Kettlebells are one of the hottest workout trends around, and chances are you've seen someone swinging these round cast-iron weights. They are most often used for explosive motions with a focus on whole-body conditioning, while dumbbells are usually (but not always) used to isolate and build strength in specific muscles. Experts say kettlebells and dumbbells bring different fitness gains, but they each deserve their own place in your home gym.
In 2010, the American Council on Exercise conducted a study with researchers from the University of Wisconsin to determine the benefits of training with kettlebells. Ten volunteers were tasked with performing "snatch" exercises, which involve swinging a kettlebell between the legs and then up over the head in a fluid, continuous motion. Meanwhile, researchers were measuring each volunteer's heart rate, oxygen consumption and blood lactate level to estimate their calorie burn. Researchers discovered that the volunteers burned an average of 20 calories per minute during a 20-minute kettlebell workout. The results were "off the charts," John Pocari, Ph.D., the study's lead researcher, told Ace Fitness Matters. "The only other thing I could find that burns that many calories is cross-country skiing up hill at a fast pace." The University of Wisconsin researchers concluded that kettlebell training provides a more vigorous workout than typical dumbbell exercises.
That said, it's hard to beat dumbbells when you want to build strength. Researchers at California State University at Fullerton found that exercisers who used traditional weights (including dumbbells and barbells) improved their squat strength by 14 percent, compared to only 4 percent for those who worked out with kettlebells. Men's Health has more details on this study.
The bottom line: Reach for the dumbbells when building strength is a priority, but pick up a kettlebell when you would like to have your workout multi-task--in other words, when you want your workout to provide both cardiovascular and strength benefits..
The best kettlebells
Ready to start shopping? Cap Barbell gets the best user reviews for its kettlebells, which range from 15 pounds (*Est. $30) to 70 pounds (*Est. $120). Reviewers say Cap Barbell kettlebells are comfortable to hold thanks to a smooth finish, although the paint can chip easily. The Marcy Kettlebell Set (*Est. $90) also earns high ratings from owners. The set includes four kettlebells -- 5, 10, 15 and 20 pounds. Beginners love the value, but a few owners say the handles are rough.
The best dumbbells, including the Bowflex SelectTech and PowerBlock Sport, are covered in our updated dumbbell report.