Philostratos (ca. 160 – nach 244 u.Z.), G Gymnasticus 7:

Hoplite races are ancient events, especially the one in Nemea, which they call the “armor race” as well as the “horse race” [οὓς ἐνόπλους τε καὶ ἱππίους ὀνομάζουσιν], and which is dedicated to Tydeus and the rest of the Seven. (1)

By contrast the Olympic hoplite race, according to the Eleans, was included for the following reason. The Eleans embarked on a war with the people of Dyme, a conflict so truceless that not even the Olympic festival brought any break in hostilities. When the Eleans were winning, on the day of the Olympic contests (2), a hoplite from the battle is said to have run into the stadium, bringing the good news of victory.

This explanation is plausible, but I have heard the same story from the Delphians, about the time when they were at war with some of the cities of Phocis and from the Argives, about the time when they were being worn down by constant warfare with the Spartans, and from the Corinthians, about a time when they were fighting both in the Peloponnese itself, and also beyond the boundaries of the Isthmus.

But my opinion about the hoplite race is different, for I agree that it was invented originally for military reasons, but I believe that it is included in the contests as a reminder of the resumption of warfare, and that the shield signifies that the truce is over and that weapons are necessary again. If you listen to the herald carefully, you will notice that he announces to the assembled people that the contest, the dispenser of prizes, is coming to an end, and that the trumpet is giving the signal of Enyalius (3), calling the young men to take up arms. This announcement also orders them to pick up the oil (4) and take it away, acting not as people who anoint themselves, but as people who have ceased to do so.

(Philostratus: Heroicus – Gymnasticus – Discourses 1 and 2. Ed. by Jeffrey Rusten & Jason König. Cambridge (Mass.)/London 2014, pp. 406-411)

(1) „Sieben gegen Theben“
(2) Ursprünglich fanden die Wettbewerbe in Olympia an einem einzigen Tage statt, während sie zur Zeit des Philostratos auf fünf Tage verteilt waren.
(3) d.h. Ares
(4) Dieses wurde nur zum Einreiben bei athletischen Wettbewerben benutzt.