Balls are used in many different training exercises to challenge the body and strengthen muscles. They can be used for heart rate increasing exercises, to strengthen core muscles, for balance and coordination, for stretching, massage and much more. Some common examples of exercises using balls include stable ball exercises, ball crawl, ball wall ball, ball training for the back and seated ball exercises. Spiked balls or Blackroll balls are often used in massage to increase blood circulation and loosen the connective tissue around your muscles. Knob balls and tactile balls stimulate your fingers to turn around, for example in rehabilitation after a stroke.