The life energy that flows through our bodies is called Qi and is channeled through energy channels in our body which are connected to the body's organs and senses. In the palms of our hands there are energy points and by rolling the balls in our hands these points are stimulated and improvement of ailments can be achieved (but by no means a solution for every disease).
For many centuries, these health balls have been used in Chinese medicine to improve flexibility and blood circulation in the hands and fingers.