Why do my knees hurt when I jump?

Jumping knee pain often reflects doing too much volume too soon, quadriceps and patellar tendon that are not yet prepared for the load, poor landing mechanics, or limited ankle mobility forcing the knee to absorb more. Reduce volume, improve landing technique, and build tendon capacity gradually. Persistent or sharp pain needs a clinician.

The usual contributors

• Load spikes: A sudden increase in jumping volume is the single most common trigger. Tendons adapt more slowly than muscle and dislike rapid change.
• Landing mechanics: Stiff, upright landings with little hip and ankle contribution push force into the knee. Knees collapsing inward add to it.
• Limited ankle dorsiflexion: If the shin cannot travel forward, the knee absorbs a larger share of the landing.
• Weak posterior chain: When the hips do not contribute to absorbing force, the quadriceps and patellar tendon take it instead.
• Surface and footwear: Hard surfaces and worn shoes both raise the load per contact.

What to change first

Cut jumping volume to a level that does not provoke symptoms rather than stopping entirely, since complete rest tends to leave tendons less prepared than before. Then rebuild slowly, adding roughly 10 to 20 percent of contacts per week.

Build the tissue's capacity

Slow, heavy quadriceps work is well supported for patellar tendon problems. Use split squats, leg presses, and slow-tempo squats with a three-second lowering phase. Add Romanian deadlifts and glute bridges so the hips take their share, and improve dorsiflexion with ankle mobilisations.

Fix the landing

Practise quiet landings from a low box: Absorb through the ankles, knees, and hips together, keep the knees tracking over the toes, and hold the position for two seconds. Noise is a useful proxy for force absorption. More detail is in Landing Mechanics and Force Absorption.

When to see someone

Sharp pain, swelling, giving way, locking, pain that persists for weeks despite reduced load, or pain that is worse the morning after all warrant assessment by a physiotherapist or doctor. Knee pain in growing adolescents is common but should also be checked rather than trained through.