Wikipedia: Delayed onset muscle soreness (DOMS), also called muscle fever, is the pain and stiffness felt in muscles several hours to days after unaccustomed or strenuous exercise. The soreness is felt most strongly 24 to 72 hours after the exercise. It is caused by eccentric exercise.
Me (groaning): oooh thats sore!
T: Take it easy, your body needs time to heal.
Me: No its not from the operation, its my thighs. God they’re killing me.
T: What were you doing yesterday? Did you go out?
Me: Err…. no. I did hang out the washing. And I washed the dishes in the kitchen.
T (sympathy rapidly evaporating): So you did a bit of housework?
Me: I cleaned the bathroom as well. It’s messed me up bad. I feel like I’ve run a marathon.
T: I’ve got a sore back from working on the boat…
Me: This housework stuff is dangerous. I’d best leave it another week.