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
Water polo ball Water polo ball A water polo ball is a ball used in water polo and canoe polo, usually characterized by a bright yellow color and ease of grip ability, so as to allow it to be held with one hand despite its large size. Ball weight is 400-450 grams (14-16 ounces) and inflated to 90-97 kPa (kilopascals) gauge pressure (13-14 psi) for men and 83-90 kPa (12-13 psi) for women. Water polo balls come in two main sizes: a size 5 (68-71 cm in circumference), intended for use by men, and a size 4 (65-67 cm in circumference), intended for