question: I do not have enough flexibility in my knee joint. The knee doesn t hurt but is stiff. I can only bring back my heel to about 90% closer to my buttocks. Many people can touch their heel to their buttocks. How can I figure out whether I have tendon or ligament problem with the patella, or the quad muscles, or the hamstring, or the calves. If I try to force my heel closer to my buttocks, a get a cramp n my hamstring muscle. If I do a little massage in the back of the knee joint it is a little painful. I How would you analyze my problem. -thanks