Albert Barnes Commentary Lamentations 5:13

"The young men bare the mill; And the children stumbled under the wood." — Lamentations 5:13 (ASV)

They took the young men to grind - Or, “The young men” have worked at the mill, a menial and laborious task usually performed by slaves .

The children fell under the wood - Or, lads have stumbled under burdens of wood. 'Lads' here refers to youths up to the age of military service; another form of menial labor.