lab hesitant on tile / laminate floor

Question
My male chocolate lab about 18 months old in the past week became hesitant on my linolium and laminate flooring. He walks close to the walk with his hind legs slightly bent as if he is afraid of something. When we go upstairs to the bed room at the top of the stairs on the landing he stops and hesitates to come into the room as if he is afraid to come forward. If he is nugded he will go. He runs around the rest of the house and outside fine.

Thoughts?

Answer
He has been around it all along?  He may have had a misadventure, slipping falling.  If he doesn't return to normal in a few more days, perhaps see the vet.  Paws work better on carpet and natural surfaces.  The dog guide school we raise puppies for explicitly asks us to expose the puppies to slippery floors.  Otherwise, a dog might have problems out in public.