Muscle Stimulation With Electricity

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By Mary Carpenter

After her 2021 post on workout-based electrical muscle stimulation (EMS), MyLittleBird Well-Being’s Mary Carpenter expected studio offerings to take off in the U.S., as they have in Europe. But as of summer 2024, there are few options: once highly touted franchises and studios have closed; and many that advertise “EMS” in fact offer different forms of electrical stimulation that are passive, used while lying down —mostly for pain or recovery following injury, also for passive muscle-building.

PARIS-BASED lawyer L.M. pays $55 for 20-minute studio workouts with a trainer twice a week, which she credits for greatly improved strength and body toning —more than she achieves from a daily swim of one mile, 45 minutes of hula-hooping or weight training. For “EMS workouts,” what looks like a police vest—with wide bands on the arms, quads and glutes—delivers small electric shocks purporting to offer the equivalent of 90 to 240 minutes of strength training in just 20 minutes. Trainers set the electrical dose and direct the accompanying exercises.

Resistance created by EMS makes physical movements—low-impact combination of lunges, squats and planks with some weight-lifting movements; or even Pilates or yoga—more challenging so that they feel more difficult and are more quickly fatiguing, writes Rachel Feltman in Popular Science. Doing a bicep curl with a five-pound weight while wearing the vest activates larger “fast-twitch” muscle fibers, which have more growth potential but are not stimulated by light exercises.

“The machine stimulates your muscles to make them prickle and twitch [and] my muscles would keep randomly twitching for a day or two after each session, writes Feltman. Exercise scientist Greg Nuckols told Feltman: “Your body builds muscles as it repairs damaged muscle fibers [which] will lead to growth…On the other hand, you could just do those bicep curls for more reps or with a heavier weight, and all those same fibers would eventually activate.”

EMS “indisputably cranks up the intensity of whatever you’re doing but…you could always just pick a more intense activity and save a few bucks…there’s nothing magical about electrical pulses,” writes Feltman. But she describes athletes, such as Usain Bolt, “who sometimes uses EMS while running on treadmills to increase his speed when unencumbered.”

Among potential problems with EMS are the effects may be temporary, and there is a risk of overdosing the electricity—hence the need for the presence of a trainer or other expert. And the biggest concern, rhabdomyolysis, can happen following any intense exercise, including running, as well as in spin classes and at CrossFit—any time building strength involves muscle damage. When muscles break down, toxic components of muscle fibers can impair kidney function resulting in symptoms that include muscle stiffness, pain and a change in urine color.

“Athletes and strength and conditioning coaches have been experimenting with EMS for decades now, but it’s still not very popular,” says Nuckols. His conclusion, after surveying available data, writes Feltman: “Too much comes from studies funded by companies with skin in the EMS game, while even more of it comes from small, imperfect studies impossible to generalize.”

But EMS has helped those wishing to build back muscles after an injury—as well as seniors with muscle atrophy—according to WB20 (“Whole Body EMS Workout in 20 minutes).” People who cannot do squats and lunges can do easier exercises, such as bridging. Studio workouts—with a trainer who sets the electrical dose and directs the accompanying exercises—can cost from $50 to $100 a session.

At the Washington, D.C. area-based Silafit Dimitar Pavlov has worked with athletes as well as clients scheduled for joint replacements. Despite online listings for studio classes, Silafit does not yet have a permanent location: instead, Pavlov can bring a “mobile unit” to your house at $99 for the introductory session and an additional $10 to $30 for each session after that. Also in the D.C. area, WB20 lists a studio in Ashburn, Virginia.

Shock Therapy, where Feltman tried EMS, was the first gym to offer it in the U.S., but has since closed. And although companies, including Manduu and Ohm, have over the past five years announced plans to expand throughout the country—including in D.C., Maryland and Virginia—only a handful of studios have opened, most in the western U.S.

In contrast to workout-based EMS, electrical stimulation that is employed passively comes in many forms. “E-stim” can play a role in physical therapy following injuries or surgery, while TENS—transcutaneous electrical nerve stimulation— works on nerves to help deal with chronic pain. TruSculpt Flex, another option, uses electrical stimulation but passively; while EmScupt uses electromagnetic stimulation, also passively and at such a low frequency that it may fail to stimulate muscle contractions at all.

For brain conditions from epilepsy to Parkinson’s disease, neuromodulation via electricity and magnets alternatively stimulates and inhibits neuronal activity in the cortex. Researchers have linked neuronal damage and death in the brain to depression and neurodegenerative diseases, such as MS, Parkinson’s Disease and Alzheimer’s (AD). But despite good results in small groups of patients, most neuromodulation techniques still await better documented proof of effectiveness.

“Life is nothing if not electrical,” writes Georgetown radiologist Timothy J. Jorgensen in his book Spark—as quoted in a New Yorker review by Jerome Groopman. Conditions like epilepsy and migraines may resemble “an electrical storm in the brain,” writes Groopman, who describes the early 20^th century “medical craze for electrical treatments to address anything from headaches to bad thoughts.”

For me, after discovering that a strong core depends on muscles like glutes—particularly weak in my case—I hoped to try one workout-based EMS session. But the only local option that responded to my queries, Silafit, involved a trainer coming to my house, which is not a possibility for me. If I travel to a city like Houston that has a franchise studio, I might try it there—though a better option might be a trip to Paris, some day!

—Mary Carpenter regularly reports on topical subjects in health and medicine.