More Muscle, Less Fat—Is This High-Tech Workout A New Fitness Answer?

What Is EMS?

Can It Help You Get More Muscle, Less Fat?

EMS gyms, classes and workouts are relatively new and still largely off the public radar in the United States, but they have been popular in Europe and other parts of the world for decades. The oversimplified explanation of the concept is that an electric impulse causes an involuntary contraction of your muscle similar to but more intense than what you experience while lifting weights or doing other strength training, giving your muscle the exercise without you doing much. In the 1960s sports scientists in the former Soviet Union discovered that EMS could boost muscle strength quickly and used it to train elite athletes for the Olympics, and an article on this history in the Physical Therapy & Rehabilitation Journal reported that one Russian scientist found force gains of 40% in the elite athletes using the technology.

In the 1980s medical devices using EMS for physical therapy and rehabilitation became commonplace, and if you’ve had knee or shoulder surgery you might already be familiar with the technology. In the beginning of this century the first full (mostly) body suits for workouts were introduced in Germany, spawning a massive new fitness trend—today there are thousands of EMS gyms across Europe and other parts of the world.

But as Brendan Kennedy, owner of EMS fitness brand Katalyst told me, in Europe these are sold as consumer electronics, whereas in the U.S. they are FDA-regulated medical devices, which greatly limited access for Americans. Katalyst was the first suit to get FDA clearance for sale to U.S. consumers and the first you could buy, while recent EMS gym chains in this country such as Body20, Manduu and Iron BodyFit provide class participants with suits. Katalyst has a model more similar to Peloton, where they sell the suit for use at home and support it with a robust app full of digitally connected classes, broken into four categories, strength, recovery, cardio and power, with many sub-options in each, such as abs or upper body.

In recent years technology has greatly changed the exercise and fitness industries. As a health minded person who wrote a bestselling book about food and what we eat, and whose life and work has been closely associated with outdoor sports, these are subjects I pay a lot of attention to. I recently wrote here at Forbes about the boom in high-tech exercise recovery, as well as an article about a science-driven fitness and longevity resort retreat in Palm Springs, and an AI enabled all in one home strength training platform. So, the promise of EMS training, supported by many recent scientific and medical studies, and tons of anecdotal evidence, got my attention.

Fast, Low Impact Strength Training For More Muscle, Less Fat

The commonality between the at home approach and the studio classes is that just about all providers target workouts of 25 minutes or less, and as the Body20 website explains, “EMS training activates up to 90% of your muscle fibers in just 20 minutes, offering a fast, efficient way to build strength, improve endurance, and achieve your fitness goals.” Manduu classes are 15-minutes, and the brand claims that “When the brain sends a signal to a muscle, only about 65% of muscle fiber is activated. By contrast, the external EMS stimulus penetrates nearly 100% of muscle tissue. This produces a workout that is simultaneously ultra-low impact and incredibly effective, gentle yet intense.” IronBody Fit comes from Europe (France), has 250 studios worldwide, and claims that 25 minutes of EMS equals a 4-hour conventional strength training session. Most basic Katalyst classes are 20-minutes long, but their extensive library also has lower intensity recovery and cardio add-ons of 5 or 10 minutes and these can be combined to suit users’ goals.

In the U.S., EMS sessions are especially popular with professional athletes and celebrities, and USA Today reported that actor Tom Holland used it to get ripped to play Spider Man and Kendall and Kyle Jenner did an EMS workout on The Kardashians, while supermodel Cindy Crawford was an early investor in Katalyst. Some of the biggest sports stars including Usain Bolt, Rafael Nadal and Christiano Ronaldo have been cited using EMS workouts. George Clooney bought the Katalyst system and told Esquire in 2025 that “My arms are twice the size they’ve ever been. It’s crazy.” There are multiple specialty EMS gyms in New York and Los Angeles, but it is still between hard to impossible to find elsewhere in this country, which is the big appeal of Katalyst, the first at-home product, and one that has been growing for years. In addition, with gym classes often running around $100 a session, the payback on a complete Katalasyt system ($3000) is less than four months.

Katalyst’s Kennedy is a lifetime fitness junkie and self-proclaimed “gym rat” who has done long distance cycling events and Ironman Triathlons. But he told me that since getting hooked on EMS he has not done a conventional weightlifting gym session in four years—and for the first time in his life, in his Fifties, has “six-pack abs.”

It was his wife, a former professional ballet dancer, who discovered the company and EMS workouts. “She was essentially a professional athlete, extremely fit and had just had our first child. She was looking for something to give her that same workout and feeling of a satisfaction and she loved it. I had been going to gyms for 40 years, but during COVID gyms closed, and Katalyst was just getting FDA clearance to sell to consumers so we bought suits in 2021, and took them with us when we traveled around the world, and about a year ago we decided to buy Katalyst.” The portability of the lightweight package combined with the quick time frame of workouts and suitability to just about any hotel room make it extra appealing to frequent travelers.

“Everything we are learning about longevity tells us that strength is essential, at any age, but after we hit 40 or 50 it starts to decline. Same for people on GLP-1 drugs, and we’ve seen doctors telling people they put on those to get a Katalyst suit. It’s a way for people who don’t have time to go to the gym or don’t like going to the gym to get an extremely efficient workout in a short period of time, with a much lower chance of getting hurt.”

Whether at home or in a class setting, EMS workouts typically involve a series of light bodyweight movements, such as bicep curls or overhead presses with no weights, squats and standing “crunches.” The workouts require no weights or other accessories, though Kennedy says he sometimes uses very light dumbbells to help maintain better technical form, and his wife likes to use resistance bands. Workouts can be done entirely while standing in front of the screen, with no laying on the floor. It sounds too good to be true.

“Most fitness innovation is portability, ‘you can do this at home now’ or information, ‘you should do this,’ or motivation, ‘go do this,’ or entertainment that is distracting,” said Kennedy. “Katalyst has elements of that but the main thing that is different is that whether you are using some fancy piece of equipment on the wall or a fancy bike, you’re still doing the thing, you have to exert the effort. Katalyst is doing the thing to you. That’s really the key. I can have a workout on a day when I don’t necessarily want to workout and once I put on the suit I’m working out whether I want to or not, and in 20 minutes I’m getting the equivalent of a three to four hour weight workout. If I’m in the gym and do a curl, I’m using about 50% of my bicep. Even the best, most professional weightlifters might get to 55%. With Katalsyt, no matter how trained I am it’s firing 90% of that muscle. In a 20-minute workout, its four seconds on and four seconds off, so there are 150 impulses, and 26 pads for different muscle groups. That’s 3900 muscle impulses, but for me to do 3900 reps at the gym would take me at least four hours. It’s extremely efficient.”

Recent Studies on EMS Training

Numerous studies have shown the muscle and strength building effects of EMS compare favorably to considerably longer and more arduous traditional strength training sessions, and several also cite fat and visceral fat reductions. One conference paper aimed specifically at this followed a study group that did two 20-minute EMS workouts a week (basically what Katalyst recommends) for 10 weeks who were carefully measured before and after. The conclusion? “After 10 weeks of body weight training with WB-EMS, there is a significant difference in visceral fat between pre-test and post-test (P

A study available at the National Library of Medicine titled “Effects of Whole-Body Electromyostimulation versus High-Intensity Resistance Exercise on Body Composition and Strength: A Randomized Controlled Study,” compared doing a low-impact, low-effort EMS workout with a much more energetic HIT (High Intensity Training) strength workout in the gym. This was chosen because as the study says, HIT is widely considered the most efficient gym workout, “the gold standard reference HIT, for improving body composition and muscle strength.” Both groups exercised for 16 weeks with HIT participants doing workouts “to failure” and the study found nearly identical gains in muscle mass and strength, and concluded that, “In summary, WB-EMS can be considered as a time-efficient but pricy option to HIT-resistance exercise for people aiming at the improvement of general strength and body composition.”

Even most EMS proponents don’t claim that you can’t get as good a workout the old fashioned way, and most of the scientific literature I’ve found supports that, the notion that EMS is on par with longer and more strenuous traditional strength workouts. The advantage is that it’s much faster, much less strenuous, low impact, and if you don’t need to leave home and don’t need to have a room dedicated to machines and weight plates, you are much more likely to actually do it, which is a huge stumbling block in American health and fitness.

Another study, “Muscle Hypertrophy and Architectural Changes in Response to Eight-Week Neuromuscular Electrical Stimulation Training in Healthy Older People,” found EMS to be a “useful mean for combating age-related sarcopenia,” or loss of muscle mass and strength while ageing, and noted that, “Neuromuscular electrical stimulation (NMES), the application of an electric current to muscles in order to trigger muscle contractions, has been long used as an alternative intervention to resistance training in order to improve or attenuate muscle mass and strength losses. NMES has proven to be efficient across different populations, ranging from healthy adults and athletes to people with muscle weakness.”

Finally, a 2023 meta-analysis of 23 studies on EMS in Medicine Journal “concluded that WB-electromyostimulation has significant positive effects on muscle mass, body fat, strength, and power.” Those are all good things to have positive effects on.

I have been doing a lot of different kinds of exercise for decades and have been constantly tweaking and refining my workouts based on the latest research into health, fitness and ageing, and if it works as fans claim, I’m eager to add EMS to my routine. After all, I’m in the demographic that wants more muscle, less fat. Most of the studies I’ve read run from 8-16 weeks, so I’m going to give that a try with the Katalyst workouts, as where I live there is no gym-based class alternative. I’ll do it while using a smart scale with bioelectrical impedance analysis to track my muscle mass, body fat and visceral fat, and we’ll see how it goes.