Patellar tendinitis is an injury to the tendon connecting your kneecap (patella) to your shinbone. The patellar tendon works with the muscles at the front of your thigh to extend your knee so you can kick, run and jump.
Patellar tendinitis, also known as jumper's knee, is most common in athletes whose sports involve frequent jumping — such as basketball and volleyball. However, even people who don't participate in jumping sports can get patellar tendinitis.
For most people, treatment of patellar tendinitis begins with physical therapy to stretch and strengthen the muscles around the knee.