In the previous column I discussed the benefits of the newest, old workout in the nation. Kettlebells, originally developed in Russia, are basically cannonballs with a handle. They have been around since the 18th century, but they were used most seriously in the 1970s by the Soviet Union’s sports academies to train athletes for strength and endurance.

Their uneven weight distribution is perfect for delivering an efficient, intense, whole-body workout.

Kettlebells can be a bit intimidating for the uninitiated. Several companies have addressed this by developing new kettlebell designs that are easier to use and fit more seamlessly into most homes and home gyms.

One of the most intriguing of these new designs is made by kor. It’s a kettlebell made of soft materials, so it is easy on floors and especially toes — kettlebells are notorious for causing stubbed toes.

The kor kettlebells can be set down without clanking and it’s almost impossible to hurt yourself by swinging the kor into an exposed kneecap or elbow.

The kor kettlebell comes in three weights and its maximum weight of 25 pounds may be too light for some. It also has a plastic handle, which is comfortable but gets slippery with sweaty palms.

If you’re a beginner, the kor is a great way to safely learn kettlebell techniques.

Bob Harper, a celebrity trainer, has designed a kettlebell with newer users in mind. It’s contoured rather than cannonball shaped. This is thought to help keep the bell part clear of arms and wrists when doing a kettlebell press. The base is encased in rubber, making it a little friendlier on floors than most traditional designs.

The Contour kettlebell also comes with an instructional video, helpful in teaching new users kettlebell moves. One drawback comes from the shape, which puts much of the weight on the edges of the bell.

The best kettlebell I tested was the most traditional. Dragon Door makes a line of kettlebells with great balance.

Thanks to a special casting process, their finish was also the best of all the bells I tested. It’s balanced, solid and durable.

Dragon Door kettlebells come in a variety of weights from 10 to 106 pounds.

It’s important for new kettlebell users to start off with light weights. The movements are all complex, involving multiple muscle groups. These movements are the key to kettlebells’ efficiency but also demand a high level of competence.

Ideally, athletes should seek guidance from a trainer before taking on a kettlebell workout. But once you’re ready, you may find out what the Russians have known for decades: Kettlebells are a key to taking your athletic performance to the next level.

Dr. James Glazer is a sports medicine physician for Coastal Orthopedics and Sports Medicine in Freeport. He serves as a consultant for the U.S. ski team.