By Betsy Morris Jan. 8, 2023 9:00 am
One of the latest trends in boutique fitness is electrifying. Literally.
Called whole-body electrical muscle stimulation, or EMS, the technique requires users to wear an electrode-studded suit that attaches to a machine. The suit delivers electrical impulses that make each exercise more difficult as muscles fight against the impulses.
The result is a more efficient way to build muscle mass and strength,say proponents, who claim that one 20-minute session of whole-body zapping achieves the same benefits as two and half hours of conventional strength training. In the U.S., the workouts are offered by about 400 fitness centers, spas and other outlets, and do-it-yourself home training kits are proliferating online.
Yet whole-body EMS isn’t a shortcut to a Marvel hero’s physique, scientists say. Regulators have warned the equipment can be dangerous, with risks including muscle damage or burns.
Clients work out with an electrical muscle stimulation device at a Chicago facility.
Whole-body EMS is attracting more attention from researchers studying whether the technique might benefit people who don’t or can’t exercise. Some doctors are investigating whether it can decrease inflammation in the obese and frailty in older people.
A small study presented at an American Heart Association conference in November suggested that whole-body EMS might benefit the heart. Twenty-four young, healthy adults who did 20 minutes a week of squats, lunges and bicep curls using electrical stimulation recorded greater improvements in waist and hip measurements, cholesterol levels, aerobic capacity and other indicators of cardiac health than a second group that did the same exercises without stimulation, according to the findings, which haven’t been published in a scientific journal.
Small studies like this suggest the approach might hold promise as a supplemental treatment for cardiac patients who don’t get the exercise they need, says Jaskanwal Sara, the Mayo Clinic doctor who conducted the research.
Physical therapists have long used small devices to deliver electrical stimulation to parts of the body to improve range of motion, relax muscle spasms, increase blood flow and stave off muscle atrophy in patients who can’t exercise.
Sports scientists and entrepreneurs began to develop whole-body EMS for fitness nearly 20 years ago. Companies are beginning to sell devices for home use, but most whole-body EMS training is offered in supervised settings like chiropractors’ offices and spas or with a personal trainer. Trainers recommend no more than one electrified workout a week unless you are very fit, and caution that these workouts, like conventional workouts, require time for muscles to recover.
At Five Points Fitness, a fitness center that offers classes and training programs in Corte Madera, Calif., the cost of whole-body EMS sessions ranges from $130 per single session to $95 each for a package of 50 sessions.
Clients change into a leotard-like suit designed to prevent electrodes from direct skin contact. Over that suit, they wear a specially designed vest, and arm and leg straps that have been sprayed with water to boost electrical conductivity. Clients are hooked up to a machine and get into a shallow squat with a tennis ball in each hand.
Studies on the effectiveness of EMS training for improving health and fitness are mixed.
Joan Busby, one of the center’s trainers, adjusts electricity that alternates on and off every four seconds as she puts her clients through 20 minutes of squats, lunges and bicep curls. Lights on the machine alert clients the electricity is about to start and when it is on. Ms. Busby says she maintains communication with clients as she adjusts the intensity of the electrical current during their workouts, asking them to rate how the electricity feels on a scale of one to 10.
“Ten means ‘I can’t take it.’ Zero means ‘You forgot to plug me in,’” she says. Usually, she adjusts the levels somewhere in the middle.
Tammy Wilks Kornfeld, a 59-year-old client of Ms. Busby’s, began whole-body EMS several months ago to get out of a fitness rut. The stimulation makes a squat or lunge seem about 10 times harder, she says. In a bicep curl, she lifts a tennis ball instead of a weight.
“You would think you could do it forever but you can only do 10 or 15,” she says. “The feeling is not unpleasant but you do feel your muscles vibrating. It could be scary for some people.”
She says the exercise has toned her body, resolved most of her back pain and boosted her stamina for tennis.
Studies on the effectiveness of the method for improving health and building fitness are mixed. Some indicate whole-body EMS improves body composition and reduces fat, but others don’t. Many indicate the method builds muscle and strength, but they are small and based on different methodologies, making it difficult to precisely determine the benefits. The Mayo Clinic’s Dr. Sara and other researchers say that more study is needed.
Trainers recommend no more than one electrified workout a week unless you are very fit.
The equipment can be dangerous. In Europe, according to several studies, the devices have been associated with at least seven cases of rhabdomyolysis, or rhabdo, a serious medical condition in which damaged, overused muscles release substances into the blood that can harm the heart and kidneys.
Katalyst Interactive Inc., which sells training systems to use at home for about $2,300, advises customers not to overexert. The company says people who are pregnant, people who have pacemakers or metal or electronic implants, or people who have any kind of heart condition must not use its training system. The company also instructs them to remove jewelry, body piercings and other metallic objects because “stimulation should not be applied near metal.”
The FDA has approved a handful of whole-body electrical muscle stimulators for improving the performance of healthy muscles but not for weight loss. The agency notes that it has received reports of shocks and burns associated with some devices and of interference with pacemakers and defibrillators.
While the stimulators might be able to temporarily strengthen, tone or firm muscles, “these devices alone will not give you ‘six-pack’ abs,” the agency tells consumers on its website.
“Electrical stimulation won’t turn a sedentary person into an athlete,” says Damien Callahan, assistant professor of human physiology at the University of Oregon.
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