Melt Away Calories in Half the Time

This routine pushes the muscles in half of your body, and then allows them to recover while you push the other half.

Cycle through all four exercises, resting one minute between each, and repeat for 15 minutes. You'll hit every muscle and move at a pace fast enough to melt fat, says the workout's creator, Mike Robertson, co-owner of Indianapolis Fitness and Sports Training.

1. Lunge

Stand holding a dumbbell in each hand, arms at your sides, palms facing in.

Tighten your stomach as you step forward with your right foot, land on your heel, and lower your back knee to just above the ground.

Drive off your heel to return to the starting position.

Do eight to 12 reps with each leg.

2. Dumbbell Row

With a dumbbell in your right hand, place your left hand and left knee on a bench.

Keep your back flat and upper body parallel to the floor as your right arm hangs.

Now raise your right upper arm to your rib cage, squeeze your shoulder blade back, and lower it again.

Do eight to 12 reps with each arm.

3. Romanian Deadlift

Standing on your left foot, hold a dumbbell in front of your thigh with your right hand, palm facing you.

Keep your chest up and back flat, bend at the hips, and lower your right arm.

As you start to feel your hamstring stretch, straighten up again.

Do eight to 12 reps with each arm.

4. Push-Up

Lie face-down on the floor with your palms slightly wider than shoulder-width apart, fingers pointing forward.

Push yourself up until your body weight rests only on your palms and toes.

Lower yourself slowly until your chest barely touches the floor.

Repeat for eight to 12 reps.