Discus

The discus throw is an athletics (track and field) throwing event. The discus, the object to be thrown, is a lens-shaped heavy disc with a diameter of 220 mm and a weight of 2kg (4lb 7oz) for the men's event, and 1kg (2lb 3oz) for the women's, with a smaller diameter of 182mm. In school track and field, boys typically throw a discus weighing 1.616kg (3lb 9oz) and the girls throw the 1kg women's disc. The discus usually has sides made of plastic, hard rubber, wood, or metal, with a metal rim and a metal core to attain the weight. Sometimes a discus will have a heavier rim in order to attain higher spin. A practice discus made of hard rubber is often used in high school; it is cheaper and more durable.

Discus throwing is an ancient sport. In the 5th century BC the sculptor Myron produced a statue of a discus thrower (Discobolus), which is world-famous today (although the technique obviously employed by that ancient thrower is no longer considered anywhere near optimal).

To make a throw, the competitor starts in a slightly recessed concrete-surfaced circle of 2.5 metres (8 feet 2½ inches) diameter. They typically wind up while facing away from the direction of the throw. The thrower then spins around one and a half times through the circle to build momentum. The discus must land within a 40-degree or 60-degree arc marked by lines on the landing zone, and the competitor must not leave the circle until the discus has landed. The distance from the circle to where the discus has landed is measured. The competitor's best throw from the allocated number of throws is recorded, and the competitor who legally throws the discus the furthest is declared the winner.

The basic motion is a forehanded sidearm movement. The discus is spun off the index finger of the throwing hand, spinning clockwise when viewed above for a right-handed thrower, and anti-clockwise for a left-handed thrower. As well as achieving maximum momentum in the discus on throwing, the discus's distance is also determined by the trajectory the thrower imparts, as well as the aerodynamic behaviour of the discus. Also, a faster-spinning discus imparts greater gyroscopic stability. The technique of discus throwing is quite hard to master and needs lots of experience to get right, thus most top throwers are often over thirty years of age.