Exercise ball standard exercises, such as a push-up, on an unstable surface can be used to increase activation of core trunk stabilizers and in turn provide increased trunk strength and greater resistance to injury. Fitness Experts and some doctors also recommend sitting on an exercise ball instead of an office chair. That is based on the theory that the abdominal and back muscles are constantly engaged and active to maintain proper posture and balance on the ball. There is no scientific evidence of those benefits occurring by just sitting without additional exercises. However, some people warn against using a Swiss ball as
Speed-ball in a base from 40 kg to 90 kg. The ball is elliptic and is hit with a rigid plastic racquet with a small handle and a strings around 25 cm of diameter. The speed-ball court is about 6x4 m. for the single match and 8x6 m. for the doubles. Speed-ball is played alone (super-solo), with two players (single match), or four players (double match),or four players (relay) In "Super-solo", the aim is to hit the ball a maximum times in one minute. At first with the right hand, then a minute again with the left hand, then with two