It sounds futuristic and maybe even too good to be true: put on a suit that gently electrocutes your muscles, and you can maximize your muscle use and accelerate your results. However, electrical muscle stimulation has long roots in physical therapy, and there’s evidence that it can help you get the most out of a workout. Here’s what the science has to say about electrical muscle stimulation — also known as e-stim or EMS — workouts.
Electrical muscle stimulation, otherwise known as e-stem or electroshock therapy for muscles, is a well-established therapy that has historically been used for pain management and mobility. Now, the use of EMS suits can make your workout more challenging and, thus, more effective.
EMS works by sending low-frequency electrical impulses to your muscles, causing them to contract. This makes EMS workouts a viable way to increase the efficiency of your workout in less time.
Does EMS work? The evidence suggests that it does if you’re pairing it with the right exercise routines, but it’s important to use them under the supervision of a trained individual to ensure both their safety and efficacy.
In this article, we'll discuss how electrical muscle stimulation works and how it is being applied in the fitness space in EMS training to increase the efficacy of some workouts.
What is electrical muscle stimulation?
Electrical muscle stimulation, also known as “e-stim” or simply “EMS” for short, delivers mild electrical impulses to your muscles.
These electrical impulses, delivered via electrodes attached to your skin from an EMS machine, cause the targeted muscle groups to contract. This is similar to how your brain sends electrical impulses to your muscles to cause a contraction.
Electrical muscle stimulation has historically been used as a therapy for pain management and to help improve mobility for certain patients. However, e-stim is now also being used in conjunction with workouts to accelerate results. In EMS workout training, you wear an EMS suit with electrodes throughout rather than in one targeted area, delivering electrical impulses to muscles in your entire body. With the addition of these electrical impulses, more of your muscle fibers are activated during movement.
What does e-stim feel like?
Because e-stim causes your muscle fibers to contract, you might feel a tingly, “pins and needles” sensation. In addition, if you’re using an e-stim suit during a workout, you may find that it adds more resistance to your regular movements, making movement more challenging.
Does EMS workout training work?
Yes, it works! The idea behind EMS workout training is that it can recruit more muscle fibers than working out alone. This can lead to a more challenging workout with more resistance, hypothetically leading to a more effective training session. The use of an EMS suit can be paired with a variety of workouts, from resistance training to cardio.
What the science says about EMS
Plenty of scientific evidence from small studies suggests that using an EMS suit or EMS machine during exercise can make your regular workout routine much more effective due to the increased involvement of your muscle fibers. This effect can also be seen in a variety of subjects, from individuals without any history of athletic training to elite athletes.
A 2016 study divided 20 athletes into two groups, one that did strength training alone and one that did the same strength training routine with the addition of EMS to their leg and trunk muscles. After a six-week period, they found that the participants who used EMS saw better improvements in their squat strength than participants who did not use EMS along with their training.
There’s also evidence that high-performing athletes may benefit from adding EMS to their regular routines. A systematic review found that trained and elite athletes could significantly enhance their strength levels when using whole-body EMS. In fact, they increased their strength to the same extent that untrained subjects were after EMS training. The findings are significant because untrained subjects tend to progress at a faster rate than athletes who are already at a high level of fitness.
In otherwise sedentary individuals, neuromuscular electrical stimulation led to increased oxygen consumption and subsequent energy expenditure, i.e., increased calories burned — a significant factor for weight loss. However, the study showed no significant improvements in body composition or weight.
Can EMS replace the gym?
No. It can not replace the activities performed in the gym. However, some evidence suggests that EMS can be similar to certain exercises. For example, when compared to HIIT-resistance exercise, electroshock muscle therapy was comparable for changes in lean body mass, leg-extensor strength, and even body fat.
Even more interestingly, electroshock therapy for muscles seems to have potential uses for people who can’t otherwise work out. For example, a study found that electrical muscle stimulation was effective in improving the strength of critically ill patients and may also have applications for muscle strength preservation in muscles that were not directly stimulated.
However, if you are an otherwise healthy adult aiming to increase strength, lose body fat, and/or increase muscle mass, there isn’t enough evidence to suggest that you can rely on an EMS suit alone for any significant changes. Even though there are individual trials and studies suggesting that it can be effective, there are still not enough randomized controlled studies to draw a definitive conclusion about the efficacy of EMS.
For the best results, you’ll want to use both to get the most out of your EMS training (i.e., wearing an EMS suit while working out). This can shorten the time you spend in the gym and make your workout more effective, without replacing it completely.
Is it safe to do an EMS workout?
Electrical muscle stimulation workouts should be fairly safe for healthy adults. Still, it’s important to make sure that you’re using an EMS suit with the guidance and supervision of a knowledgeable trainer to determine the correct voltage for both efficacy and safety.
Electrical stimulation that is too weak may not add enough to your workout for it to be effective. However, incorrect use can has been linked to muscle damage. In the worst cases, EMS workouts have been linked to rhabdomyolysis, a serious form of muscle damage that can be life-threatening.
Who should avoid EMS?
Because EMS involves the use of electric currents delivered to your body, you should avoid EMS workouts completely if you are:
- Have a neurological disorder
- Wear a pacemaker or a defibrillator
- Are prone to seizure
Electrical muscle stimulation already has an established reputation as a means for physical trainers to help alleviate pain and increase mobility. Now, its ability to recruit more muscle fibers means that it also has potential applications for increasing the difficulty and efficacy of your workouts when used correctly.
If you decide that you want to use an e-stim suit to get the most out of your workouts, make sure to only use them under the supervision of a trained individual and to pair it with a good overall exercise routine to maximize its effects.
Do you burn calories with EMS?
There is evidence that the use of an EMS can marginally increase your energy expenditure. However, there isn’t enough evidence to say that EMS on its own is an effective weight loss strategy. EMS is not a HIIT workout or a type of cardio on its own. For the best results, use EMS in conjunction with other cardio and the correct diet if you’re trying to lose weight.
How should EMS feel?
EMS should feel intense, similar to a muscle spasm, but shouldn’t be painful. You may notice that your movements have more resistance. You may also feel more sore than normal after your workout, since you were recruiting more of your muscle fibers. EMS should be used under the supervision of a professional.
Can EMS training replace the gym?
EMS training should not be used as a replacement for regular exercise, since there isn’t enough compelling evidence to suggest that it can make changes to your body composition or strength on its own. Instead, use an EMS suit in conjunction with your workouts to make them more challenging and effective.
- Journal of Sports Science & Medicine. Effects of Loaded Squat Exercise with and without Application of Superimposed EMS on Physical Performance.
- Journal of Strength and Conditioning Research. Electromyostimulation--a systematic review of the effects of different electromyostimulation methods on selected strength parameters in trained and elite athletes.
- Sensors (Basel). Effect of Neuromuscular Electrical Muscle Stimulation on Energy Expenditure in Healthy Adults.
- Evidence-Based Complementary and Alternative Medicine. Effects of Whole-Body Electromyostimulation versus High-Intensity Resistance Exercise on Body Composition and Strength: A Randomized Controlled Study.
- Critical Care Research and Practice. Electrical Muscle Stimulation: An Effective Form of Exercise and Early Mobilization to Preserve Muscle Strength in Critically Ill Patients.
- BMC Complementary Medicine and Therapies. Effects of whole-body ELECTROMYOSTIMULATION on health and performance: a systematic review.
- BMJ Open Sport & Exercise Medicine. Side effects of and contraindications for whole-body electro-myo-stimulation: a viewpoint.