AFTER YEARS OF PLAYING TENNIS UP TO 12 HOURS A WEEK...NYETTA NICHOL'S BODY IS FEELING THE STRAIN.

The elbow is a burning sensation. The knee is a whole other story. That is, once I can straighten it out and bring it back in that usually makes that pop sound and it feels fine again. I don't feel any pain.

AT 49, NYETTA IS LIKE OTHER LONG-TIME ATHLETES WHO COMPLAIN ABOUT AGING JOINTS.

ORTHOPAEDIC SURGEON NICHOLAS DINUBILE (PRONO: dee-newb-uh-lee) SAYS MUSCLE PAIN IS NORMAL AFTER A WORK OUT, BUT JOINT PAIN IS NOT.

If you have any swelling, bruising, any sudden pain, pain this is different on one side that the other, these are all important things to look for.

DINUBILE RECOMMENDS SEEING A SPECIALIST WHO CAN ACCURATELY DIAGNOSE AND TREAT THE PAIN THROUGH MEDICATION, PHYSICAL THERAPY OR EVEN SURGERY.

BUT HE ADVISES SOME AMATEUR ATHLETES GO ONE STEP FURTHER.

Sometimes your second opinion, instead of being an orthopaedic surgeon, should be a tennis pro and look at your technique which is a huge issue.

NYETTA IS ALREADY DOING JUST THAT AND SHE VOWS TO KEEP ON PLAYING IN SPITE OF THE PAIN.