Runner’s Knee Explained: How To Diagnose and 9 Exercises To Treat It

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Runner’s knee is a condition you hear about regularly in the running world.

It can seriously hamper your training, leaving you completely sidelined.

Runner’s knee is an umbrella term that describes several conditions that cause pain around the patellar tendon. It is more accurately described as Patellofemoral Pain Syndrome (PFPS).

It is often dubbed ‘Runner’s Knee’ due to its high prevalence in runners. Studies have shown prevalence ranges from about 19–30% in female runners and 13–25% in male runners.

PFPS can be a nuisance to treat; PFPS may reoccur after two years in 40% of cases.

This article will provide you with up-to-date science regarding PFPS and get you back running!

In this article, we will be looking to answer the following:

  • What Is Runner’s Knee?
  • Runner’s Knee Diagnosis
  • Causes of Runner’s Knee
  • Symptoms of Runner’s Knee
  • Can You Run With Runner’s Knee?
  • 9 Exercises For Runner’s Knee

Let’s jump into it!

woman runner grasping her knee

What is runner’s knee?

Runner’s knee is often characterized by a gradual onset of dull to moderate pain experienced at the front of the knee. But can also appear around or on the backside of the patella.

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

Runner’s Knee Diagnosis

A standard diagnostic tool for PFPS is pain encountered during resisted muscle contraction of the knee.

You’ll likely experience anterior knee pain while squatting, which is present in 80% of those suffering from PFPS.

Diagnostic tests should involve the exclusion of other pathologies, such as Iliotibial band syndrome and patellar tendonitis, which have different rehabilitation protocols.

knee showing tendons bones and muscles

If you have an injury, be sure to go and see a qualified health professional.

Causes of Runner’s Knee

There is no single cause of runner’s knee, and muscle weakness, biomechanics, and training methods can all be involved.

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 quadriceps, hamstrings, and hips all play a part.

This can lead to altered patellar tracking while running, increasing the compressive and shearing forces experienced by the joint and thus can cause patellofemoral pain.

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, the hamstrings may pull the tibia posteriorly. They are placing more posterior force on the knee, causing pressure between the patella and the femur to increase.

Sore Hamstrings After Running 3

#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.

Additionally, dysfunction of the external rotators in the hip can result in compensatory foot pronation.

#4: Calves and Feet

Foot pronation (foot rolls inward) 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.

Runner's Knee Explained: How To Diagnose and 9 Exercises To Treat It 1

Training methods

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

Overuse is always relative to the runner in question. It depends upon the acquired stress and subsequent recovery.

To gauge whether you are over-doing 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.

Symptoms of Runner’s Knee

Here are the main symptoms of PFPS:

  • A dull ache or pain at or under the front or side of the kneecap,
  • Discomfort when bending the knee while weight-bearing,
  • Increased pain when walking up and down stairs or downhill,
  • Swelling around the knee,
  • Tenderness when palpating around the knee,
  • Crepitus (popping sound) or grinding feeling in the knee.
a knee being examined

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 takes time. If you continue running, you may exacerbate weaknesses 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, it would be advised that you reduce your running volume and intensity.

9 Exercises for runner’s knee

PFPS should be detected, managed, and treated early. Long-term strengthening is crucial for avoiding re-injury

A progressive overload program should focus on strengthening the quadriceps, hip rotation, and abduction. 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

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

fire hydrant stretch
  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

step up exercise

  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

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

Runner's Knee Explained: How To Diagnose and 9 Exercises To Treat It 2
  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

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

Photo of author
Ben is a qualified Personal Trainer and Sports Massage Therapist with a particular interest in running performance and injury. He has spent the last 9 years working with runners at his clinic in Brighton. Ben is a keen runner and avid cyclist. Evenly splitting his time between trail running, road biking, and MTB.

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