You're probably referring to The Odyssey 4:199-202, which reads:

καὶ γὰρ ἐμὸς τέθνηκεν ἀδελφεός, οὔ τι κάκιστος

Ἀργείων: μέλλεις δὲ σὺ ἴδμεναι: οὐ γὰρ ἐγώ γε

ἤντησ ̓ οὐδὲ ἴδον: περὶ δ ̓ ἄλλων φασὶ γενέσθαι

Ἀντίλοχον, πέρι μὲν θείειν ταχὺν ἠδὲ μαχητήν.

The text doesn't mention a rank called "runner", nor does it imply a usefulness in war. The last line simply says that Antilohos was "not only quick, but also a fighter". In the context, the word "μαχητήν" (which translates to fighter) refers more to a person's strength, bravery, courage, etc. (Kinda like how we'd say today: "Ah, that John, he's a fighter!") In most Greek translations, they use the word "ανδρείος" to translate that part, which translates to "valiant". So, since strength and agility usually don't go together, I assume the praise here is that this man had managed to conquer both domains of athleticism, meaning that he was both fast and strong.

In case you find this odd, note that the most important sports of the time were running, weight-lifting, and wrestling. Also, think about people like Bruce Lee. He was famed for being not only strong, but also fast.