Should I start to exercise, thats my question. -- I have arthritis in both knees and suffered with severe pain mainly in my left knee. I had a DUROLANE injection a week ago and for the first time in ages I am pain free. I should try to exercise my legs to build up the muscle strength but I am worried, that if I do, , the pain will return and any benefit I have from the injection will be lost. Any advise would be appreciated.