But, as it is in a nightmare, when sleep’s narcotic hand
Is leaden upon our eyes, we seem to be desperately trying
To run and run, but we cannot — for all our efforts, we sink down
Nerveless; our usual strength is just not there, and our tongue
Won’t work at all — we can’t utter a word or produce one sound ….

[Ac velut in somnis, oculos ubi languida pressit
nocte quies, nequiquam avidos extendere cursus
velle videmur et in mediis conatibus aegri
succidimus, non lingua valet, non corpore notae
sufficiunt vires, nec vox aut verba sequuntur ….]

Virgil (70-19 BC) Roman poet [b. Publius Vergilius Maro; also Vergil]

The Aeneid [Ænē̆is], Book 12, l. 908ff (12.908-912) (29-19 BC) [tr. Day-Lewis (1952)]
    (Source)

How Turnus feels, in the middle of combat with Aeneas, with the nightmarish crippling of his abilities by a Fury sent from Jove.

(Source (Latin)). Alternate translations:

As when in quiet night, sleepe seiles our eye,
In vain we seeme some earnest flight to trie,
But in the midst we faint, our voice doth faile,
Nor speech, nor words, nor our known strength prevaile.
[tr. Ogilby (1649)]

And as, when heavy sleep has clos'd the sight,
The sickly fancy labors in the night;
We seem to run; and, destitute of force,
Our sinking limbs forsake us in the course:
In vain we heave for breath; in vain we cry;
The nerves, unbrac'd, their usual strength deny;
And on the tongue the falt'ring accents die ....
[tr. Dryden (1697)]

And as in dreams by night, when languid sleep hath closed our eyes, we seem in vain to make effort to prolong a race on which we are intent, and in midst of our efforts sink down faint; nor power is in the tongue, nor in the body competency of wonted strength, nor voice nor words obey [the dictates of our will] ....
[tr. Davidson/Buckley (1854)]

E'en as in dreams, when on the eyes
The drowsy weight of slumber lies,
In vain to ply our limbs we think,
And in the helpless effort sink;
Tongue, sinews, all, their powers bely,
And voice and speech our call defy ....
[tr. Conington (1866)]

And as in dreams, when languid sleep at night
Weighs down the eyelids, and in vain we strive
To run, with speed that equals our desire.
But yield, disabled, midway in our course;
The tongue, and all the accustomed forces fail.
Nor voice nor words ensue ....
[tr. Cranch (1872)]

And as in sleep, when nightly rest weighs down our languorous eyes, we seem vainly to will to run eagerly on, and sink faint amidst our struggles; the tongue is powerless, the familiar strength fails the body, nor will words or utterance follow ....
[tr. Mackail (1885)]

E'en as in dreaming-tide of night, when sleep, the heavy thing,
Weighs on the eyes, and all for nought we seem so helpless -- fain
Of eager speed, and faint and fail amidmost of the strain;
The tongue avails not; all our limbs of their familiar skill
Are cheated; neither voice nor words may follow from our will ....
[tr. Morris (1900)]

As oft in dreams, when drowsy night doth load
The slumbering eyes, still eager, but in vain,
We strive to race along a lengthening road,
And faint and fall, amidmost of the strain;
The feeble limbs their wonted aid disdain,
Mute is the tongue, nor doth the voice obey,
Nor words find utterance ....
[tr. Taylor (1907), st. 118, l. 1054ff]

But as in dreams,
when helpless slumber binds the darkened eyes,
we seem with fond desire to tread in vain
along a lengthening road, yet faint and fall
when straining to the utmost, and the tongue
is palsied, and the body's wonted power
obeys not, and we have no speech or cry ....
[tr. Williams (1910)]

And as in dreams of night, when languorous sleep has weighed down our eyes, we seem to strive vainly to press on our eager course, and in mid effort sink helpless: our tongue lacks power, our wonted strength fails our limbs, nor voice nor words ensue ....
[tr. Fairclough (1918)]

As in our dreams at night-time,
When sleep weighs down our eyes, we seem to be running,
Or trying to run, and cannot, and we falter,
Sick in our failure, and the tongue is thick
And the words we try to utter come to nothing,
No voice, no speech ....
[tr. Humphries (1951)]

Just as in dreams of night, when languid rest
has closed our eyes, we seem in vain to wish
to press on down a path, but as we strain
we falter, weak; our tongues can say nothing,
the body loses its familiar force,
no voice, no word, can follow ....
[tr. Mandelbaum (1971), l. 1209ff]

Just as in dreams when the night-swoon of sleep
Weighs on our eyes, it seems we try in vain
To keep on running, try with all our might,
But in the midst of the effort faint and fail;
Our tongue is powerless, familiar strength
Will not hold up our body, not a sound
Or word will come ....
[tr. Fitzgerald (1981), l. 1232ff]

Just as when we are asleep, when in the weariness of night, rest lies heavy on our eyes, we dream we are trying desperately to run further and not succeeding, till we fall exhausted in the middle of our efforts; the tongue is useless; the strength we know we have, fails our body; we have no voice, no words to obey our will ....
[tr. West (1990)]

As in dreams when languid sleep weighs down our eyes at night,
we seem to try in vain to follow our eager path,
and collapse helpless in the midst of our efforts,
the tongue won’t work, the usual strength is lacking
from our limbs, and neither word nor voice will come ....
[tr. Kline (2002)]

In dreams,
When night's weariness weighs on our eyes,
We are desperate to run farther and farther
But collapse weakly in the middle of our efforts.
Our tongue doesn't work, our usual strength
Fails our body, and words will not come.
[tr. Lombardo (2005)]

Just as in dreams
when the nightly spell of sleep falls heavy on our eyes
and we seem entranced by longing to keep on racing on,
no use, in the midst of one last burst of speed
we sink down, consumed, our tongue won’t work,
and tried and true, the power that filled our body
fails -- we strain but the voice and words won’t follow.
[tr. Fagles (2006), l. 1053ff]