Patellar Tendinopathy (Jumper's Knee): What It Is, Why It Happens, and How to Fix It

If you've been dealing with knee pain just below the kneecap — especially pain that gets worse when you squat, jump, or go down stairs — you may be dealing with patellar tendinopathy. It's one of the most common tendon conditions I see, and it's also one of the most commonly mismanaged.

The standard advice tends to go something like this: rest it, ice it, stretch it, and hope for the best. When that doesn't work — and it rarely does long-term — people end up frustrated, confused, and often told there's nothing more to be done.

There is more to be done. The evidence on patellar tendinopathy has advanced considerably over the last 15 years, and what works looks quite different from what most people are told. Let me walk you through it.

What is patellar tendinopathy?

The patellar tendon connects your kneecap (patella) to your shin bone (tibia). Its job is to transmit the force generated by your quadriceps — the large muscles on the front of your thigh — into knee extension. Every time you squat, jump, kick, or climb stairs, your patellar tendon is doing significant work.

Patellar tendinopathy develops when the load placed on that tendon exceeds what it can currently tolerate, repeatedly and over time. The tendon doesn't tear or become inflamed in the way most people imagine. Instead, its internal structure — the collagen fibres and the matrix around them — begins to break down and reorganise in a less functional way. The tendon becomes thickened, disorganised at the cellular level, and painful.

You'll often hear this called "jumper's knee," and that name tells you something useful: it's especially common in people who do a lot of jumping, sprinting, or explosive lower body work. Basketball players, volleyball players, and track athletes are particularly affected. But you don't have to be an athlete. I've seen it in cyclists, in people who started a new gym routine too quickly, and in individuals who simply increased their walking significantly after years of relative inactivity.

"Patellar tendinopathy is a load management problem, not a structural injury waiting to be repaired. The tendon adapts to load — both too much of it and too little."

What causes it?

The underlying cause is almost always a mismatch between load and capacity. The tendon gets more stress than it can handle, and it doesn't get enough recovery time to adapt. This can happen gradually — through a slow accumulation of training volume — or suddenly, with a spike in activity.

Common triggers include: starting or significantly increasing a running or jumping program, returning to sport after time off, rapid weight gain (which increases load on the tendon), or switching training surfaces (harder surfaces increase impact load). Reduced quadriceps strength and poor hip control can also contribute — when the muscles around the knee aren't absorbing load effectively, more stress falls on the tendon.

What does the pain feel like?

Patellar tendinopathy pain has a fairly recognisable pattern. It tends to be localised — most people can point to it with one finger, right at the base of the kneecap or occasionally in the tendon below it. It's typically worse with loading activities and often eases with gentle warm-up (though it frequently returns after you stop). Morning stiffness is common. Deep aching at rest can occur in more irritable presentations.

One of the clinical features that distinguishes patellar tendinopathy from other knee problems is that it tends to be worsened by activities that load the quadriceps under tension — squatting, lunging, jumping, stairs — rather than by passive movements like bending the knee while sitting.

Why rest doesn't fix it

This is the part that frustrates most people when I explain it, because rest is almost universally the first thing recommended. And rest does reduce pain — temporarily. When you stop loading the tendon, you stop provoking it, and the pain decreases. But rest doesn't address the underlying problem.

A tendon that isn't being loaded loses capacity. Its collagen doesn't remodel, its stiffness decreases, and when you eventually return to activity, you're back at square one — or worse. This is why so many people with patellar tendinopathy go through cycles of resting, feeling better, returning to activity, and immediately flaring up again.

Recovery requires rebuilding the tendon's capacity through progressive loading, not protecting it from all stress.

What actually works: the evidence-based approach

The most well-supported treatment for patellar tendinopathy is progressive tendon loading — a structured, graduated program that starts at a level the tendon can tolerate and systematically increases over weeks and months.

The typical progression moves through four phases:

Phase 1 — Isometric loading. Holding a sustained contraction of the quadriceps without movement. The evidence suggests isometrics provide good pain relief and allow the tendon to experience load without the repetitive stress of dynamic movement. A wall sit held at 60° of knee flexion for 30–45 seconds is a common starting point.

Phase 2 — Heavy slow resistance training. This is the most important phase and the one with the strongest evidence. Slow, heavy squatting movements — typically at a 3-second-down, 3-second-up tempo — expose the tendon to the sustained mechanical stress it needs to remodel and strengthen. The load should be challenging. This is not a light rehab exercise; it's structured strength work.

Phase 3 — Energy storage (functional loading). Once the tendon has rebuilt baseline strength, we reintroduce faster, more dynamic movements that require the tendon to store and release energy — the function it will need for sport and daily life.

Phase 4 — Return to sport. Sport-specific loading, plyometrics, and gradual reintroduction of the activities that originally triggered the problem.

Shockwave therapy has emerging evidence as an adjunct for patellar tendinopathy, particularly for stubborn cases that haven't responded to loading alone. It doesn't replace the loading program — but it can help reduce pain enough to make loading more accessible.

Pain during rehab: what's acceptable

People are often concerned that any pain during exercise means they're causing damage. This is not the case. During tendon loading, some discomfort — up to about 4 out of 10 on a pain scale — is generally acceptable and expected. The tendon is being stressed as part of the remodelling process.

The monitoring tool I recommend is your pain level the next morning. If you wake up significantly stiffer or more painful than usual, the previous session was too much. If morning pain is the same or improved, you're within a tolerable range. Adjust from there.

What about injections, surgery, or bracing?

Cortisone injections are sometimes offered for patellar tendinopathy. The short-term evidence shows they can reduce pain, but multiple injections are associated with tendon weakening, and the long-term outcomes are not better than loading alone. I'd generally consider an injection only in cases where pain is so high that loading is impossible to initiate.

Surgery is rarely indicated and should only be considered after an extended, well-executed conservative program has genuinely failed.

Patellar tendon straps and bracing can provide short-term symptomatic relief and are sometimes useful as an adjunct during the loading program. They don't treat the tendon, but if they make loading more tolerable, they have a role.

The takeaway

Patellar tendinopathy is a frustrating condition that often lingers when it's managed with rest and passive treatments. But with a structured, progressive loading program, the prognosis is genuinely good — most people make a full recovery and return to the activities they want to do.

The key is understanding that you can't rest your way to a stronger tendon. You have to load it — carefully, progressively, and with patience.

If you're not sure where to start or you've been through the generic advice without results, I'd encourage you to take a more structured approach. My programs are built around exactly this evidence-based progression, and I offer virtual consultations for anyone who needs a more personalised plan.