Risks and contraindications of muscular electrostimulation

Muscular electrostimulation, like any other training method or electrotherapy system, even though is beneficial (we’ll speak about this on another article) has its potential risks and adverse effects, some of them partial and other absolute. All professional trainers, dealers or users must know them in order to give advice and or practice in a safe way.

We´ll dive deep into the risks and adverse effects, but you will also find useful information about the differences between analytic electrostimulation, with brands as Compex or Chattanooga, and global muscular electrostimulation, also known as electrofitness, electrostimulation suits or vests and scientifically known as whole body WB-EMS electrostimulation.

Curso de electroestimulación aplicada al core por Juan Peris


Some concepts that every user should know before diving deeper into EMS:

  • Users must know beforehand which device they are going to purchase; a high quality muscular electric stimulator must have:
    • Direct electric pulse generator
    • Rectangular, bi-phase, symmetric and compensated waves.
    • Dealership permits and technical service.
    • Please note: We are not trying to complain in this article, but we think that users have the right to know that there are brands in the field which sell electrostimulation equipment without fulfilling the minimum security guarantees. This article is based upon well-known quality brands which fulfill all the homologations. More severe injuries caused by low-quality equipment such as skin burn will be obviated.
    • Users are also responsible for acquiring or purchasing services related to muscular electrostimulation, in this way should always demand graduate training professionals with specific MES training.



So let´s get a better view of the risks and adverse effects of muscular electric stimulation:



Muscle fibers injury:

  • Applying electrostimulation without taking into consideration logical progression criteria can generate an excess of muscular tension that most of the times, due to a dynamic acceleration and even more if the muscular group being trained is an eccentric phase, can end up in hamstring injury or even worse, myopathy or torn muscles.


  • Performing a training to improve the user’s tolerance can lead to rhabdomyolysis, a pathology caused by the excessive muscular fiber decomposition which drains the content of it into the bloodstream at such a high level that the kidneys cannot filter, saturating them and so generating this illness. These substances which are derived from the muscular tissue amongst others are myoglobin (Protein) and CPK – Creatin phosphokinase (enzyme). To properly diagnose rhabdomyolysis CPK blood levels must be more than or equal to or 5 times higher to normal levels ( 0 – 195 UI/L in men, 0 – 170 UI/L in women)


Severe kidney fail:

  • Severe rhabdomyolysis can evolve in severe kidney failure. This will happen when CPK levels are above 25.000 UI/L.


Analytic Electrostimulation Vs. Electrical muscle stimulation suits:

  • Whichever is the electrostimulation training format chosen, the user must know that all safety and performance indications (this includes any potential injury risk) will depend on the knowledge and decisions that the trainer takes, this is not different from any other kind of sports training. Besides this, if a muscular electrostimulation suit has the capacity to actuate on a bigger amount or number of muscles, the probability to have high levels of myoglobin or CPK is higher.
  • Important: most of this undesired adverse risks can appear with any kind of sportive training which has been developed above the users’ limits and most probable when in dehydrated conditions or when following medical treatments with drugs even though keep training. We must once more remember that users must ensure to have the proper professional advice who performs a correct anamnesis and develops a proper training plan. Myox Institute has developed safety protocols which training professionals worldwide use with excellent results, even more, different electrostimulation suit brands are adopting these techniques as a reference. We recommend you to read this blog article: First four sessions with electrostimulation suits.





Training with muscular electrostimulation can produce adverse effects on our bodies, which mainly come from:

  • The adverse effect is produced directly from the electrical current or generator.
  • The physical effort itself. Most of them are similar to the ones produced by traditional training.


If you are a professional trainer this article might be of your interest: Electrostimulation course for critical/sensitive users. In it, you will find more detailed information about all the adverse effects of muscular electrostimulation.

Let´s get into potential contraindications with muscular electrostimulation, absolute or partial, due to analytic format or during training with electrofitness suits:


Users with pacemakers or cardiac defibrillator:

  • Compex electrostimulators consider users to have a partial contraindication if they have a pacemaker or cardiac defibrillator implants. This is due to the fact that this kind of devices can interfere with them and modify the normal function. Being the thorax the affected area this is hence considered as a partial contraindication.
  • Electrostimulation suits are considered to have more interaction with pacemakers and then the contraindications for users with them implanted are absolute. Even though the suit hasn´t the thorax electrodes active, this might have an electrode over the chest which with humidity produced by exercise can be accidentally activated. Bear in mind that if there is an active circuit nearby another which is not in use, due to the conductivity property of humidity the second circuit can become active.
  • Myox Institute strongly recommends not to use analytic tension over the thorax, abdomen nor arms with users using pacemakers as these are close to the chest.


  • Based on specialized doctor’s opinions, a severe epileptic seizure might be given when pulsing muscles with an electrostimulator. This is absolutely contraindicated.



  • Analytic electrostimulation on pregnant women is partially contraindicated, as we shouldn´t apply it on the abdomen but is safe to use on the rest of the body. Even though, Myox Institute discourages to use this on the thorax, lumbar or gluteal areas as they are too close to the fetus and the vaginal zone.
  • Contraindications of electrostimulation suits are similar to the ones explained before. Disconnecting the abdominal area electrodes would not be enough due to the electrical conduction property of humidity, deriving in the accidental ignition of them. Moreover, electrostimulation suits are a very tight type of clothes which can generate high pressure over the body, generating high levels of heat during training and if we are stimulating large muscular masses there would be a high blood demand which can cause to leave the abdomen with low levels of blood. With all, there is a high risk of abortion and therefore this is an absolute contraindication.


Abdominal or groin hernias and abdominal diastase:

  • Abdominal or groin hernias are considered as partial contraindication when electrostimulating on the abdominal area with equipment such as Compex or Chattanooga.
  • Using the same criteria as on other cases described, when using an electrofitness suit this will mean the contraindication is absolute.
  • Using the muscle electrostimulator will increase the pressure on the abdominal área increasing the risk of exacerbating the hernia.
  • Myox Institute, with electrostimulation courses (Myox EMS core) specially developed for training professionals, explains how to apply electrostimulation on abdominal area, positioning of the electrodes, electrical parameters and also positioning the user correctly (lying up against the floor the intra-muscular pressure will be reduced due to the effect of gravity, making the guts to lie down against the backbone) combining with breathing techniques, re-training the abdominal function, hypopressive exercises… with all, we have made out of electrostimulation a very useful tool with which to heal or recover from a hernia and abdominal diastase.


Positioning the electrodes on the front or lateral side of the neck:

  • Unless prescribed by a doctor or specialist, applying electrostimulation on this area is contraindicated as this area can react with muscular reflexes with a high risk of choking.


Cardiac Pathology:

  • Partial contraindication when applying analytic electrostimulation on the thorax, unless prescribed by a specialized doctor, indicating there is no interaction between electrostimulation and the pathological risks. We must remember that muscular electrostimulation is another way of physical training which is only capable to stimulate skeletal muscles
  • Absolute Contraindication when using electrostimulation suits.


Venous Thrombosis, thrombophlebitis and severe arterial obstruction:

  • Applying electrostimulation on affected limbs or at risk to have thrombosis or other venous disease is totally contraindicated. If the medical specialist determines or there are suspicions of the illness, because the blood count (haemogram) of the user indicates there is a high risk to suffer whatever type of thrombosis it is absolutely contraindicated to use electrostimulation; bear in mind the capability of electrostimulation to move blood, this could move a blood clot producing a thrombus and more severe, ictus and even death of the user.


Circulatory diseases:

  • Muscular electrostimulation in all of its variants is absolutely contraindicated when the user suffers chronic venous lack with important varicose veins. We endanger to magnify the varicose veins and increase the risk of thrombosis.



  • Muscular electrostimulation in whichever variant is absolutely contraindicated. This is a hereditary hematological disease on which users undergo coagulation factor replacement therapies which need physical exercise, never electrostimulating due to the vascular stress they could cause.


Infectious or febrile processes:

  • During infectious or febrile processes, we shouldn’t increase blood flow as this could cause the infection to expand over the organism; physical exercise and more precisely electrostimulation are absolutely contraindicated. If the pathogenic agent reaches the heart this could derive in severe cardiac diseases.


Arterial hypertension:

  • Applying electrostimulation to users who suffer arterial hypertension and which are not being treated by a medical specialist is absolutely contraindicated. Tension could alter during the training session and the user could be at serious risk.
  • On the other hand, when hypertension is controlled under medical prescription, risks associated with the use of electrostimulators varies. We understand hypertension when the systolic and diastolic pressure levels are at all times high, more precisely, above 149-95mmHg. We know that exercise exerts a benefit over cardiac capacity in the same way that muscular electrostimulation does. Nevertheless, Myox Institute considers arterial hypertension as a partial contraindication when applying muscular electrostimulation as this should only be used when:
    • Practiced under qualified professional supervision.
    • Avoiding isometries, or being this short and controlled.
    • Supervising that the user doesn´t get into apnea during the exercise.



Severe neurologic illness:

  • Muscular electrostimulation is absolutely contraindicated in all of its variants. Our recommendation anyway, is to perform a deep study of the user´s pathology as it has been demonstrated that muscular electrostimulation can improve the physical condition of users affected by multiple sclerosis.


Tumour or cancer diseases:

  • The effects of electric muscle stimulation have not been determined in users affected by cancer, also, this illness has a large range of typology. The risk encloses the fact that increasing bloodstream there is a bigger probability of having metastasis. Being cautious, we consider muscle electrostimulation on users with cancer to be contraindicated.

Swelling and autoimmune pathologies:

  • Moderate exercise is recommended for this kind of pathologies, and muscular electrostimulation also is, but we must remember that this is anyway considered partially contraindicated, as this should only be practiced under:
    • Strict supervision of a qualified trainer.
    • Moderate exercise including electrostimulation with Myox EMS safety protocols. Bear in mind that high intensity or high physiological impact produce stress over the organism and could lead to immune system depression, this is far inconvenient for users who suffer autoimmune illnesses or swelling pathologies as for example Polyarthritis.



  • Regular physical exercise is considered as an essential component in diabetes treatments and must be prescribed for the same reasons as it must be encouraged to the rest of the population, exercise reduces resistance to insulin, improving its effects. Muscular electrostimulation, as already said throughout this article is considered as another way to exercise our bodies; in fact, this has been verified by different studies concluding “after a training session with muscular electrostimulation, basal glycaemic levels where reduced significantly, as well as hemoglobin.” (Van Buuren y col, 2015).
  • In spite of the above explained, muscular electrostimulation has to be considered as a partial contraindication due to the following:
    • It cannot be used without control but always under qualified trainer´s supervision.
    • It may happen that various neuropathies caused by the use of insulin can derive in a sensitive lack which can alter the muscular response applied by the electrostimulator. Because, the trainer will need to have more diagnosis techniques, strategies which we teach in our muscular electrostimulation training courses: palpation diagnose, visual evaluation of the contraction level or articular range analysis amongst others.
    • Exercise doses have to be perfectly controlled as too much exercise could end up in hypoglycaemic shock.
    • Other safeguards to have in mind:
      • Check glycaemic levels before the electrostimulation sesión, from 100 to 150 mg/dl, levels are optimal for training.
      • never inject insulin in the muscular groups which are going to be trained.
      • Control glycemia during and after the training sesión.
      • If the training session is going to be considerably longer, we advise taking carbohydrate supplements.
      • Proper hydration at least two hours before starting the training session and during this.



Skin irritation, burns or wounds:

In case there exists some kind of damage or wound on the skin, we will not be able to apply any kind of electrode, other skin reactions such as allergic reaction or irritations should also be considered to avoid applying electrodes over the affected area.  Electrical circuits should be applied avoiding to get in contact with this area, hence being a partial contraindication for analytic electrostimulation.

  • When using electrostimulation suits, we will have to consider the characteristics and possibilities of this.



We would like to make a special remark now that we have explained all the risks and contraindications of muscular electrostimulation: “we don´t work with pathologies but with human beings”. With this, I want to express that pathologic symptoms don´t necessarily have to be the same on different people, there are other factors such as age, sex, background information, or even associated illnesses, basically, we must ALWAYS ask a medical specialist, when a user with the above-mentioned pathologies comes to us for an electrostimulation session. Even more, other factors such as cases of special population, or any other symptoms not considered as pathologies, ask for the advice of a medical specialist beforehand. In addition, we must obviously make an anamnesis or initial study of the user before starting with muscular electrostimulation.


My name is Juan peris, electrostimulation specialist and with this article about “risks and contraindications” I hope to have solved lots of doubts you have, you are welcomed to leave your comments and doubts below.


Juan Peris



Sports Sciences DEA

Physical Trainer – Col. 12.739

Physiotherapist – Col. 3.319

Myox Specialist in Muscle Electrostimulation

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