I know this because they hurt whenever I move, both of them.
Some people get biker legs, all buff and defined.
I get a little sore, but no buff or defined. On the other hand, I rode 40 miles today and it felt pretty good until the last 8 against the wind (okay, a minimalist breeze, but it felt almost like wind--perhaps because I was riding so very fast? Or because I'm a wimp).
I need to go out to the back yard and water some new plants. Unfortunately, that means either walking down (and then UP) the stairs, or walking outside and around, down the hill along one or the other side of the BardiacShack (tm). If I'm going to go down there, I should probably just go hog wild and do some weeding. At least I could sit on my rear (which isn't as sore as my legs, thank the good makers of the strategically designed bike saddle).