It’s called electric muscle stimulation, or neuromuscular electrical stimulation, and in the last year has shocked its way into the top fitness trends. As noted by Women’s Health, celebrities across the globe are now using EMS to supplement existing workouts — trainers charging $100 or more per 20-minute session, promising everything from higher calorie burns to bigger muscle gains.
What’s the real story here? How does EMS work? How does it affect muscles during workouts? Does it have other applications? Most importantly, does this electro-excercise trend actually deliver results?
Wired Up: How EMS Works
The hype of EMS calls to mind late-night infomercials featuring “ab belts” and “muscle shakers” that promised to dramatically boost muscle mass or burn fat while users did … absolutely nothing. Prompted by a 2002 study that found many commercial products were both uncomfortable and poorly built, the Federal Trade Commission removed several neuromuscular electrical stimulation (NMES) products from the market. Now, the technology is back in vogue again with celebrity endorsements and seemingly better results. So, what’s the deal?
The science is fairly simple — users wear conductive suits comprised of small pads connected to a power-supplying console. Next, they complete basic exercises such as sit-ups, lunges and squats while the pads stimulate specific muscle groups, forcing them to contract. As noted by Men’s Journal, different movements cause different muscle fibers to engage. For example, slow-twitch muscle fibers come into play for push-ups, while fast-twitch fibers are used for heavy bench presses. EMS engages both sets of fibers at the same time to boost exercise impact and tire muscles more quickly.
According to a NCBI study, users did see improvement to their abdominal muscles after using EMS; participants reported feeling more “toned” and “firmed” and average waist circumference decreased by 3.5 centimeters. The data supports the assertion that electric muscle stimulation is doing what it claims.
But what does that feel like for users? First-hand accounts of authors and athletes trying EMS typically land on the same word: weird. The sensation feels like a buzzing or vibrating in targeted muscles, one that ramps up to moderate pain as the workout progresses.
Despite the water-soaked equipment — which helps conduct electricity — and copious amounts of sweat, there’s no “shocking” involved here, just a strange sensation of muscles compelled to contract on their own followed by significant fatigue. According to Men’s Journal, however, the gains made by EMS may not translate directly into better performance — machine-built muscles still need training to activate when under stress.
Use Cases: Training and Therapy
With celebrity backing and scientific evidence, EMS-specific gyms are quickly gaining ground. But it’s a mixed bag. While one study from Korea found that 20-25 year-old students completing a six-week course of EMS reported less anxiety and fatigue, Business Insider notes that at least one pad malfunction sent a user to the hospital with muscle breakdown. While this isn’t a likely outcome given the relatively low-power stimulation used, EMS technology is unregulated, meaning there are no hard-and-fast standards around safety or current levels.
Another potential use for EMS is therapy. There’s a longer history here with better results, while new techniques like transcranial magnetic stimulation offer potential benefits for cognitive function and mood adjustment. As noted by Science Direct, NMES “enhances muscle activation in weak or poorly innervated muscle groups, primarily used for patients with spinal cord injuries and cerebral palsy.”
A 2012 study found that EMS offered a way to preserve muscle strength in critically ill patients.
So what’s the bottom line for EMS technology? Unlike some other fitness trends, the science is there. Mild electric pulses can force unused muscle groups to contract and help increase total mass. For users, the feeling is typically odd but not awful, although concerns remain around standardization and rigor.
Therapeutic use, meanwhile, is more well-established thanks to physician oversight and the use of EMS devices to target specific outcomes rather than calorie burn or generalized strength training. Nonetheless, a 2016 study found muscle gains using EMS comparable to traditional high-intensity workouts, even though significantly less time investment was required by users.
Currently, EMS remains a technology bounded by practice and price — emerging standards and lowering costs, however, will spark the electro-workout market.