UNITED STATES – Shaped like a teapot without a spout, the kettlebell is an unusual fitness tool. Initially designed as a farm implement, it is unbalanced and awkward to lift and move. That is partly why it is so effective.

The handle of a kettlebell is thicker than that of a dumbbell or barbell, so swinging or moving it improves grip strength. Its centre of mass is farther from your hand, meaning your body has to work to stabilise the weight as you swing it, lift it and press it overhead.

But talk to kettlebell enthusiasts and most of them will say the same thing: The weight feels alive in their hands.

“What I liked about the kettlebell training was that it didn’t look like exercise so much as it looked like movement,” said Mr Os Aponte, owner and trainer at San Diego kettlebell training gym Iron Core, about the first time he tried it. “It’s very thoughtful. It’s very mindful.”

Origin of the kettlebell

The first thing to know is it is a kettlebell – like the one you ring – not a kettleball. The second is that it has been around for a long time. It first appeared in a Russian dictionary in 1704, where it was a counterweight for measuring crops. Before long, farmers were using them to show off their strength at farming festivals.

“You put a group of people together with some weights and it’s not too long before somebody says, ‘I can lift that more than you can,’” said Mr Brett Jones, director of education and a master instructor for StrongFirst, a strength-training school in Reno, Nevada. StrongFirst was founded by Mr Pavel Tsatsouline, who is widely recognised as the person responsible for popularising kettlebell training in the United States.

In the early 1900s, the Soviet army began to use kettlebells as part of its physical training and, eventually, organised kettlebell championships in the late 1980s. By the early 2000s, partly thanks to Mr Tsatsouline, kettlebells became a fixture in most gyms.

How kettlebells improve your strength and fitness

One reason for the popularity of kettlebells is their versatility. You can use them like any other weight for squatting, pressing or deadlifting. You can also get a cardiovascular workout and build explosive power with cleans (when the weight is lifted from the ground to the shoulders) or snatches (when it is lifted from the ground to over the head).

While most of these movements can be performed with a dumbbell as well, the thick handle and the offset centre of mass of the kettlebell strengthens your grip and requires you to engage your core muscles as you lift it.

“All kettlebell exercises are core exercises,” said Mr Aponte.

The swing, however, is where the kettlebell comes alive. In one fluid movement, you grip the weight, lift it and snap your hips in an explosive yet smooth movement. Learning how to use your legs and hips to change the direction of the kettlebell works many of the muscles in your body and elevates your heart rate with less impact to the body than other free weights.

A few small studies have suggested that kettlebell training improves symptoms of knee arthritis and boosts grip strength in older adults. The association between grip strength and longevity has been well documented.

Other small studies suggest kettlebell training improves aerobic capacity in female intercollegiate football players and performance in weightlifting and powerlifting. It is also accessible to beginners.

“The handle itself makes it so forgiving because you can grab it on the corner, you can grab it on the side, you can grab it on the top,” said Ms Damali Fraiser, a kettlebell and nutrition coach in Brampton, Ontario. “You don’t have to necessarily balance it centred as you might with a barbell or a dumbbell.”

Which kettlebell to use

To figure out what size to use first, find the heaviest kettlebell you can lift from your shoulder to overhead comfortably and safely three to five times. This will most likely be an 11kg kettlebell for women with some experience strength-training and a 16kg one for men.

Be sure to look for a cast-iron kettlebell made from a single piece of iron. Vinyl or plastic kettlebells get slippery as you perspire and the seams can damage your hands.

When you are ready to add other kettlebells to your collection, go up about 4.5kg for your next one. Then, add a second kettlebell the same size as your first to start swinging two simultaneously.

The foundational kettlebell movements

Those who are starting out will want to focus on three effective, easy-to-master movements – the deadlift, the swing and the farmer’s carry. When you first begin using a kettlebell, get used to how the weight moves, said Ms Fraiser. Start with movements that do not go overhead. Once you are comfortable, move on to pressing and lifting the weight overhead.

The deadlift

A deadlift involves lifting a weight to hip level. It is a functional, practical movement and, in kettlebell training, it is the first part of the swing. It is also often easier than other types of deadlifts.

To start, place the kettlebell between your ankles, feet hip-width apart. Bend your knees slightly, keeping your hips elevated and your back flat. Grab the kettlebell handle with both hands, keep your arms straight, tighten your glutes and core, and stand up.

The swing

Start with a deadlift to bring the kettlebell to your hips. Push your hips back, slightly bending your knees, and bring the kettlebell between your legs. Keep your back straight and use your core muscles and glutes to push your hips, straightening your knees and swinging the kettlebell forward.

Swing the kettlebell as high as it will go with the force of your legs. Try to build momentum as you swing the kettlebell back and forth between your legs and the front of your body.

The farmer’s carry

Start by placing the kettlebell on the ground by either side of your body. Bend your knees slightly, like in the deadlift, and reach down to grab the handle of the kettlebell. Stand up with a flat back and a tight core. Start to take small steps forward, keeping your core engaged to maintain balance.

Do not let the weight drag you to one side and keep your chest upright. You can march in place or walk forward.

Once it is time to switch hands, place the kettlebell on the ground by bending your legs and maintaining a flat back, and then repeat on the other side. NYTIMES