Kettlebells and medicine balls are both pieces of equipment that can be used to add resistance to your workout. Kettle bells are usually made of cast iron or steel. They have a handle attached to the top whereas medicine balls are leather, rubber or plastic (with or without handles). And they're designed to be used as a free weight. Both items of equipment come in different weights. So they can both be used to add resistance to exercises like squats, lunges and rotational movements. Often Kettle bells are more suited to swinging or ballistic exercises that involve more momentum and diversity. Medicine balls are designed to be held with both hands to enhance core stability and strength. Medicine balls are popular in team sports settings as they can be passed between partners during exercises. Kettlebells, on the other hand, are designed to provide continuous resistance throughout a movement. They target improvements in explosive power to help build muscle, improve endurance and increase flexibility.