Perhaps you’ve seen them lying around at the gym. They look like dumbbells with a handle. They’re small, but menacing. They’re called kettlebells, and they are your fitness friend.

Kettlebell training is gaining in popularity because of the myriad benefits, including strength, flexibility, mobility and cardio. All that, and you can get a strenuous workout in only about 20 minutes.

“Kettlebells allow you to build endurance, strength and balance of muscle groups,” said Christina Petrone, a RKC (Russian Kettlebell Challenge) and SFG (Strong First) certified kettlebell instructor from Little Neck. “People using kettlebells usually notice quick gains in muscle tone, which is a huge component of fat loss.”

The intensity of the swinging workouts also has benefits that go beyond the sometimes monotonous gym routine.

“They are second to none because they add explosiveness,” said Chris Cantwell, a RKC certified instructor from Massapequa Park, N.Y.

Quick and efficient

If you don’t have hours to spend at the gym, kettlebells can help you there, too.

“With most exercise, people use the excuse that they don’t have time,” said Petrone, who is also a licensed physical therapist’s assistant. “With kettlebells, that’s not the case.”

“You can get a full body workout in half the time of going to the gym,” Cantwell said.

Kettlebells can range from 5 to 50 pounds and are sold at most sporting goods stores. Having them in your home allows you do quick workouts without having to schlep to the gym.

“It’s a gym in your pocket,” Cantwell said.

While kettlebells build strength, there are also cardio benefits.

“If you do kettlebell swings for 10 minutes,” said Chris Cardinali, a RKC certified instructor, “you’ll be wiped out.”

“You burn more calories in a 20- or 30-minute kettlebell workout than if you were at the gym for 40 minutes on a treadmill or elliptical machine.”

Plus, added Cantwell, “It’s safer on your knees than running.”

Swing away

The foundation of all kettlebell exercises is the swing. It can be done with one or two hands and targets the hips, back, glutes, shoulders and legs.

“The beginner should learn the basics and practice them,” Cardinali said.

From there, Cardinali said, you can add other basic exercises such as the kettlebell deadlift and the Turkish getup.

The Turkish what?

“The Turkish getup is great for core mobility and stability in your shoulders,” Cantwell said. “It also helps your balance. I see a lot of strength coaches putting their athletes through a regiment of Turkish getups.”

The Turkish getup is an exercise where you start on the floor lying on your back. You cradle your kettlebell, raise it and then get to a standing position. Then you reverse the moves to return to the floor.

“It’s a move that we teach to everybody,” Cardinali said. “What’s great about it is that it has seven moves in it. The beauty is that it deals with primitive movement patterns and can be a screening for any movement dysfunction.”

Getting started

There’s something you must know about kettlebells. Treat them wrong, and they will hurt you.

“Kettlebells can be dangerous,” said Tristan Phillips, the head instructor and program director at Primal Strength New York in Ronkonkoma. “If you just start tossing around a 35-pound kettlebell, your back isn’t going to be happy.”

Phillips, who is a RKC and CK-FMS certified kettlebell instructor, emphasizes the need for proper form and good posture. Phillips teaches kettlebell classes for people of all levels.

“Focus on perfecting your technique,” Phillips said. “We tell people to stop before you get sloppy. You want your form to be sharp. Beginners should train with a certified SFG or RKC trainer.” (If you want to know more about kettlebell certification, visit dragondoor.com and strongfirst.com)

So, the question is, are kettlebells right for you? The answer, according to these trainers, is that they are right for just about everyone.

“Kettlebells can be used by people of all ages, physical stature and training level,” Petrone said.

There is even a DVD called “Kettlebell Boomers,” for those over 50, Petrone points out.

“My mom is 63,” Phillips said, “ and she takes my class.”