The story is that Russian strongmen used kettlebells in the 1700s to build strength, balance, flexibility and endurance. But nowadays you find these brightly colored, cannonball-shaped metal orbs in well-equipped gyms. Here’s how you use them to help shape your body.

Select smooth-handled kettlebells in sets of three different poundages. Many gyms usually have sets that include 5-, 8- and 10-pound weights.

Learn the proper technique. To avoid injury from the explosive movements of kettlebell exercises, you must first master basic techniques with a light load of weight. Then you can progress to heavier poundages.

Work with qualified and experienced instructors. According to the American Council on Exercise, you’ll get the safest, most effective kettlebell training from a certified fitness instructor. And don’t forget to ask if he or she regularly attends specialized sessions.