The closest to personification that first jumps out to me in A.E. Houseman’s poem “To an Athlete Dying Young” is in the fourth stanza:
Eyes the shady night has shut
Cannot see the record cut,
And silence sounds no worse than cheers
After earth has stopped the ears
In this stanza, it’s possible to see “shady night” as being depicted as a person or something person-like. Here, night is not just something that happens in a regular, cyclical manner. Instead, in this poem, it is an active presence: it shuts the young athlete’s eyes.
The enotes study guide to this poem (see the link below) points to further possible instances of personification: “In the fifth quatrain, ‘renown’ and ‘name’ are personifications.” Rereading the poem with this in mind, I can see how the lines “Runners whom renown outran / And the name died before the man” can indeed be seen to contain personification. In the first case, “renown” is treated much like a runner in a race, and in the second case, “the name” is a mortal thing, like a person.
There are two particular passages Houseman uses personification in this poem.
In lines 13 and 14 "Eyes the shady night has shut/cannot see the records cut" Houseman personifies death giving it the ability to shut the young athletes eyes so that he may not see his records broken by another.
In line 10 "from fields where glory does not stay" he compares glory to a person who cannot stay in the field.