Translation:My legs hurt after a long walk.
I gave a literal translation: "The legs hurt me after a long walk." It rejected it. I hate duolingo sometimes. I knew what it meant, but if I try to read into the meaning, sometimes it would punishthat instead. -_-
When talking about own body parts you can use either:
la kruroj = miaj kruroj
la okuloj = miaj okuloj