The UW-LaCrosse team was headed up by John Porcari, Ph.D., and Chad Schnettler, M.S. They studied 10 volunteers (both male and female) between the ages of 29 and 46 with kettlebell training experience.
"They [kettlebell enthusiasts] make these all-encompassing claims about increasing your muscular strength, endurance and aerobic capacity with kettlebells, like, if you do this, that's all you need to do," said John Pocari. "So we wanted to look and see how much of an aerobic workout you really do get and how many calories you really burn."
"We estimated oxygen consumption and how many calories they were burning aerobically, and it was 13.6 calories per minute. But we also measured the blood lactate, so anaerobically they were burning another 6.6 calories per minute," Pocari said. "So they were burning at least 20.2 calories per minute, which is off the charts. That's equivalent to running a 6-minute mile pace. The only other thing I could find that burns that many calories is crosscountry skiing up hill at a fast pace."
The researchers say calorie burn is accelerated during a kettlebell workout because it's a total-body movement done in an interval-training format. "We knew it would be extremely intense," says Schnettler. "It's a quick workout, and you do get a big bang for your buck in a very short amount of time."
For more information, check out the study online, which includes a six-week kettlebell workout.