CARDIO IS THE cornerstone to any good weight-loss plan—especially intervals, in which you alternate going as fast as possible with brief periods of recovery. To help you make those sprints as effective as possible, we asked Phil Campbell, an interval-training expert and author of Ready, Set, Go! Fitness for his best fat-burning tips.
“You want to take your heart rate up progressively,” Campbell says. “Focus on large muscles like the hamstrings and quads. Try ankle circles, knee circles, some light hip stretches—they all get your muscles and ligaments prepared to fire faster.”