Following a particularly tough off road distance race with lots of very steep ascents and descents I have developed a knee problem in one leg. It is not enough to stop me training but I am aware of a continual sore feeling under the knee cap as I run. If I sit with my leg nearly straight (foot on the floor forming an angle behind the leg of about 160 degrees) and probe around just below the knee cap (I believe there is a tendon in this area between knee and shin?) it feels quite tender, but if I then bend the leg to form a 90 degree angle and probe the same place again there is no problem.
I would be very grateful for any advice expert or anecdotal as I am worried that a more serious injury could be around the corner.