If you loved the burn of high-intensity interval training but dropped it because it started to feel like exercising in a torture chamber, listen up: A new University of Copenhagen training plan lets you get the most out of HIIT—without killing your motivation.

For eight weeks, 28 of 132 runners tried the (confusingly named) “10-20-30” protocol, which has three steps: running, cycling, or rowing at an easy pace for 30 seconds; at a moderate pace for 20 seconds; then all out for 10 seconds. (So, yeah, even though it's called the "10-20-30" protocol, you're actually doing intervals in a 30-20-10 pattern.) Subjects did this five times with no rest, took a two-minute break, then repeated it five more times—for a total of 12 minutes.

After two months not only were nearly all subjects still in the program—there was almost no falloff—they’d also cut about 38 seconds off their 5K times. The control group? Nada.

“The fact that you work really hard for only 10 seconds makes it very easy to do,” says U.C.’s Lasse Gliemann, Ph.D. “You don’t need a huge amount of willpower to finish a 10-second sprint.”