the best one.
Funding acknowledgements: This work has been supported by Instituto Universitario Fundación H.A. Barceló.
Topic: Sport & sports injuries
Ethics approval: Ethics committee of Instituto Universitario Fundación H.A. Barceló has approved this work, document HSC 5745.
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