According to Bernstein, EMS machines allow you to activate more muscle fibers than you could if you were to just do a standard strength exercise without EMS. "It's really much more complete in terms of individual muscles you're working," he says. At Epulse, you wear a vest and pair of shorts that have electrodes on them. Then, a trainer will walk you through a series of simple bodyweight exercises (lunges, pushups, squats, and crunches), and adjust the level of electricity sent to your muscles. This workout model might be somewhat legit: A 2016 study found that people who did a six-week squat program with EMS had greater strength improvements than those who did not use EMS.