What are the discus, the circle and the cage?
Officials' detail · The throw · 2 of 3The men's discus weighs 2 kg and the women's 1 kg. It has a body of wood or another material and a metal rim. The circle is 2.5 m across inside. Every throw is made from a cage of netting, open at the front, that protects everyone nearby. An athlete's own discus may be allowed if it is certified and checked.
How it works
| Category | Weight | Diameter of the rim |
|---|---|---|
| Men | 2 kg | 219 to 221 mm |
| Under-20 men | 1.75 kg | 210 to 212 mm |
| Under-18 men | 1.5 kg | 200 to 202 mm |
| Women, including under-20 and under-18 | 1 kg | 180 to 182 mm |
- The discus: solid or hollow, of wood or other suitable material, with a metal rim whose edge is circular. Both sides are identical and smooth, with no dents, projections or sharp edges.
- The circle: an inside diameter of 2.50 m, give or take 5 mm. The rim is iron or steel, at least 6 mm thick and white, with its top level with the ground outside.
- The floor: concrete, asphalt or another firm surface that is not slippery, about 20 mm below the top of the rim.
- The white line: 50 mm wide, drawn out from the rim for at least 0.75 m on each side, level with the centre of the circle.
- The cage: "All discus throws shall be made from an enclosure or cage to ensure the safety of spectators, officials and athletes."
- Its shape: a U in plan. The mouth is 6 m wide and 7 m in front of the centre of the circle.
- Its height: the netting is at least 4 m high, and at least 6 m for the 3 m nearest the mouth on each side.
- Its strength: it should stop a 2 kg discus moving at up to 25 metres per second, without the discus rebounding at the athlete or going over the top.
- A shared cage: a hammer cage may be used for the discus.
- Whose discus: the organisers provide them. The technical delegates may let athletes use their own, or ones from a supplier, if they are World Athletics certified, checked and marked before the competition and made available to every athlete.
- How many: normally no more than two of an athlete's own for an event.
- No changes: "No modification shall be made to any implements during the competition."
Tricky cases
Can an athlete throw their own discus?
It depends on the competition. The technical delegates may allow it if the implement is World Athletics certified and has been checked and marked beforehand. It then has to be available to all the athletes.
Can another athlete use an implement that someone else brought?
Yes. An athlete's own implement is accepted on the condition that it is made available to all.
Can the discus and the hammer be thrown from the same cage?
Yes. A hammer cage may be used for the discus, with the larger circle fitted and the gates fixed clear of the opening.
Does a training ground need the full cage?
No. The rule says a much simpler construction may be satisfactory where no other event and no spectators are close by.
Why the rule exists
A throwing result means something only if everyone threw the same thing from the same place, so the rules fix the weight and shape to the millimetre and let only certified implements in. The cage is there because a discus released a fraction late leaves the circle sideways at speed.
Where it differs
| Where | What changes | Source |
|---|---|---|
| World Athletics rules | As above | TR 32.1 to 32.3; TR 32.6 to 32.8; TR 34; TR 35 |
| Training areas | A simpler cage may be used | TR 35.1 |
| New cage designs | May be certified if they protect as well without widening the danger zone | TR 35.3 (note ii) |
| Number of own implements | The technical delegates may allow more than two | TR 32.2 |
From the rule book
World Athletics, Competition and Technical Rules, 2026 Edition, Technical Rules 32.1 to 32.3, 32.6 to 32.8, 34 and 35, with the figures printed beside them. Checked 14 October 2026. Official document: World Athletics Competition and Technical Rules 2026 (PDF).