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
Nine-ball in a diamond-shaped configuration, with the 1 ball positioned at the front (toward the position of the breaking player) on the , and the 9 ball placed in the center. The physical rack used to position the balls is typically triangle-shaped, usually wood or plastic, and capable of holding all fifteen object balls, although diamond-shaped racks that hold only nine balls are sometimes used. The placement of the remaining balls is generally considered to be random. However, in some tournaments, the ball being to the lesser player must be one of the two balls placed behind the 1 ball at