Kettlebells might sound more like something you ring in the kitchen rather than a fitness tool used to get in shape.
But since they were named one of the top workout trends in December by the American Council on Exercise (ACE), which does a yearly survey of fitness experts and personal trainers, you have likely heard more about this conditioning method and, perhaps, even seen them in weight rooms and gyms.
A kettlebell is often described as looking like a cannonball with a thick suitcase handle attached. Often made of cast iron, kettlebells were said to first be used by the ancient Greeks. But they have been more recently popularized by their use in Russia and Eastern-block countries to develop whole-body fitness and core strength in athletes.
The United States has only caught on to kettlebells in the past decade or so, and 2009 marked their first appearance on the ACE fitness trends annual list, suggesting a growing interest in them.
But are kettlebells simply another fitness fad destined to have their brief moment in the limelight before they get retired to a home closet or sit unused in a weight room?
These days, kettlebells might be the trendy thing in the weight room, said Dave Knight, an athletic performance coordinator in the department of sports medicine at the University of Wisconsin Hospitals and Clinics in Madison. But while he has noticed that this Russian training method is finding its way into more fitness centers and is being used more by performance coaches, he said, "We don't use them here [at our fitness facility] because we have other modalities to help athletes develop power."
Although Knight called kettlebells a valuable help with strength training and cardiovascular conditioning, he'd prefer that people work with dumbbells instead.
Unlike dumbbells, which have a bar that distributes two weights equally, kettlebells have a thick handle above a single ball-shaped weight. The higher handle allows a person to swing the kettlebell more freely than you would a similar weight dumbbell.
And while dumbbell workouts typically feature more lifting of the free weight, Knight said, the kettlebell training might find you learning how to swing the weight between your legs, or out in front of you, or from right to left, or on a diagonal. "Swinging of a weight is considered a ballistic exercise, traditionally deemed unsafe," he said.
Ballistic exercises are considered more dangerous to athletes because they carry a higher risk of stretching joints and muscles beyond their normal range of motion, if performed improperly. ACE has cautioned in the past against certain ballistic stretching movements, as they carry a risk for muscle pulls and joint injuries.
Of course, you can still do all the usual lifts and moves you would with a weight, such as squats, snatches and dead lifts, with a kettlebell.
And kettlebells come in different weights and often have a color-coded rubber coating so you can quickly tell how heavy or light they are.
As Knight put it, kettlebells are a tool to use for strength training, if they are heavy enough. They can improve core stability, if your posture while using them is good enough, or can be used for power training, if you swing them safely. They even offer aerobic conditioning, if they are light enough so that you do frequent repetitions.
"They may be part of a program, but not the end-all-be-all," he said.