The athlete may enter the circle from any direction but must leave from the rear half of the circle only. A line shall be drawn through the centre of the circle to indicate the portion through which it is permissible to leave the circle.
The throw must be commenced from a stationary position.
It is permitted during the course of a trial (after the trial has already commenced) to stop and place the discus down inside the circle until ready to resume the trial. This can only be done provided that no infringement has occurred during that particular trial, and this does not occur more than once in each trial.
The athlete must not touch the top of the circle or ground outside the circle during the throw with any part of the body. The athlete is allowed to touch the inside of the steel band if this has been used in the construction of the discus circle.
The discus must land so that the point of impact is within the inner edges of lines marking the sector. It does not matter where the discus goes after the first impact. The athlete must not leave the circle until the discus has landed. The athlete must leave the circle from a standing position.
The trial is measured from the closest mark made by the discus to the inner edge of he steel band along an imaginary line drawn through the centre of the circle.
All measurements must be made immediately after each trial.
Measurements are made to the nearest centimetre below the distance thrown.