This injury includes chronic damage and inflammation in tendon fibers located at the bottom of your patella. Stress from the quadriceps muscle group is concentrated at this point. The most common cause of patellar tendonitis is repetitive micro-trauma to the tendon during activities which involve prolonged running or repetitive jumping.
Physical exam by a qualified physician is often sufficient to diagnose patellar tendonitis. In severe cases an MRI may be ordered to determine the extent of the inflammation and the health of the tendon.
Typical symptoms include pain at the bottom of your patella, which is made worse with activities such as running or jumping. In more severe cases, an area of swelling and tenderness is apparent. Weakness of the associated quadriceps muscle group is an unfavorable sign.
The cornerstone of prevention for any form of tendinitis is appropriate stretching. This should involve frequent low intensity, long duration stretching of the quadricep such as pulling your heel toward your buttock. At the first sign of pain with a given activity, modifications should be made in intensity or duration.