Is it really effective to train with medium frequency devices?
In electrostimulation there is a lot of uncertainty regarding its use parameters and what type of parameters are the most effective. For example, if we focus on the frequency, we see how, according to the electrostimulation system that we analyze, it is defended that it is better to use medium frequency or low frequency currents.
So much so that in some cases we can find affirmations about the superiority of the medium frequency for sports training with respect to low frequency. But is this true?
Before continuing and solving this question, we will explain some basic aspects:
1- Electrotherapy: it is based on the application of controlled and safe electric currents to produce a positive effect on the organism. Normally this type of interventions seek to stimulate the nervous system, connective tissues and / muscle tissue.
Within the world of electrotherapy we can make a classification based on the electric wave frequency that we use. In this way we can talk about:
– Low frequency: between 1Hz -1000 Hz (1 KHz)
– Medium frequency: 1 KHz- 10 (KHz)
– High frequency: > 10 KHz
2- Frequency: is the number of electric pulses emitted per second. Its unit of measurement is the Hz. Depending on the number of Hz selected, we can have a greater or lesser effect on one type of muscle or other fibers and therefore the training effect will be different. Within the training field we usually use low frequency currents, although some devices use half frequencies. In no case is it recommended to use high frequencies or higher ranges of the average frequency to be used during a workout.
Training with electrostimulation: medium or low frequency?
In this article we will try to reach a clear conclusion with reference to six articles reviewed. In these six articles it is concluded in a consensual manner that there is not much difference between the medium frequency and the low frequency. However, we can point out several issues to opt for one frequency or another.
In one of the studies, it is mentioned that low frequency causes less discomfort than the medium frequency. And not only that, it can also be observed in another article that low frequency produces less muscle fatigue than the average frequency.
Knowing this, we can think that the low frequency is the most advantageous in terms of comfort, strength and muscular fatigue produced. Also, another article mentions that low frequency produces more muscle strength than the medium frequency. Finally, analyzing all the above we can think that the low frequency is advantageous compared to the medium frequency. That said, we have to take into account the objectives of our training and from there make decisions with common sense as professionals of physical activity and sports.
In addition to this, we see how the frequency ranges most appropriate for muscle training are those of low frequency (<1000 Hz). Specifically, the frequency range between 1-100 Hz has proven its effectiveness for use in sports training, and can be applied to both aerobic and strength resistance exercises.
To date, there is no evidence that using medium frequency devices has any benefit compared to the use of low frequency devices. In many measured parameters, better results are obtained using low frequency devices.
- F. Medeiros, M. Bottaro, A. Vieira et. al. (2017). Kilohertz and Low-Frequency Electrical Stimulation With the Same Pulse Duration Have Similar Efficiency for Inducing Isometric Knee Extension Torque and Discomfort. American Journal of Physical Medicine and Rehabilitation. 96: 388-394.
- M. Vaz and V. Frasson. (2018). Low-Frequency Pulsed Current Versus Kilohertz-Frequency Alternating Current: A Scoping Literature Review. Archives of Physical Medicine and Rehabilitation. 99:792-805.
- H. Iijima, M. Takahashi, Y. Tashiro et al. (2018) Comparison of the effects of kilohertz- and low-frequency electric stimulations: A systematic review with meta-analysis Hirotaka. PLoS ONE. 13:1-19.
- Y. Laufer and M. Elboim. (2008) Effect of Burst Frequency and Duration of Kilohertz-Frequency Alternating Currents and of Low-Frequency Pulsed Currents on Strength of Contraction, Muscle Fatigue, and Perceived Discomfort. Physical Therapy. 8:1167-1176.
- W. Scott, J. Causey and T. Marshall. (2009). Comparison of Maximum Tolerated Muscle Torques Produced by 2 Pulse Durations. Physical Therapy. 89: 851-857.
- V. Da Silva., J. Durigan., R. Arena et al. (2015). Current evidence demonstrates similar effects of kilohertz-frequency and low-frequency current on quadriceps evoked torque and discomfort in healthy individuals: A systematic review with meta-analysis. Physiotherapy Theory and Practice. 31: 533-539.