If you have joint problems, perhaps yoga could be a solution. A friend of us started taking yoga sessions and she doesn't only feel more relaxed, but she also feels that her body becomes more flexible. The first few sessions she had quite some pain afterwards, like muscle pain. But after that she feels better and better after every session and she can't stop telling everybody she knows. Including me, but I don't mind. I like listening to her when she is so enthousiastic about something. It shows that she truly likes it.