The first section of the psalm describes the psalmists sorry state, as God’s arrows, or chastisements rain down upon him. In verse 6 he says:
Miser factus sum, et curvátus sum usque in finem: * tota die contristátus ingrediébar.
The Douay-Rheims renders this as:
“I have become miserable, and am bowed down even to the end: I walked sorrowful all the day long”
Miser means wretched or miserable, so the first phrase is literally, I have been made wretched. The verb curvare means to bend, bow, or bow down, so the next phrase is I am bowed down. Usque ad finem ad finem literally means until the end, so can be interpreted as until death, however the neo-Vulgate follows St Jerome’s translation from the Hebrew in substituting ‘nimis’ here, so 'utterly bowed down' is probably the better rendering. The second half of the verse is more straightforward: it says I walked around (ingrediebar) all day (tota die) sorrowful (contritatus).
The link between mind and body
The searing descriptions of the psalmist’s plight in the first half of this psalm point to the importance of the connection between mind and body. These days it is fashionable to reject the importance of bodily gestures such as genuflecting, kneeling and custody of the eyes. Rather than being seen as tools to remind our minds of what we should be feeling and focusing on, they are often seen as signs of empty, even dangerous ritualism. Yet Scripture often reminds us, as this verse, that what we feel in our minds affects our bodies and vice versa.
If we feel true remorse for our sins then, we should indeed be literally bowed down, so ashamed that one can scarcely bare to lift up our eyes to heaven. St Robert Bellarmine comments:
“As regards the punishment, the passage may apply to that also; for the man guilty of sins of this class becomes "miserable, and is bowed down" very much, by remorse of con¬science, by fear of God's anger, and by the shame that so humbles and confounds him, that he has not the courage to raise his eyes to heaven. Both constructions of it can be united in this way. I am become miserable by reason of my sin, and the punishment consequent on it, and very much bowed down, because I have turned to carnal and groveling pleasure the face of that soul I should have fixed upon God; through shame, I dare not look up to heaven, and, thus humble and abject, I am forced to look upon the ground, and for all these reasons "I walked sorrowful all the day long," my conscience always reproving and accusing one; for what pleasure can the wretch feel once he becomes cognizant of his own wretchedness.”
In the context of Lent, the penitential psalms, for example are traditionally said kneeling (as are the prayers at each of the hours of the Office).
And more generally, St Benedict teaches his monks and nuns to maintain custody of the eyes using this verse in order to manifest outwardly his or her inner humility:
“…he should always have his head bowed and his eyes toward the ground. Feeling the guilt of his sins at every moment, he should consider himself already present at the dread Judgment and constantly say in his heart what the publican in the Gospel said with his eyes fixed on the earth: "Lord, I am a sinner and not worthy to lift up my eyes to heaven" (Luke 18:13; Matt. 8:8); and again with the Prophet: "I am bowed down and humbled everywhere".
You can find the next part on this psalm here.