EMS Workout: Can Shocking Your Body in an Electric Suit Actually Give You a Full Workout?

By Christina Stiehl

What if a full-body workout was only a matter of hooking yourself up to a system of wires and electrodes, doing a few lunges and squats, and calling it a day? That seems to be the lofty claim of electric muscle stimulation, or EMS, machines, which are promised to deliver a rigorous workout in just minutes of simple circuit training. It's a fitness trend embraced by celebrities and athletes including Victoria's Secret models Alessandra Ambrosio and Romee Strijd, former professional hockey player Sean Avery, and even world champion sprinter Usain Bolt.

On these machines, people are hooked up to electrodes that attach near major muscle groups. The EMS delivers tiny pulses of electricity to the muscles, causing them to contract, similarly to how muscles contract after receiving signals from the brain, says Tedd Keating, Ph.D., associate professor of exercise science at Manhattan College.

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This is supposed to help strengthen your muscles, or so claim the clubs and fitness gurus that tout this device. The Core Club, a private members-only club in New York City which boasts a $50,000 initiation fee, charges around $145 per EMS session for members, according to the New York Post. Using the Miha Bodytec machine, members get strapped into a wetsuit-looking outfit and are hooked up to a network of wires and electrodes. A trainer controls the electric pulses on a control panel, which targets select muscles.

If being able to achieve muscle definition in just minutes sounds too good to be true, it might be. Overall, the research is limited and conflicting, and many are small studies that are looking at performance in well-trained athletes. For instance, one recent study in trained athletes (the abstract did not specify how many subjects were part of the study) found that 10 sessions of EMS improved their sprinting performance, and a 2012 review of 89 trials in healthy young adults found that EMS training at three to six weeks led to significant strength and speed gains, noting that trained and elite athletes were able to see just as impressive improvement in their performance as less-trained subjects even though they were already performing at a peak level. However, a 2017 study in 21 male cyclists found that EMS did not improve endurance or strength performance in a 20-minute time trial after four weeks of EMS. On the other hand, some of the more recent research, like this study looking at the effect of EMS on squat performance, supports the claim that EMS may increase strength, especially when used in tandem with traditional training methods as opposed to using EMS by itself. This is what many EMS sessions at fitness clubs offer: performing simple circuit training while hooked up to the machine.

For those who aren't looking for performance improvements, there's still not sufficient evidence to support EMS as being effective in body composition changes. While one small study in obese elderly women in Germany found that a weekly 20-minute EMS session significantly affected metabolic markers and waist circumference, and another found "positive effects" on decreasing abdominal fat in a study in 46 nonathletic elderly women, there's little research on other populations and widespread implications can't be extrapolated from these small, specific samples. Plus, there's no real evidence that EMS will increase your muscle mass, Keating says. That's because while EMS contracts muscles, it doesn't provide any resistance, explains Bob Girandola, Ph.D., associate professor in the department of human biology at University of Southern California. "When you send a signal, an electrical signal from the brain or the spinal column to a muscle, it contracts," Girandola tells SELF. "The idea being that you're sending these contractions, but doing that doesn't really do anything unless the muscle contracts against a resistance."

Although EMS can be good for sending blood flow to the muscles to prevent swelling and inflammation, Girandola says it likely won't help with muscle growth. "If you want to get a muscle to get bigger and you do muscle contractions, it doesn't get bigger unless you put a resistance to it," he explains. In other words, simply squeezing your muscle won't increase its size—you actually need to add enough of a challenge to stimulate muscle growth. (This doesn't necessarily have to mean lifting weights, either. Using your bodyweight, as you do during a pushup or squat, can be an effective form of resistance, too.)

EMS machines have been used in a rehabilitative setting for years, says Keating, and can be effective to prevent muscles from atrophying. For example, a 2014 study published in Critical Care Research and Practice found that EMS has beneficial effects on intensive care unit patients and could be an effective tool in muscle preservation. In addition, many physical therapists and other rehab professionals use EMS to enhance blood flow and reduce muscle spasms, and studies are looking at EMS and its effect on lowering other health markers like cholesterol or glucose levels. In the studies of elderly women mentioned above, the authors note that EMS may be beneficial in certain ways for obese, nonathletic people who are unwilling or unable to exercise.

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Girandola, who has been hooked up to an EMS machine before, says it's a pleasant feeling. "As long as it's not at really high voltage, [EMS] feels like...a massage without the manual manipulation," he explains. "You feel the muscles contracting without you having to do anything, but it's like a wavy contraction."

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In fact, it's not unlike the muscle-shocker ab belts that have been sold on late night TV infomercials for decades. Those battery-operated devices also deliver tiny currents of electricity to your muscles, claiming (incorrectly) to tone and define your abs while you can sit idly watching TV.

If you’re looking to really strengthen and define your muscles, Girandola says you’re better off taking the money you would spend on an EMS machine and instead invest it in a gym membership. He recommends resistance training in combination with aerobic exercise.

But if you’re curious to see how these things work—and don't mind shelling out more than $100 a session for an Instagram-worthy moment—Keating suggests proceeding with caution. "I would seek out someone who definitely has a lot of experience using them, placing the electrodes, placing them on the right site, using the appropriate intensities," he says. "I'm not sure I would recommend their use outside of the context of with a physical therapist or a certified athletic trainer."

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