In a competition, the bar is initially set at a relatively low height, and is moved upward in set increments (usually 3 or 5 centimetres, can be 1 cm for record attempts). Each competitor has the option of choosing at which height they wish to start, but once a height has been cleared other competitors may not start at a lower height. Once a competitor has elected to begin, they can choose whether or not to attempt subsequent heights. A competitor may choose to pass at a given height or, after failing to clear the bar at a given height, may "pass" on subsequent attempts at that height. Any competitor who records three consecutive misses is out of the competition. The competitor who clears the highest jump is declared the winner. If two or more competitors clear the same maximum height, the competitor with the lowest number of failed attempts (at any height) wins. If that fails to break a tie for first place, a jump off is conducted. Heights obtained in such a jump off are eligible for records.
The modern high jump bar is made of glass-reinforced plastic or aluminium. Other materials are allowed, but there are weight and sag restrictions. The bar is approximately 4 metres in length (IAAF rules control length for record purposes), with a round, triangular, or square cross-section for most of its length, and two square resting points at each end. It is placed at a measured height on two uprights which allow the bar to rest on its ends at a measured height. Cleared heights are reported by measuring from the take-off point to the top edge of the lowest part of the bar. Directly behind the bar is a soft foam mat that allows for a safe landing. Competitors must leap off one foot to clear the bar. Although they may touch the bar in their clearance, the jump is ruled unsuccessful if the bar falls due to their touch. There are rare instances when competitors have been allowed to retry an attempt where the bar has fallen. This can only happen if the official declares that the bar fell due to other external circumstances, such as wind.
