How EMS-trainings influence on muscular strength and sporting achievements
In sport, electrical muscle stimulation (EMS) is a very common practice. It initiates muscle contraction not through nervous system, but through the external factors. The effectiveness of this training technique has been examined in numerous studies. This article provides a general overview of the researches that have studied the impact of EMS-training on muscle strength increasing.
The content of the article
General concepts
The idea of EMS-training is the following: electrodes that are located at the surface, near the muscle motor point (Fig. 1) send electrical impulses with specified parameters. The use of EMS involves careful selection of stimulation parameters for optimal effect and risk minimization.
Fig. 1. Basic EMS-settings for the quadriceps femoris.
Stimulation parameters
Basic parameters that are regulated during EMS:
- Frequency (number of impulses per second)
- Current intensity or current amplitude
- Pulse characteristics (shape and duration)
- Operating cycle
- Slope (to reduce harshness and improve comfort)
- Materials, size and location of the electrode.
Currently, there is no consensus on the optimal parameters, and therefore there is some heterogeneity in EMS-studies. However, there is an unofficial statement regarding the basic characteristics of stimulation.
Most often, EMS-training uses two-phase symmetrical rectangular pulses with 50-100 Hz frequency and the maximum permissible current amplitude.
Also, it should be taken into account that tissues’ reaction to electromyostimulation depends not only on the parameters, but also on the person’s individual characteristics.
Physiological aspects
The activation of skeletal muscle under the action of EMS differs from similar processes under the action of internal impulses. This is mainly because of axons of large diameter respond to electromyostimulation more pronounced.
In their article written in 2005, Gregory and Bickel assumed that non-selectivity of muscle excitation under the action of EMS—that is, there is no sequence of muscle fiber engagement depending on type. In this regard, electromyostimulation can cause the activation of "fast" fibers at relatively low levels of force. Fundamental differences in the response of motor units to natural and external stimulation are presented in Table 1.
Table 1. Comparison of muscle responses to natural stimulation and EMS
A natural consequence of these features is higher metabolic cost during electromyostimulation, which provokes stronger and earlier muscle fatigue. According to the article written by Vanderthommen et al. in 2007, these differences in metabolic requirements are an argument for combining standard exercising and EMS-training.
Impact of EMS-training on muscle strength
The positive dynamics of various indicators of healthy muscle tissue under the influence of EMS-training does not exceed the improvement caused by traditional exercises. In their review of various studies, written in 2005, Bax et al. concluded that EMS-training was more effective than traditional one for patients with quadriceps architecture disorder, meanwhile for healthy people, standard trainings give the best result.
However, recent studies have clearly demonstrated the effectiveness of EMS-training for athletes, including professional ones (Table 2).
Table 2. Results of the studies on the effectiveness of EMS-training in various sports.
We have prepared a review article on the effectiveness of EMS-training in professional sports, in which you can find information about the use of EMS in different sports.
The increase in muscular strength caused by electromyostimulation is largely mediated by neural adaptation, especially in case of short-term programs. Longer training courses lead to morphological changes in the muscle tissue itself. An experiment conducted by Gondin et al. in 2005 showed that after 4 weeks of EMS-training, there was an increase in performance due to neural adaptation, without changing the morphology of muscles.
Replying to the question about the effectiveness of EMS-training regarding muscular strength, there are several options to consider:
- For healthy muscles, EMS-training is effective, but it is not superior to traditional training programs.
- For the weakened muscles, EMS is more effective than random exercises.
- In sports, EMS-training is effective in improving overall speed-strength performance.
Impact of EMS-training on sporting achievements
A number of studies have determined the positive impact of EMS-training on performance in various sports. There was a significant increase in speed-strength, and in some cases, in anaerobic performance. However, excessive use of electromyostimulation can worsen motor coordination.
Therefore, during the trainings with complex elements performance that require a high level of neuromuscular coordination, a positive result can only be achieved in case of combination of EMS and special exercises (for example, plyometrics).
As a practical recommendation for different sports, it is suggested to use EMS-training to increase speed-strength performance without reducing the frequency and duration of exercises specific to each sport. Because of this, it is better to conduct EMS-training at the beginning of the training season.
The main reason of the interest in using EMS-training in various disciplines is the ability to improve performance when a plateau level is reached during standard training programs. It is also worth to say that EMS-sessions do not require a lot of time. All this allows us to consider EMS-training as an addition to the traditional training process.
As an evidence, the study made by Willoughby and Simpson in 1998 analyzed the dynamics of results among 3 groups of subjects: the first group was using only strength training, the second – only EMS-training, the third – a combination of two programs. It was found that athletes who were engaged in complex program showed better results compared to the other two groups of subjects.
Another illustrative result is data from the study of long-term (12 weeks) EMS-training programs for rugby players. At the end of the 12th week, athletes who used electrical myostimulation during training showed better results in terms of non-specific indicators (jump height, maximum voluntary contraction). Meanwhile, for specific exercises (bout, sprint) no dynamics was found.
The results of the studies above allow to make a conclusion about the effectiveness of the combination of EMS-training and specific exercises in various sports.
Conclusions
Numerous studies on the effectiveness of EMS-training have shown positive results for healthy people, both physically trained and untrained. Differences in the results of individual performances may be caused by subjects’ training individual characteristics and the lack of the unified testing report.
The positive results of using EMS-training in combination with sport-specific exercises have been repeatedly confirmed. This allows you to include EMS in your training program. For example, Fig. 2 shows a schematic plan of combined training for basketball players.
Fig. 2. An example of an annual training plan for basketball players using EMS.
The heterogeneity of the results of the studies requires examining stimulation parameters and testing algorithms more careful.
Making an optimal EMS-training plan and integrating it into the training process will improve significantly the results of both physically untrained people and professional athletes.
The article is based on the study published in Strength and Conditioning Journal in 2011.
© emsnoble.com, 2023. All rights reserved. Copying the article or its parts is possible only with the link emsnoble.com
© emsnoble.com, 2023. All rights reserved. Copying the article or its parts is possible only with the link emsnoble.com