I find that if I'm in the car for anything more than about 20 mins, or I sit to long on the sofa, when I try and walk it's as if I suddenly have the legs of a 90 year old. The muscles feel stiff and tender and it takes about 10 mins of moving around to feel normal again. I try and walk for a least half an hour every day but it's not always possible. Will have to dug out the exercise DVDs now the weather has turned.