Runner’s Knee Explained: Symptoms, Causes, And Treatment

Runner’s knee is one of those nagging injuries most runners have heard of—or worse, experienced firsthand–I sure have. It can throw a serious wrench in your training, sometimes even forcing you to hit pause completely during your training cycle.

Runner’s knee is an umbrella term that describes several conditions that cause pain around the patellar tendon. The sports medicine term is referred to as Patellofemoral Pain Syndrome (PFPS).

It is often dubbed ‘Runner’s Knee’ due to its incidence in the running community. Studies have shown¹Bump, J. M., & Lewis, L. (2023, February 13). Patellofemoral Syndrome. Nih.gov; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK557657/ prevalence ranges from about 19–30% in female runners and 13–25% in male runners. PFPS can be a nuisance to treat, and according to healthcare providers, it may reoccur after two years in 40% of cases.²Winters, M., Holden, S., Lura, C. B., Welton, N. J., Caldwell, D. M., Vicenzino, B. T., Weir, A., & Rathleff, M. S. (2020). Comparative effectiveness of treatments for patellofemoral pain: a living systematic review with network meta-analysis. British Journal of Sports Medicine, 55, bjsports-2020-102819. https://doi.org/10.1136/bjsports-2020-102819

‌Dealing with runner’s knee can be frustrating, but with the right approach, it doesn’t have to derail your running for long. This guide provides the latest science on patellofemoral pain syndrome (PFPS) to help you understand the causes, recognize symptoms early, and follow a solid rehab plan—including targeted exercises.

Listen to your body, prioritize recovery, and you’ll be back to pain-free miles in no time.

What Is Runner’s Knee?

Runner’s knee is often characterized by a gradual onset of dull to moderate pain at the front of the knee, especially during physical activity. However, it can also appear around or on the backside of the knee.

As the name suggests, running is often a primary cause of injury. However, any activity that repeatedly loads the soft tissues of the patellofemoral joint while the knee is flexed can cause the injury.  

How To Diagnosis PFPS

One of the key signs of PFPS is knee pain when your muscles are working against resistance—like when you bend down or squat. In fact, about 80% of people with PFPS feel pain in the front of the knee during squats.³Cook, C., Hegedus, E., Hawkins, R., Scovell, F., & Wyland, D. (2010). Diagnostic Accuracy and Association to Disability of Clinical Test Findings Associated with Patellofemoral Pain Syndrome. Physiotherapy Canada, 62(1), 17–24. https://doi.org/10.3138/physio.62.1.17

‌To diagnose it properly, doctors need to rule out other knee issues like IT band syndrome, patellar tendonitis, or chondromalacia since each one requires a different approach to rehab.

If you’re dealing with knee pain, don’t try to tough it out—see a qualified healthcare professional to get the right diagnosis and treatment plan!

What Are The Causes?

Runner’s knee doesn’t have just one cause. It can be triggered by weak muscles, poor alignment, biomechanics, or even your training habits. All of these factors can increase your risk of developing pain.

Determining the root cause of PFPS is key to effectively treating it.

Here we will look at a few of the most common culprits:

Muscle And Joint Weakness

Weak muscles surrounding the knee can jeopardize the stability and tracking of the patella within the patellofemoral joint.

The thigh muscles, including the quadriceps and the hamstrings, and the hip muscles all play a part.

This can cause the kneecap to move out of its normal path while running, putting extra pressure and stress on the joint which can lead to patellofemoral pain.⁴Lack, S., Neal, B., De Oliveira Silva, D., & Barton, C. (2018). How to manage patellofemoral pain – Understanding the multifactorial nature and treatment options. Physical Therapy in Sport, 32, 155–166. https://doi.org/10.1016/j.ptsp.2018.04.010

Patella tracking disorder is when the patella does not move properly within the femoral groove.

#1: Quadriceps

The quadriceps are primarily responsible for stabilizing the knee joint.

Specifically, knee stability mainly occurs via the vastus lateralis muscle and the vastus medialis muscle (lateral and medial quadriceps).

Suppose the lateral thigh is excessively tight and the medial thigh weak. In that case, the femur is more likely to rotate in, causing the patella to strike the edge of the femoral groove, leading to extra pressure and subsequent pain.

#2: Hamstrings

The hamstrings are crucial for your stride when running. They help extend the hip and control the movement of the tibia, minimizing knee flexion near the end of the swing phase.

If overly tight with a limited range of motion, the hamstrings may pull the tibia posteriorly. This puts more posterior force on the knee, increasing pressure between the patella and the femur.

#3: Hips and Illiotibial Band

A tight iliotibial band may lead to excess lateral force on the patella.

It may also lead to external rotation of the tibia, which could affect tracking.

Weak hip muscles can cause your foot to roll inward (pronation) as a way to compensate, which can affect your running form and lead to pain or injury.

#4: Calves and Feet

Foot pronation, commonly known as having flat feet, causes a compensatory internal rotation of the tibia or femur that may aggravate the patellofemoral joint.

Foot supination (foot rolls outwards) provides less impact absorption for the leg when it strikes the ground, so more stress is placed on the patellofemoral joint.

Training Methods

Overuse is the most common cause of injury. This is true for almost all running injuries.

Overuse is different for every runner—it all comes down to how much stress your body takes on and how well you recover from it.

To gauge whether you are overdoing it, here are a few things to consider:

• Have I recently increased my running volume? If you are new to running, increase your volume slowly. Allow your body time to strengthen. If you have been running consistently, check for recent inconsistencies or spikes in your training.

• Have I recently increased my running intensity? Increasing intensity will likely increase the force experienced by the knee when running.

• Have I changed my running environment? If you have recently incorporated downhill running, you will likely be placing extra stress on the PF joint.

• How is my sleep? Try and get 7-9 hours of sleep per night; it works wonders. Aim to wake up feeling rested.

• Have I introduced something new? Decided to do some strength and conditioning work at the gym? Great job. But allow yourself adequate adaptation time.

Can You Run With Runner’s Knee?

As previously mentioned, you best check with a medical professional before heading out on your next run. They will be best set to consider your case and make recommendations accordingly.

Whether you can run will depend on what caused the injury in the first place.

Was it muscle imbalance or weakness?

Strengthening the muscles and tendons with a progressive overload program of strengthening exercises takes a long time. If you continue running, you may exacerbate weaknesses that are already causing trouble.

Did overuse cause the injury?

If it were caused by overuse, the prognosis would largely depend upon how much inflammation there is in the area.

If the pain is acute, intense, and present often, it is best advised to rest. If you continue to run despite this pain level, you will worsen it.

If your pain level exceeds a 3 out of 10, it’s wise to stop running and try low-impact cross-training or rest until the pain has decreased. 

If the pain is very mild and goes shortly after exercise, you may be able to continue running. However, you should reduce your running volume and intensity.

9 Exercises For Runner’s Knee

PFPS should be detected, managed, and treated early. Alongside physical therapy, shoe inserts or orthotics, taping, and anti-inflammatory medication such as ibuprofen and naproxen, long-term strengthening is crucial for pain relief and avoiding re-injury

A progressive overload program should focus on strengthening the quadriceps, hip rotation, and abduction. A good warm-up, mobility work, and isometric exercises will be particularly useful early on.

What level of exercise difficulty you choose will depend on the severity of your injury. You should make progress through the exercises when they become easy. If one hurts, stop doing it, make it easier and try again.

Phase one of exercise rehabilitation:

Phase one will feature low-load muscular activation exercises and stretches.

#1: Hamstring stretch

1. Lay on your back with a band wrapped around the foot, and secure the other end in your hands.
2. Keeping your leg straight, pull your leg upward, stretching your hamstrings.
3. Hold and slowly return.

3 sets, of 20 seconds.

#2: Fire Hydrant

1. Begin on all fours.
2. Engaging your thigh and glute, lift one knee out and keep your knee bent at a 90-degree angle.  
3. Lower your leg and repeat on the other side.

3 sets of 15 repetitions.

#3: Side Plank

1. Lie on your side with your legs straight and feet stacked. Keep your elbow under your shoulder with the forearm pointing away.
2. Engage the core and lift your hips off the mat. Your body should be straight from your ankles to your head.
3. Hold this position and then lower back down.

3 sets, 30-60 second hold.

Phase two of exercise rehabilitation:

Phase two will slowly increase the load experienced by the knee, focusing on multi-chained control and coordination exercises.

#1: Squat

1. Pop the resistance band just above your knees.
2. With feet slightly wider than hips and your feet are turned out 5 – 10 degrees, lower yourself down and push your hips back. Keep your knees pushing out sideways into the band.
3. Stand up and repeat.

3 sets, 12 repetitions.

#2: Step Up

1. Step up with your left foot, pressing through the heel to straighten your left leg.
2. Bring the right foot up.
3. Bend in the knee and step your right foot back down.
4. Repeat.

3 sets of 2 minutes intervals

#3: Walking Lunge

1. Stand upright and tall, core engaged, your shoulders back and chin lifted.
2. Take a long step forward with your right foot, allowing your left heel to lift naturally as you step forward.
3. Allow your back knee to lower toward the floor. Stop just before it touches down.
4. Press firmly through your right heel, lifting your left leg as you stand.

4 sets, 10 repititons

Phase three of exercise rehabilitation:

Plyometric work, incorporating bilateral work with heavy but controlled impact to mimic some of the force endured when running. Progressing to single-legged work.

#1: Box Jump

1. Stand facing the box, feet hip-width apart.
2. Bend your knees and press your hips back, jumping off the balls of your feet.
3. Land with both feet on at the same time on the box, allowing your knees and hips to bend to help absorb the force of the landing.

4 sets, 10 repetitions

#2: Squat Jump

1. Stand with your feet shoulder-width apart and the toes pointing slightly outward.
2. Bend your knees lower your hips back, push through the heels, and jump straight up.
3. Land with your knees slightly bent and went back into the squat position.

3 sets, 15 repititons

#3: Single-legged Squat

1. Start by standing on one leg. Lift your opposite leg and hold it straight and slightly before you. For balance, your arms can be by your side or out in front of you.
2. Engage the core, keeping your torso relatively upright throughout the movement. Start to lower your hips back into a squat position. Aim to get low enough that your hips are parallel to the ground.
3. Squeeze your glutes as you push into the planted foot to stand back up. Try to keep your straightened leg up between repetitions

3 sets, 10 repetitions

Recovering from runner’s knee might feel like a long road, but with the right approach, you’ll be back to logging pain-free miles before you know it.

By understanding the causes, recognizing symptoms early, and committing to smart rehab—like strengthening exercises and proper recovery—you can prevent this nagging injury from sidelining you for good.

Remember, running is a lifelong journey, and setbacks like PFPS are just bumps in the road. Stay patient, listen to your body, and trust the process.

Check out this next strength training workout to ensure you keep your body in tip top shape for training:

Our Complete Strength Training Plan For Runners

References

• 1
  Bump, J. M., & Lewis, L. (2023, February 13). Patellofemoral Syndrome. Nih.gov; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK557657/
• 2
  Winters, M., Holden, S., Lura, C. B., Welton, N. J., Caldwell, D. M., Vicenzino, B. T., Weir, A., & Rathleff, M. S. (2020). Comparative effectiveness of treatments for patellofemoral pain: a living systematic review with network meta-analysis. British Journal of Sports Medicine, 55, bjsports-2020-102819. https://doi.org/10.1136/bjsports-2020-102819
• 3
  Cook, C., Hegedus, E., Hawkins, R., Scovell, F., & Wyland, D. (2010). Diagnostic Accuracy and Association to Disability of Clinical Test Findings Associated with Patellofemoral Pain Syndrome. Physiotherapy Canada, 62(1), 17–24. https://doi.org/10.3138/physio.62.1.17
• 4
  Lack, S., Neal, B., De Oliveira Silva, D., & Barton, C. (2018). How to manage patellofemoral pain – Understanding the multifactorial nature and treatment options. Physical Therapy in Sport, 32, 155–166. https://doi.org/10.1016/j.ptsp.2018.04.010