Commentary for Lamentations 5:13

Encumbered with millstones. When the enemies led them away in neck irons, they would place on their shoulders millstones and burdens in order to tire them.¹⁰Alternatively, ‘youths were forced to grind wheat,’ a task which drains their strength. (Ibn Ezra) And similarly, “[and boys] staggered with beams,” [meaning that] their strength failed. The expression of staggering כִּשְׁלוֹן applies to the weakening of strength, as is stated in Ezra, “And Yehudah said, ‘the strength of the bearer has failed,’”¹¹Nechemyah 4:4. and similarly, “He has caused my strength to fail.”¹²Eichah 1:14.