The first paragraph of this entry (with the arguable exception of 'The contests are 8 etc.') comes from the scholia to Aristophanes, Birds 292, where the accusative case of the headword occurs. See also delta 806.
[1] The diaulos, "two-pipe" or "two-channel" race, was added to the Olympic program in 724 BCE (Pausanias 5.8.4). The race consisted of two laps, each a stadion (c.600 ancient feet) in length. In Olympia, runners set out from the starting line at the west end of the course near the Altis, turned the post, kampter or terma, and returned to the starting line now serving as the finishing line. This view of the event is supported by Pausanias" comparison of the diaulos to letters written in boustrophedron on a cedar chest that he saw in the temple of Hera at Olympia: "from the end of the line, the second line turns back as runners do in the diaulos" (5.17.6).
The most pressing modern problem with the diaulos is how runners turned the post without colliding. Much is made of collisions at the terma in chariot-racing, but the sources are silent about similar disasters in the diaulos. Stephen G. Miller has suggested that each runner had two channels, one for the outward and another to its left for the inward run. Thus each runner turned a separate post. See Miller for discussion of this problem: "Turns and Lanes in the Ancient Stadium," American Journal of Archaeology 84 (1980) 159-166.
[2] The dolichos or long run was first held at the games of the fifteenth Olympiad, in 580 (Pausanias 5.8.6). All runners ran around the same posts, one at each end of the stadium. In the stadium at Nemea, the kamptêr at the south end was set off the central axis and away from the starting-line, as, presumably, was the one at the north end. This placement allowed the runner to avoid tripping on the raised starting-line. He could approach the post as closely as possible and then, as his momentum took him, swing wider to the left (Miller 1980.159). The number of laps varied from contest to contest within a range of seven to twenty-four stades.
[3] The hoplite race, added to the Olympic program for the sixty-fifth Olympiad (520) was a diaulos. During the classical period, runners carried a round shield, possibly covered with bronze (Pindar, Pythian Odes 9.1-4), and wore a helmet and shin guards. All ran in the nude, the custom for athletes in all contests except the horse races. Over time, the Eleans dropped the helmet and greaves from the race at Olympia (Pausanias 6.10.4). The hoplite race evokes the initial stage of battle when the hoplite ran to meet the enemy. Once the phalanxes collided, the fighter was rooted to his place in the line for the duration. Before then, however, he ran for some two hundred yards, exposed to the rain of enemy missiles, as fast as he could and still maintain formation, given the weight and constrictions of his panoply. Every hoplite surely prayed to get across that distance quickly and arrive at the enemy line with sufficient breath and energy to fight for his life. The race, it seems, recognizes this desire by celebrating swiftness of foot. Athletes in hoplite armor displayed the speed of the runner, mediating the unhampered speed of the naked runner who ran unencumbered by armor and the leaden discomfort of the hoplite traversing no-man's-land.
[4] The broad jump was not a separate contest but, with discus throw, javelin, stadion, and wrestling, formed the pentathlon.
[5] cf. delta 1336, delta 1338, delta 1339.