Grab a long rope, loop its midpoint around a stationary object, take one end in each hand, and flail your arms up and down like a madman for 10 minutes. You’ve just gotten your workout in for the day—really! Rope training, a vigorous upper body exercise that tasks your core, shoulders, and grip strength, may flex your aerobic capacity as much as sprinting does, minus the stress on your lower body’s joints.   Researchers at the University of Minnesota in Duluth and Creighton University put the exercise to the test and found that the average heart rate of a handful of fit volunteers during a 10-minute block of rope training intervals was 86% of the maximum for their age. What’s more: the participants peaked out at an average of 94% of their maximum heart rates, according to the paper published by the Journal of Strength and Conditioning Research.  Rope training works your upper body in a way that standard, lower-body-focused cardio equipment doesn’t. There is no lull in the action, like you’ll find in weight training—it takes just as much energy to fling the rope up as it does to reverse the motion seconds later.   In fact, it’s so tough that researchers say you can’t keep up this workout for sustained periods like you can when running or cycling, and add that it may be too vigorous for people unused to exercise. Battling Ropes workout creator John Brookfield agrees that the workout is no walk in the park, but says anyone can do this goofproof workout.  “Even athletes say they can’t go more than a few minutes at first, but there’s really no way to get hurt,” Brookfield says.  Brookfield suggests tacking a ropes session onto the end of your regular exercise routine for maximum results, because the vigorous training technique increases circulation, which can in turn move built-up lactic acid out of your muscles.  “Just sustain for as long as you can, rest for a short interval, then go back to training,” he says. “Constantly try to train for longer periods of time; before you know it, you’ll be able to go a full 10 minutes.” More From Prevention: The Newest Cardio Core Exercise  Get a Flat Belly With Kettlebells Crossfit for Women Over 50