Tendonitis is pain in or around a tendon, which is a band of strong tissue that connects a muscle to a bone. Tendons bend, stretch, and twist to help joints and muscles move. They can become inflamed ...
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Patellar tendonitis or jumper's knee

Medically reviewed by Amy Kwan, PT Key Takeaways Patellar tendonitis happens when the tendon becomes inflamed and irritated.