Recently I had to take a journey in a very cramped bus during which I was seated in one position for almost 6 - 7 hours with no opportunity to stretch my legs. After the journey my right knee has gone very stiff and I can feel that the muscles on the right side ie the outside of the knee have knotted up. As a result I am unable to bend my right knee. Any attempt to do so for more that 30 degree is very painful. However no such problems in my left knee. Previously Before this episode I had no problem sitting cross-legged in Sukhasana or even Padmasana. Please advise.