d5aa8617_University_of_Chicago_Medicine__Possible_cause
[Type of overuse injury] Jumper's knee (patellar tendonitis) [Symptoms] Tenderness right below the knee or the upper shin area [Possible cause] 
The patellar tendon in the knee joint is repeatedly pulled on, causing inflammation and pain, especially during jumping activities.
Overuse Injuries - The University of Chicago Medicine
Possible cause