The long jump is an athletics (track and field) event in which athletes combine speed, strength, and agility in an attempt to leap as far from the take-off point as possible. Competitors run down a runway (usually coated with the same rubberized surface as running tracks, crumb rubber also vulcanized rubber) and jump as far as they can from behind a foul line (commonly referred to as the "board", and usually defined by the trailing edge of a takeoff board embedded flush with the runway surface, or a painted mark on the runway) into a pit filled with finely ground gravel or sand. The distance traveled by a jumper is often referred to as the "mark" because it is the distance to the nearest mark made in the sand from the foul line. If the competitor starts the leap with any part of the foot past the foul line, the jump is declared illegal and no distance is recorded. At the elite level, a layer of plasticine is placed immediately after the board to detect this occurrence.