Burn, Baby, Burn: The Metabolism-Boosting Superset Workout

It's one of our most flab-melting routines ever: Eight of the best lab-tested toners mixed together to boost your metabolism, with no sweaty cardio required. You'll get up to three times more firming per rep as you torch a third more calories each minute -- during and after your workout -- compared with typical strength training. The skinny secret? Supersets! Cutting out downtime between sets, as with these alternating pairings of moves that work opposing muscles, "increases your metabolism not only because your heart rate stays higher throughout but also because the body works harder afterward to recover," says Mark Schuenke, PhD, assistant anatomy professor at the University of New England College of Osteopathic Medicine in Biddeford, Maine. Schuenke's research suggests that the bonus after-burn for a 140-pound woman can be up to 306 calories in the 24 hours postworkout. All you'll need is a set of five- to eight-pound dumbbells and a sturdy chair to net this slimming side benefit. Go on -- turn up the burn!