Question
Years ago I had developed knee tendonitis from a previous job that I did alot of driving.  Had a cortizone shot and have been pain free for awhile now.  About a year ago I started riding stationary bike 10 minutes a day and have been ok and then about 2 months ago I increased the bike to twice a day for 10 minutes and just last week the knee pain and stiffness has come back.  Should I stop the bike riding for awhile and start leg extensions to strengthen the quads and hope to help the knee or should I do extensions and still do the bike riding?  I also am wondering if any of the new supplements I started taking about the same time I had this knee pain start could cause it or is it just coincedence?  Started a calcium and magnesium supplement and also a B complex and changed multi vitamin to a better quality.  Can supplements affect the knee in that way?

Answer
Chances are the supplements are not causing the knee pain.  It sounds as if there is a return of your tendonitis.  I would try starting with extensions and hamstring curls to strengthen the knee.  If there is no change within a week, you may want to see a good chiropractor to have the inflammation issues addressed, as well as have any musculoskeletal problems corrected.