Does the Arc Trainer Really Burn As Many Calories As It Claims?
First introduced by Cybex International in 2003, the Arc Trainer is a favorite among trainers because it offers a high-intensity yet low-impact workout. While it looks similar to an elliptical, the Arc Trainer uses a more natural movement pattern that feels like cross-country skiing or climbing stairs depending on the incline level. The Arc Trainer claims to burn 477 calories for a 150-pound individual after 30 minutes; compare that to a treadmill, which burns 425 calories (if you’re running an 8-minute mile), based on Cybex’s online calculator; or an elliptical, which claims to burn 324 calories, based on a formula from equipment manufacturer Octane Fitness. Anyone who’s used the machine, though, may be surprised because it doesn’t feel especially difficult (something called “perceived exertion”) — something Cybex mentions on its own website.
“I like the range of motion,” says Nick Clayton, personal training program manager at the National Strength and Conditioning Association. “It’s like running uphill or marching through snow without the impact,” he says. “I also like the fact that it emphasizes hip extension.” He explains that in hip extension, the glutes and hamstrings (two large, calorie-burning muscle groups) work to drive the legs backward while moving the body forward.
But how many calories does the Arc Trainer actually burn? And is the display on the machine to be believed? To find out, we spoke with Dr. Patty Freedson, professor emerita of kinesiology at the University of Massachusetts Amherst and co-author of a study that compared a group of exercisers’ actual calorie burn (based on heart rate and oxygen consumption) to the machine’s display. “We found a consistent overestimation of calories somewhere between 10 and 20 percent, [with an] even bigger discrepancy for overweight people,” she says. Freedson speculates the Arc Trainer may use an algorithm designed for running, even though running inherently burns more calories. “You never lift feet off the Arc Trainer, so you don’t move your body weight like you do running,” she says, which may explain the overestimation.
Dr. Scott Kieffer, professor of exercise physiology at Messiah College, presented a similar study showing the machines largely overestimated calorie burn, probably due to inaccuracies in the equation. “With even little mistakes in the machine, the end result can end up being way off,” he says. Dr. Michele Olson, a senior clinical professor in the department of sport science and physical education at Huntingdon College, says these discrepancies are common among cross-training machines like the Arc Trainer and ellipticals. Calculating calories for running and cycling is fairly straightforward, but Olson says “other machines have to use depth of the pedals, the geometry of the movement pattern, and the distance created to first estimate a completed distance, which then is transformed to calorie expenditure. The calorie readout is just that: an estimate.”
However, even if the numbers on the Arc Trainer aren’t 100 percent accurate, that doesn’t mean it won’t give you a great workout. Nigel Anderson of Gym Source likes that it’s a full-body exercise. “The more muscles you’re working, the more fat you burn,” he says. “That math will never change in a million years.” All of the experts we spoke with would still recommend it as a piece of gym equipment, even if the calories “burned” should be regarded more as a ballpark estimate. In fact, Kieffer says it’s his favorite machine and encourages users to “look at the big picture rather than what the machine says.” Dr. John Porcari, a professor in the department of exercise and sport science at University of Wisconsin La Crosse, co-authored a paper showing the Arc Trainer actually did burn slightly more calories than an elliptical at the same amount of perceived exertion. He recommends to continue using whatever machine feels best because ultimately “the best machine is one you’re going to use.” If it feels easier than you thought, keep doing it — just take the number with a grain of salt.