Don't be fooled by the kettlebell. The compact, cast-iron weight may look like something only sideshow strongmen can lift, but it's a come-one, come-all tool that offers every benefit of traditional strength training -- and then some. Used by the Russian army for conditioning, the kettlebell -- which looks like a cannonball with a suitcase handle -- can prepare you for daily challenges in ways that standard weight lifting can't.

If you're new to weight training, start with an 8- or 10-pound kettlebell; go for 15 if you strength train regularly. Do 2 circuits of the following routine -- developed by Cindy Lai, a personal trainer who leads boot camps in New York City -- resting 30 to 60 seconds between each exercise, 2 to 3 times a week. The payoff? A stronger core, more lean muscle, better posture, improved balance, and the strength you need to fight fatigue and stay energized all day.

What it does: Strengthens legs, hips, glutes, and core.

How to do it: Pick up kettlebell with right hand and lift it into a "rack" position (as shown). Keep wrist straight as you bend knees deeply and sink the hips back to 90 degrees. Return to standing to complete 1 rep. Do 8 to 16 reps, switch hands, and repeat on the other side.

What it does: This total-body toner develops power and speed.

How to do it: Start with feet slightly wider than hip-width apart and the kettlebell on the floor between them. Squat and grasp the kettlebell with your right hand. Engaging your legs and hips, swing the bell back through your legs and straighten up, swinging the bell forward into the rack position (see Squat in Rack Position on previous slide). Then flip the bell back over, straighten your arm, and lower the bell to the floor, returning to the start position. Do 10 reps with each arm.

What it does: Targets the core, shoulders, triceps, and back.

How to do it: Start in plank position with left hand slightly wider than your shoulder and right hand on the kettlebell. (You can lower knees to the floor if you need to.) With elbows close to your sides, do a push-up. At the top of the push-up, lift your right elbow behind you (about 6 inches), and then return to start. Do 3 to 5 reps and switch sides.

What it does: Strengthens and tones the core, especially the obliques.

How to do it: Sit with legs bent, feet on the floor, hip-width apart. Hold the kettlebell with both hands at chest level. Lean back to a 45-degree angle with a straight back. Twist from the waist and rotate your torso from the right side to the left for 1 complete rep. Do 8 to 16 reps.

What it does: Works the hips, hamstrings, glutes, and core.

How to do it: Start in a squat, holding the kettlebell with both hands in an overhand grip. Swing the bell back through your legs and rock back on your heels, then use momentum to extend your knees and hips and accelerate the bell to shoulder height. Bend your legs into a squat and move your hips back as you swing the bell back through your legs again. Be sure to keep arms and back straight, chest lifted, and shoulder blades back. Repeat 10 to 15 times.

What it does: Tightens upper body, lower body, and core; improves strength, balance, and tone.

How to do it: Start with feet hip-distance apart and the kettlebell racked on the right. Step right leg back and bend left knee to 90 degrees. Step onto heel of left foot to return to start, then press the bell straight up and pause for a moment, keeping the shoulder in its socket and wrist straight. Lower back to rack. Do 8 to 16 reps on one side, then switch.

"Kettlebell workouts burn a lot more calories than traditional strength training because you're raising your heart rate and using multiple muscle groups at once," says Lai. In addition to improving muscle endurance, strength, and cardiovascular capacity, she explains, they also increase flexibility, balance, coordination, and agility. 

While dumbbells have weight on both ends and a fixed center of gravity, kettlebells put the weight below your grip with a shifting center of gravity, mimicking the kinds of things you wrestle with in real life, like groceries and kids. Also, kettlebell exercises aren't static lifts but dynamic moves that build muscle while constantly challenging your balance.

No Room? No Problem
Want the benefits of different weights without all the clutter? Consider the Jillian Michaels Ultimate PowerBell (shown here), a customizable kettlebell that lets you swap out or add in plates as you get stronger, without taking up extra space in your closet.