Patellofemoral Pain Syndrome (Runner's Knee): Causes, Symptoms, and How to Fix It
Patellofemoral pain syndrome, better known as runner's knee, is pain around or under the kneecap that flares with running, squatting, stairs, and long periods of sitting. The good news is that it responds very well to physical therapy without surgery, mostly by rebuilding the hip and knee strength that controls how the kneecap tracks. It is one of the most common causes of knee pain, making up close to a quarter of all running injuries, and it affects women about twice as often as men. This guide covers what patellofemoral pain syndrome is, why it happens, the exercises that help most, and how to fix it for good.
What is patellofemoral pain syndrome (runner's knee)?
Runner's knee is an irritation of the tissue around the kneecap where it glides over the front of the femur. When the kneecap does not track smoothly through that groove, usually because the muscles that control it are not doing their job, the joint gets overloaded and irritated. It is called patellofemoral pain syndrome because the pain comes from the joint between the patella (kneecap) and the femur (thigh bone). Despite the name, you do not have to be a runner to get it. Anyone who loads the knee repeatedly, from lifters to hikers to people who sit at a desk all day, can develop it.
In my practice, the way I explain runner's knee to clients is simple: the pain comes from rubbing between the kneecap and the thigh bone. A muscular imbalance, whether that's tightness or weakness somewhere along the kinetic chain, usually at the hip or thigh, changes how the kneecap tracks and starts to create excess pressure behind the kneecap during loading activities. That pressure is what becomes knee pain. In my evaluation, we look for exactly which of those structures are impaired, so treatment targets the cause rather than just the sore spot.
Runner's knee symptoms
The most common runner's knee symptoms are a dull ache around or behind the kneecap, pain that worsens going up or especially down stairs, pain with squatting, lunging or kneeling, and aching after sitting with the knee bent for a long time. Some people notice a grinding, clicking or snapping feeling behind the kneecap. The pain usually builds gradually rather than starting from a single injury, and it tends to flare with running, especially downhill.
What causes runner's knee?
Runner's knee is caused by poor patellar tracking and overload, usually with a few contributors stacked together:
- Weak hip muscles. Especially the glutes and deep hip rotators. When they aren't strong enough to control the thigh, it collapses inward with every step and squat, dragging the kneecap off its track.
- Weak or imbalanced quads. The quads guide the kneecap through its groove, so when they're weak or one side pulls harder than the other, the kneecap glides unevenly and the joint takes the friction.
- A sudden spike in training volume. More mileage, more hills, heavier loads, or a fast return after time off. The knee can handle a lot, but it can't handle a lot all at once.
- Poor foot mechanics. Issues like overpronation change how force travels up the leg, and by the time that force reaches the knee, it's loading the kneecap at an angle it wasn't built for.
Underneath most cases is the same theme: the knee was asked to handle more than the surrounding muscles could control. It is the same overload story behind shin splints and other running injuries.
How physical therapy treats patellofemoral pain syndrome (runner's knee)
Fixing runner's knee means calming the irritated knee down while rebuilding the strength and control that keeps the kneecap tracking properly. That starts with manual therapy used to improve healing and decrease tissue guarding around the affected knee. This is accompanied by backing off the aggravating load and swapping in pain-free activity, then progressively strengthening the hips and knees. Research is clear on this: strengthening the hips and knees together works better than focusing on the knee alone, because a large part of the problem starts at the hip, not the kneecap itself. Cleaning up running form and footwear matters too. Most cases settle over several weeks to a couple of months when the plan targets the cause instead of just the sore spot.
In my practice, when a patient comes in with runner's knee, the first thing we check is functional movement and strength, because the two work hand in hand when dealing with patellofemoral pain syndrome. Something as simple as watching a step-down or a single-leg squat usually shows us whether the knee is collapsing inward and where the weakness is coming from. Based on the impairments and imbalances we find at the hip and knee, loading progression looks different for everyone, but it's built on a combination of manual therapy, functional strength training, progressive overload, and a structured return to sport.
Exercises for runner's knee
The best runner's knee exercises build the hip and knee control the kneecap depends on. In general they fall into a few buckets: hip and glute strengthening (side-lying leg raises, clamshells, hip abductor work, and step-downs) to stop the thigh from collapsing inward; quad strengthening in a pain-free range (isometric wall sits, controlled squats to a comfortable depth); and gradual loading built back up over time using progressive overload. Work in a pain-free range and build up slowly, rather than pushing through pain. These exercises vary per client, and the progression matters more than the list. Any movement that is right for one person's knee can flare another if the tissue is not ready for that load yet.
Manual therapy and dry needling for runner's knee
Alongside the strengthening, hands-on treatment helps calm an irritated knee and free up what is pulling on it. Manual therapy and joint mobilizations restore normal movement of the kneecap and the surrounding joints which allows you to complete the strengthening and stabilization exercises with less pain.
When the quad, IT band, and hip muscles stay tight and overworked, dry needling releases those trigger points, drives blood flow into the area, and calms the irritation, while cupping and scraping open up the tight tissue along the thigh and IT band. Dry-needling with electrical stimulation also helps to decrease localized inflammation around the knee and helps decrease pain receptor sensitivity, leading to less pain when bending and extending the knee. None of this replaces the strengthening. It gets you moving comfortably enough to load the knee properly, which is what fixes it long-term.
How to prevent runner's knee
Keeping runner's knee from coming back comes down to a few habits:
- Balance running and sports with strength work so the knee can handle the load.
- Build weekly mileage gradually, no more than about 10 percent at a time, and do not spike hills and volume in the same week.
- Keep up hip and glute strength year-round, not just when the knee hurts. It is the single most protective step.
- Pay attention to running form and replace shoes before they break down.
When to see a physical therapist for knee pain
See a physical therapist if the knee pain keeps coming back, limits running, stairs or other physical activity, does not improve after a few weeks, or comes with swelling, locking, or giving way. A good evaluation pinpoints exactly why the kneecap is being overloaded, so you are not guessing at generic exercises. A physical therapist can also rule out other potential knee problems that would require a different plan, and build the bridge for returning to running once the knee is ready.
How we treat runner's knee at Reclaim
At Reclaim Physical Therapy, we find the underlying reason why your kneecap is getting overloaded, calm the irritated tissue with hands-on work, and rebuild the hip and knee strength that keeps it tracking properly. As a concierge, in-home sports physical therapy practice serving Coral Gables and the surrounding area, the whole session comes to you, at home or wherever you train, one-on-one with a doctor of physical therapy.
Kneecap pain slowing you down?
Book an in-home visit with Reclaim Physical Therapy and we will find why your knee hurts and build a plan to fix it. Serving Coral Gables and nearby.
Frequently asked questions
What does runner's knee feel like?
A dull ache around or behind the kneecap that flares with stairs, squatting, running, especially downhill. Also, sitting with the knee bent for a while. Some people feel grinding behind the kneecap.
Can I keep running with runner's knee?
Often you can keep doing some activity, but cut back the running that provokes the pain and swap in pain-free cross-training while you rebuild strength. Pushing through worsening pain drags it out.
How long does runner's knee take to heal?
It varies with the cause and how early you address it. Normally, 6-12 weeks of consistent progressive overload will allow your muscles to act properly to decrease load on the kneecap.
Is runner's knee the same as patellofemoral pain syndrome?
Yes. "Runner's knee" is the everyday name for patellofemoral pain syndrome, pain from the joint between the kneecap and the thigh bone.