Runner's Knee (Patellofemoral Pain)

What runner's knee is

The kneecap (patella) glides in a groove at the end of the thigh bone (femur) every time you bend and straighten the knee. Together they form the patellofemoral joint. When you run, squat or climb stairs, forces through this joint can reach several times body weight.

Runner's knee develops when that load exceeds what the joint and surrounding tissues can tolerate. The cartilage behind the kneecap is not usually damaged; instead, the bone under it, the fat pad and the joint lining become irritated and sensitive. For a full medical overview of the condition and its other causes, see patellofemoral pain syndrome. This page focuses on runners and getting back on the road.

Runner's knee symptoms

• Dull, aching pain around, behind or below the kneecap
• Pain during or after running, especially downhill or on stairs going down
• Pain when squatting, kneeling, jumping or getting up from a chair
• Pain after sitting for a long time with bent knees (the "movie-goer's" or theater sign)
• Grinding or clicking under the kneecap, usually harmless without pain
• Occasionally mild puffiness, but large swelling is unusual

Both knees are affected in up to half of people.

Causes and risk factors

Training errors (the main cause)

• Increasing weekly mileage too fast
• Adding hills, speed work or downhill running suddenly
• Too little recovery between sessions
• Sudden switch in shoes or surface

Body and movement factors

• Weak hip muscles, especially the gluteus medius, which lets the thigh drop inward and rotate as the foot lands
• Weak or tight quadriceps, and tight hamstrings or calves
• Overstriding with a heavy heel strike and a long stride
• Foot mechanics such as flat feet that roll inward excessively
• Kneecap alignment variations

Who is at risk

Women are about twice as likely as men to develop it. Teenagers, people new to running, and those returning after a break are also at higher risk.

Runner's knee vs other running knee pain

Diagnosis

A doctor or physical therapist will ask about your training, examine the knee, watch you squat or step down from a step, and test hip and thigh strength. Pain on a squat is one of the most consistent findings. Imaging is not needed for typical cases. X-rays or MRI are used if there was an injury, swelling, locking, or symptoms are not improving after a few months of good rehab.

Runner's knee treatment

1. Adjust the load, not total rest

• Cut weekly mileage, avoid hills and downhill running, and run on flat, softer surfaces
• Keep pain during activity at or below 3 out of 10, and settled by the next morning
• Cross-train with swimming, pool running or cycling with a raised seat
• Avoid deep squats and long sitting with bent knees for a few weeks

2. Strengthen hips and thighs

The 2019 clinical practice guideline recommends combined hip and knee exercises as the core treatment. Typical exercises, done 3 times a week:

• Side-lying leg raises and clamshells for the gluteus medius
• Glute bridges (single-leg as you progress)
• Banded side steps (monster walks)
• Wall sits or squats to a pain-free depth, increasing gradually
• Step-downs from a low step with the knee tracking over the second toe
• Straight-leg raises and leg presses for the quadriceps

Start with 2 to 3 sets of 10 to 15 repetitions and increase resistance over weeks.

3. Short-term relief

• Ice for 15 minutes after activity
• Acetaminophen (paracetamol) or an anti-inflammatory such as ibuprofen at the label dose, for a short period, if safe for you
• Patellar taping or a knee sleeve can reduce pain in the short term to allow exercise
• Foot orthoses help some people, especially those with flat feet, over the first 6 weeks

4. Running form changes

• Increase your step rate (cadence) by 5 to 10%, which shortens your stride and reduces knee load
• Land with your foot closer to under your body
• Consider gait analysis with a physical therapist

Injections and surgery are rarely needed and do not have good evidence for typical runner's knee.

Return to running

1. Start once walking, stairs and single-leg squats are close to pain-free.
2. Begin with walk-run intervals on flat ground, every other day.
3. Increase total weekly time or distance by about 10% per week.
4. Add hills and speed work last.
5. Keep doing strength work twice a week long term.

How long does runner's knee last?

Most people improve substantially in 6 to 12 weeks with a consistent program. Symptoms can linger or come back if training load rises too fast, and some people have recurring pain for years. Starting rehab early and continuing hip strengthening reduce recurrence.

Frequently asked questions

Can I run with runner's knee?

Often yes, at a reduced level. Run shorter and slower on flat ground, keeping pain at or below about 3 out of 10 during the run and back to baseline by the next day. If pain makes you limp or gets worse each run, stop and cross-train while you strengthen.

What is the fastest way to heal runner's knee?

Combine reduced running load with a daily or near-daily hip and quadriceps strengthening program. Short-term taping, ice and increasing your running cadence help. Complete rest alone is slower and less effective, because the muscles that protect the knee weaken further.

What are the best exercises for runner's knee?

Hip abductor exercises such as clamshells, side-lying leg raises and banded side steps, plus quadriceps exercises such as wall sits, step-downs and leg presses. Glute bridges help too. Combining hip and knee work gives better results than either alone.

Is runner's knee the same as patellofemoral pain syndrome?

Yes. Runner's knee is the common name for patellofemoral pain syndrome, which describes pain at the joint between the kneecap and thigh bone. It is also called anterior knee pain. It is not the same as chondromalacia patella, which refers to softening of the kneecap cartilage.

Should I wear a knee brace for runner's knee?

A knee sleeve or patellar strap may reduce pain for some runners, and taping has short-term benefit. They are aids, not cures. Strength exercises and training changes are what resolve runner's knee, so use braces only to help you stay active while you rehab.