This is track and field event throwing in a pushing motion a round heavy metal ball as far as possible, called a shot or a shot put. The throw is taken from an inside of a circle of 7 feet diameter. The distance thrown is measured from a point inside the throwing circle to the nearest mark made by the falling of the metal ball. Two styles are being used in shot put, the glide and the spin. With these styles the aim is just the same, to release the shot with the maximum velocity at an angle of about 40 degrees. Top shot putters prefer the spin technique, but gliding is most popular to amateurs and women shot putters. The decision to glide or spin depends on the throwers size and power. Shot put competitions have been included in Olympic games and in athletic events of world athletic championship. In the competition, the ball weight differs for men, women, and their ages.