I find that if I have a lazy weekend (2 to 4 days), no exercise and loads of sitting,  I will be quite stiff when I try to walk again. My right hip muscle (possibly the piriformis) will spasm a bit and I would stop walking for 3 seconds and continue again. Depending on how long I have been lazy, the more stops I would have. It usually goes away after the second day of walks but its annoying and a good reminder to be more active.

I also played tennis on the weekend for the first time. It was my biggest active day as I had walked 11.3 km with about 1km of jogging and then in the afternoon played a set of tennis. I had been looking forward to this and although a bit puffed, I managed to with 6-4 against a much younger opponent! I felt ok on the court, a bit nervous at first in chasing the drop shots but I found that I was able to do so without too much strain or pain.