Patellar Tendonitis (Jumper's Knee): Symptoms, Causes and What Helps

If the spot just below your kneecap hurts when you jump, squat, run or walk down stairs, there is a good chance you are dealing with patellar tendonitis, better known as jumper's knee. Clinicians now usually call it patellar tendinopathy, because the problem is mostly about how the tendon handles load rather than classic inflammation.

What is the patellar tendon?

The patellar tendon connects the bottom of your kneecap to the top of your shin bone. Every time you land from a jump, push out of a squat or brake while running downhill, it stores and releases a lot of force. When the load on the tendon rises faster than it can adapt, it can become painful.

Patellar tendonitis symptoms

• Pain in a small spot right at the bottom of the kneecap.
• Pain that starts with loading: jumping, landing, squatting, lunging, stairs.
• Pain that eases as you warm up, then returns after activity or the next morning.
• Pain when you sit for a long time with your knees bent, in some people.

Swelling, locking, the knee giving way or pain after a twist are not typical of jumper's knee and are a reason to get your knee checked.

What causes jumper's knee?

The most common trigger is a quick change in load: a new season, extra jumping sessions, a switch to harder courts, more hills or a sudden jump in training volume. It is common in basketball, volleyball, running and court sports, and in people who suddenly add squats or stairs to their routine.

What helps patellar tendonitis

1. Manage the load, don't stop completely

Complete rest often makes a tendon weaker. Most plans reduce the activities that flare it (like high jumping volume) while keeping you moving. A simple rule many clinicians use: pain up to about 3 out of 10 during exercise is acceptable if it settles by the next morning.

2. Strengthen the tendon gradually

Exercise is the core of patellar tendinopathy treatment. Common stages are isometric holds (like wall sits) to calm pain, then slow heavy strength work (leg press, split squats), then a gradual return to jumping. Our free Knee Reset lays this out as a 14-day starter plan.

3. Use a patellar tendon strap for activity

A patellar tendon strap presses on the tendon just below the kneecap. In one study of young basketball and volleyball players with patellar tendinopathy, wearing a strap reduced pain in three of four jump tests without changing jump height. It is a support for training and sport, not a cure, so it works best alongside strengthening. Read more in Do patellar tendon straps work?

4. Look at your training plan

Build jumping and running volume gradually, spread hard sessions across the week and give the tendon time to adapt.

How long does jumper's knee take to heal?

Tendons adapt slowly. Mild cases can settle within a few weeks of sensible loading, while long-standing cases often take three months or more of consistent strengthening. Progress is rarely a straight line, so track your pain over weeks, not days.

When to see a professional

See a doctor or physical therapist if the pain is severe, came on suddenly with a pop, keeps you up at night, is getting worse despite sensible changes, or if you are not sure the pain is coming from the tendon.

Sources

• Malliaras P, Cook J, Purdam C, Rio E. Patellar tendinopathy: clinical diagnosis, load management, and advice for challenging case presentations. JOSPT, 2015.
• Dar G, Mei-Dan E. Immediate effect of infrapatellar strap on pain and jump height in patellar tendinopathy among young athletes. Prosthetics and Orthotics International, 2019.

This article is general information, not medical advice. If your knee is swollen, unstable, painful at rest or after an injury, or not improving, see a doctor or physical therapist.