Kettlebells originated in Russia where farmers used iron balls to weigh crops. These bells evolved as objects used by circus performers and ultimately became instruments for exercises to develop muscle strength, stamina, stability and grip strength. Use of kettlebells also supports cardiovascular and pulmonary fitness.The contemporary balls are composed of iron or steel, range in size from 4 inch diameter to 12 inches, and weigh from 2 kilograms to 30 kilograms or more. They are employed in physical training regimens for individuals and they are used in competitive workouts among professional athletes.
