Kettlebells basically are hunks of iron with handles. Not very high-tech or cool-looking, but they have become popular in recent years. If you haven't tried kettlebells yet, this might be one of the most efficient ways to get a full-body workout with just one piece of equipment.

In one 20- or 30-minute routine, you get the benefit of strength training and an aerobic, fat-burning workout. You even can crank up the music and take it outside for a change of scenery.

For beginners, start with 5-, 10- or 15-pound kettlebells, available at local sports-equipment stores and most gyms. Start with two sets of 10 repetitions for each exercise. As you get stronger and more comfortable with kettlebells, work up to three sets of 10 or more.

1. Stand with feet wider than hip-distance and hold kettlebell handle with both hands at arms' length.

2. Bend at the hips into a squat, keeping shoulders back and chest up, moving kettlebell between your legs.

3. Swing up, standing tall, squeezing glutes, tightening thighs and lifting kettlebell to shoulder-height.

4. Repeat swing movement in a smooth, continuous motion.

1. Begin in a pushup position on your toes, holding a kettlebell in each hand, arms straight, shoulders over kettlebells. Keep abdominals tight and back straight.

2. Using core muscles to balance, pull one kettlebell back toward your rib cage, elbow pointed to the ceiling, then lower down.

3. Repeat with the other side. Make this a fluid motion, pulling one elbow back as soon as opposite arm has lowered and touched kettlebell to the floor.

1. Stand with feet hip-width apart, kettlebell in your right hand. Hold kettlebell at shoulder-height, elbow bent.

2. Lunge forward with the right foot, keeping core muscles tight, and press kettlebell upward until your elbow is straight.

3. As you step back to standing position, lower kettlebell to your shoulder. Repeat for 10 repetitions and switch sides.

1. Sit on the floor with knees bent in front of you, heels lifted a few inches off floor.

2. Grasp a kettlebell with both hands, one hand on each side of handle.

3. Bring kettlebell in front of your chest, elbows bent by your sides, and lean back slightly so you're balancing on your butt.

4. Rotate torso to the right, then come back through center and rotate to the left to complete one repetition. Note: Beginners may rest heels on the floor if necessary.