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Training / February 2020
Dan Stahl, Reebok Contributor

Shock Value: What Is E-Stim Therapy and Does It Work?

Electronic muscle stimulators have been used in physical therapy for decades. Now they’re giving the fitness industry a jolt.

A trainer straps me into a full-body suit wired with 18 electrodes. Then he hoses me down—to improve conductivity, he explains. Either that, or he’s messing with the newbie. 
Next it’s into a darkened room with five spotlights on the floor, one for each class member. We take our places as the trainer calibrates our voltage, upping the intensity in our quads, glutes, back, abs, shoulders, chest and arms until we say stop. When he gets to my shoulders, they twitch involuntarily, so he makes the call for me.  
The class moves through familiar exercises: squats, lunges, curls, flyes. The alternative rock music is also familiar. The twist? We’re not using any weights. Oh, and every few seconds an electric current convulses us. 
Does it hurt? Not exactly. It’s a jabbing sensation, like someone’s poking my muscles rapidly. The pressure gets uncomfortable in my midsection, where it interferes with breathing. But our trainer says he can adjust the intensity whenever we need it, so I ask him to reduce it in my abs and back. Later, doing curls, I have him increase it in my biceps, which feels good. 
At the end of the workout, my suit is soaked with sweat. I’m surprised—dare I say “shocked”? Weightless squats and flyes hadn’t felt like much effort, but I guess I’d worked harder than I realized. 
Two days later, my body confirms it. I experience the deepest, longest, most satisfying post-workout soreness ever in my biceps, glutes and hip adductors. Extra satisfaction comes from knowing I helped bring on the biceps burn. 

What Is E-Stim?

The unorthodox class I took is known as electrical muscle stimulation (EMS), a fitness trend pulsing through Europe and now flowing to the US. The studio I visited, Shock Therapy Fitness, is in New York, but others have opened nationwide. Many shy away from words like “shock” or even “electric” in their name (can’t blame them), but whether they call themselves Personal20 or Manduu, EMS is what they offer. 
During EMS, your muscles are zapped with low-level electricity, making them contract. Normally that’s your brain’s job. If you want to squat, your brain tells your legs to bend by sending an electrical signal through your motor neurons. With EMS, the signal comes from a machine. The result: You muscles work harder and more efficiently, raising the intensity of your workout.
High-tech as it sounds, electrotherapy goes back two millennia. A first-century Roman doctor recommended putting an electric ray on patients’ heads for headache relief; the fish’s jolts were also prescribed for gout and rectal prolapse (Google if you dare). In the 1700s, a scientist started experimenting with electricity on muscles, and by the late 1900s, “e-stim therapy,” which rehabilitates muscles through devices known as electronic muscle stimulators, had become an accepted medical treatment.
Some pro athletes have made use of it, too. But it wasn’t until the 2000s that e-stim surged as a fitness trend in Europe, where a full-body EMS suit debuted in 2001, according to Ural Huseyin, Vice President of Training and Technology at Shock Therapy Fitness. (Previously, electronic muscle stimulators targeted only individual body parts.) 
Later that decade, a trainer for one of the world’s top pro soccer teams discovered that e-stim therapy worked so well for the players in rehab, he began using it on healthy players to increase their athletic performance and strength, says James Cousler, Director of Education at Personal20.
Now there are over 1,000 EMS studios around the world, including more than 50 in the U.S. 

Benefits of EMS

What is it about EMS devices that hooks people after they’ve been hooked up to one? Whether you’re an athletic superstar or a yuppie cramming in a workout between your day job and dinner reservation, EMS is a time saver. A class lasts about 20 minutes—hence studio names like Personal20 and Body20.
In those 20 minutes, claim e-stim advocates, the intensity of the e-current gives you a workout equivalent to 90 minutes or more of traditional exercise. You’re also activating both fast-twitch and slow-twitch muscle fibers, for a more complete session.
But the biggest selling point may be accessibility. “We have 85-year-old people do this; we have 18-year-old athletes doing this,” says Wiley Robinson, Manduu’s chief operating officer. Because EMS classes are low-impact and weights-free, almost anyone can participate. Robinson, who’s also a registered nurse, says, “You can come in with a busted shoulder and a bad back and still get your session done without loading your joints with weight or doing crazy movements.” 
That said, people with particular conditions should steer clear. These include epilepsy, cancer, heart disease, pacemaker implants and pregnancy. Robinson also urges anyone interested to confirm a studio’s EMS equipment is FDA-approved before using it. 

What Does the Science Say? 

Is EMS the boon proponents make it out to be? Although an established medical treatment, e-stim’s use as a fitness tool is less studied. But the little research that does exist suggests it works. A report in The Journal of Strength and Conditioning Research found EMS was effective for developing physical performance among athletes, and another study in the Journal of Physical Therapy Science found that it reduced obesity.
Huseyin, it goes without saying, is a big believer. But he wasn’t at first. “I didn’t believe in EMS at all,” he confesses. Then he suffered two herniated discs during a gym workout. “When I got injured, I was desperate,” he says. Too weak to lift weights, he turned to EMS. “Twenty sessions later, I was able to go back to the gym.”
At the same time, Huseyin admits, EMS isn’t for everybody. It doesn’t hurt, but it’s not exactly easy. In a class, “everyone has their own experience,” he says. “Some people laugh; some people scream.” 
I laughed—when I wasn’t struggling to breathe. 

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Training / February 2020
Dan Stahl, Reebok Contributor