The kettlebell or girya (Russian: ги́ря) is a cast-iron or cast steel weight (resembling a cannonball with a handle) used to perform ballistic exercises that combine cardiovascular, strength and flexibility training.They are also the primary equipment used in the weight lifting sport of girevoy sport. Russian kettlebells are traditionally measured in weight by pood, which (rounded to metric units) is defined as 16 kilograms (35 lb).
By their nature, typical kettlebell exercises build strength and endurance, particularly in the lower back, legs, and shoulders, and increase grip strength. The basic movements, such as the swing, snatch, and the clean and jerk, engage the entire body at once and in a way that mimics real world activities such as shoveling or farm work.
Unlike the exercises with dumbbells or barbells, kettlebell exercises often involve large numbers of repetitions. Kettlebell exercises are in their nature holistic; therefore they work several muscles simultaneously and may be repeated continuously for several minutes or with short breaks. This combination makes the exercise partially aerobic and more similar to high-intensity interval training rather than to traditional weight lifting. In one study, kettlebell enthusiasts performing a 20-minute snatchworkout were measured to burn, on average, 13.6 calories/minute aerobically and 6.6 calories/minute anaerobically during the entire workout - "equivalent to running a 6-minute mile pace" Because of their high repetitions, kettlebell progression should start out slowly to build muscle endurance, support the joints and prevent injury.