Cvičenie na lopte

The distance between the shoulder and the wrist is the correct diameter of the ball. When you are sitting on the ball, your feet are on the ground and the angles of the hip and knee joints are 100 degrees. The correct seats on the ball is a dynamic seats. The ball is an unstable surface and sitting on the ball force to work the muscles of the abdomen and legs. The ball is „the cheapest active chair“.