This is the 9610th most frequent Japanese word.
老骨
"Old bones" - refers to the elderly or aging body.
Here, 老骨 metaphorically refers to the speaker's own aged physical state or feeling the strain of hard work despite being aged.
老骨に鞭を打つような仕事を続けています。
I continue doing work that feels like whipping old bones.
In this sentence, 老骨 is used to humbly describe the speaker's old age while emphasizing their continued contributions.
この町の歴史を守るために、老骨ながら尽力してきました。
Despite being in old age, I have been dedicating efforts to preserve the town's history.
The term 老骨 is used here as a self-deprecating term to refer to oneself as a person of advanced age.