Exercise ball balls have been jumped across at 8.31 seconds.The record for the farthest jump between two Swiss balls was also made by Neil at a distance of 2.3 meters in 2012 A primary benefit of exercising with an exercise ball as opposed to exercising directly on a hard flat surface is that the body responds to the instability of the ball to remain balanced, engaging many more muscles. Those muscles become stronger over time to keep balance. Most frequently, the core body muscles — the abdominal muscles and back muscles — are the focus of exercise ball fitness programs. A major
Bowling ball China were made of wood. In about 1906 the first hard rubber balls were produced, such as the Brunswick "Mineralite" ball, and these remained the standard until the 1960s and 70s. These decades saw the emergence of plastic (polyester) balls. In the early 1970s, they began experimenting with the hardness of the plastic balls. The reason for this is to allow the ball to "grab" the lane better. Plastic balls were difficult to hook on tough oil conditions. Until the 1970s, there were no rules regarding the hardness of the bowling ball's surface. PBA member Don McCune took advantage of