expression, suru verb (irregular)
walk one's legs off; walk until one's legs feel like lead; walk to the point of exhaustion
Idiomatic expression describing extreme fatigue in the legs from walking a long distance. Often used in the form 足を棒にして.
一日中観光して足を棒にした。
I walked my legs off sightseeing all day.
He finally reached his destination after walking until his legs felt like lead.