Jumper's knee: what patellar tendinopathy is, and how to load it

This one is about braking, not jumping. The step where you stop hard for a wide ball is the biggest load this tendon takes in tennis, and it is the thing you quietly start avoiding — usually before you notice you are doing it. Rest makes the knee comfortable and leaves it no better at braking. What rebuilds it is slow heavy loading through range, then the spring put back deliberately, in that order.

What it actually is

Jumper's knee is a problem with the patellar tendon, which runs from the bottom of the kneecap to the top of the shin. It is a classic energy-storage tendon injury: it complains about jumping, landing and changing direction rather than about steady running. The pain is usually very localised — most people can put one finger on the exact spot, which is one of the more reliable features of this particular problem.

Who gets it, and what it feels like

Jumping and cutting athletes above all — basketball, volleyball, tennis, padel. It often appears after a jump in training volume, a surface change, or a return from a break. Early on it warms up during activity and hurts afterwards, which is exactly why it gets ignored for months.

What sets it off

The movements people most often report as the trigger, in roughly the order they come up:

• Landing
• Lunging for a wide ball
• Squatting
• Stairs, especially down
• Sprinting and stopping
• Changing direction

When it is not this

Everything above assumes a tendon that is overloaded rather than something else wearing the same costume. These are the patterns that do not behave like a tendon problem, and any one of them is a reason to be assessed in person before loading anything:

• You cannot straighten the leg or lift it straight off the bed, or the kneecap sits oddly high. That is the picture of a ruptured patellar or quadriceps tendon rather than an irritated one. It is a surgical problem and a same-week one, not something to load.
• The knee swells up inside the joint after activity, or it feels tight and full. Tendinopathy does not fill the joint with fluid. Swelling inside the knee points at the cartilage, the meniscus or the joint lining, which need looking at rather than loading.
• The knee locks, catches, or gives way underneath you. Mechanical symptoms point at something inside the joint — a meniscus or a ligament — and no amount of tendon loading will change them.
• The ache is around or behind the kneecap rather than a sore point just below it, and sitting still makes it worse. That pattern is patellofemoral pain, not patellar tendinopathy. The two need almost opposite programs — deep loaded knee bends help one and aggravate the other — so it is worth having someone point at the right spot before you start.
• Numbness, tingling, or pins and needles down the leg. Tendons do not cause numbness. Symptoms down the leg point at a nerve, often referred from the back, and need a different assessment.
• It started suddenly — a fall, a knock, or a pop you felt. A sudden mechanical onset suggests something tore or broke rather than gradually overloaded, and that has to be examined before it is loaded. This is the difference between a tendon that is irritable and a tendon that is no longer attached.
• Visible deformity, significant swelling, or heat around the joint. Swelling and heat are not typical of tendinopathy, and can indicate infection or an inflammatory joint problem.
• Unrelenting pain at night that wakes you and will not settle. Pain that does not ease with rest or position does not follow the tendon pattern and warrants a proper look.

Why resting it does not work

Rest reliably reduces pain, which is why it feels like the answer. The problem is what it does to capacity: a tendon that is not loaded gets weaker, and the muscle around it gets weaker faster. So the pain settles, you return to what you were doing, and the tendon now has even less tolerance than it had when it first complained. That is the cycle most people are in by the time they start looking things up.

What tendons respond to is load — applied heavily enough to be a stimulus, slowly enough to be controlled, and progressed only when the previous step has settled. That last part is the whole game, and it is where most self-directed attempts come apart.

What a proper progression looks like

Four phases. The order is not arbitrary: each one is only useful once the one before it has stopped being provocative.

The minimum time across those phases is around 8 weeks, and that is a floor rather than an estimate. Tendons need elapsed time as well as clean sessions, which is why a program that lets you skip ahead on enthusiasm is not doing you a favour.

The exercises

These are the movements the progression is built from. The cue matters more than the name — tempo is most of the stimulus in tendon work, and doing these fast turns them into something else entirely.

How much pain is acceptable

Up to about 5 out of 10 during loading is acceptable and expected. The number that actually decides whether a session was a good one is the next morning: if it has settled back to your normal baseline, that session was fine regardless of how it felt at the time. If it has not, that was too much — whatever the pain score said during it.

This is the rule most people get wrong in both directions. Some stop at any discomfort and never load enough to change anything; others push through a 9 and wonder why it is worse a fortnight later.

When to see someone

If any of the patterns in the section above apply, if it is getting worse rather than settling, or if it simply is not matching what is described here, see a physiotherapist or doctor. This page is general education about a common problem; it is not an assessment of yours, and it cannot be.