This all-in-one training technique uses explosive movements to power up your fat-burning cylinders (and enhance bone density). Here are five moves that build strength, agility, and a sexy midsection and lower body. Fast.

SINGLE-LEG SQUAT: GLUTES, HAMSTRINGS
Stand in a Smith machine, grip the barbell with your right hand, and hold a dumbbell in your left hand. Raise your left leg off the floor, foot flexed, and sink down into a squat until your right thigh is at least parallel to the floor. Drive through your heel to push up to the starting position.

Conditioning: 4×15 rest 90 seconds
Strength: 6×8 rest 2 minutes

SINGLE-LEG STEP-UP WITH KNEE DRIVE: GLUTES, HAMSTRINGS, QUADS
Holding dumbbells in each hand, stand with your left side next to a flat bench and place your left foot (your driving leg) on top of it. Push through the center of your driving foot, pressing your body straight up onto the bench while lifting your right leg to a 90-degree angle. Reverse the motion to step back down, repeat.

Conditioning: 4×12 rest 90 seconds
Strength: 6×6 rest 2 minutes

ALTERNATING JUMP LUNGE: CORE, GLUTES, HAMSTRINGS, QUADS, CALVES
Starting in a lunge position with your left leg forward, jump straight up and switch legs midair, landing softly in lunge position with your right leg forward. Immediately push off after landing to start your next jump, continuing to alternate legs.

Conditioning: 4×20 rest 20 seconds between sets
Strength: 6×12 rest 90 seconds

BULGARIAN LUNGE: SHOULDERS, CORE, GLUTES, HAMSTRINGS, QUADS
Holding a dumbbell in each hand, stand lunge-distance from a box or flat bench, facing away from it. Place the top of your foot on the box. Keeping your chest up and your front foot flat, slowly lower straight down into a lunge position until your front thigh is at least parallel to the floor. Drive through your front heel to return to standing.

Conditioning: 3 5×15 no rest, alternating legs
Strength: 6×6 rest 2 minutes

BOX SQUAT: CORE, GLUTES, HAMSTRINGS, QUADS
Holding a dumbbell in each hand, with the tops resting on your shoulders and your upper arms parallel to the floor, sit on the edge of a box or flat bench. Keeping your chest up and midsection tight, Drive through your heels to come to standing. Return to sitting and then repeat.

Conditioning: 5×10 rest 1 minute
Strength: 6×6 rest 2 minutes

Muscle & Fitness Hers