Mom had HORRIBLE arthritis. By the time she'd wake up of a morning she could barely move her arms. After struggling to get dressed she'd go outside and walk up and down the road swinging her arms with each step. Tears would be rolling down her cheeks because of the pain. When I asked her why she did it when it hurt so much she said that if she didn't she'd get to where she couldn't move her shoulders at all.
Now that I'm 57 I understand exactly what she was talking about. I have a house with a lot of stairs that I climb up and down daily. Sometimes it takes longer than other times but it's still necessary.