| 摘要 |
A sphere provided with an air chamber of a diameter of approximately 20-23 cm and equipped with a special valve to ensure that the air pressure, once inflated, is maintained properly. The exterior material of the air chamber is of synthetic canvas or other material like silicon rubber and has 24 conical protrusion of 2,3 to 3 cm in hight, and seperated from each other by about 8 cm. The diameter of the sphere will be of cm. The weight of the sphere may be varied according to the need, by changing the fibers of the construction. It may also be realized in different colors. The sphere, due to the protrusions and their numbers, acquires a dynamicbouncing behaviour. leading to increasing challenge for the reflexes of the players and the improvement of physical force due to the unpredictable bounce of the sphere. |
