Swimming is a calorie-burning champion that works every muscle in the body, says Jimmy Minardi, founder of Minardi Training in New York City. Kick up the expenditure like this: After 10 minutes swimming the crawl or breaststroke, grab a kickboard and do 10 minutes of kicking drills. "The kickboard isolates your legs, forcing you to expend more energy to complete a lap," says Minardi. For the next 10 minutes, do five 30-second speed bursts, with the last five minutes of that segment simultaneously using a more physically demanding stroke, like the backstroke or butterfly. "The harder the stroke, the more calories you burn," he says.
Total Time: 30 minutes
Estimated Calories Burned: 300-400