The Runner’s Guide to Patellofemoral Pain Syndrome (Runner’s Knee)


Comprehensive Breakdown of Runner’s Knee

As one of the largest joints in the human body, the knee is a critical point of stress on the body, especially while running. In order to prevent painful injury and the loss of progress when training, it’s important to treat it properly. Failure to maintain knee health can result in patellofemoral pain syndrome, also known as runner’s knee. This guide will provide information on the nature of runner’s knee, degrees of severity, and ways to treat and prevent it.


Part 1: What is runner’s knee?

Runner’s knee, or patellofemoral pain syndrome, is a catch-all term for a variety of painful injuries that occur around the knee. The areas affected by runner’s knee are vast, since the knee is a very complicated joint in the body with many connecting tendons, tissues, and bones. Oftentimes, it is the tissue around the patella, or kneecap, that causes this injury. Runner’s knee can also afflict the tissue and tendons around the femur, or upper leg bone. This is where patellafemoral pain syndrome derives its name: from the patella and the femur.

Damage to the surrounding tissue will cause pain signals to be sent from the surrounding nerve endings to your brain. However, damage to the cartilage underneath the patella won’t always cause pain; in these cases, pain is only registered when inflammation occurs as a result of extended damage. For this reason, it’s possible to develop runner’s knee before pain even occurs, so it’s important to be aware of symptoms other than pain when making a diagnosis.

Causes of runner’s knee

Since patellofemoral pain syndrome is a catch-all disorder, there are many different potential causes for it to occur. The most common cause is general negligence, whether it’s poor running form, lack of proper rest, or inadequate running gear. However, runner’s knee can also be indicative of more serious health problems, so it’s important to rule out all possible causes before coming to this conclusion.

Something worth noting is that females are more likely  than males to develop runner’s knee. Numerous theories have been presented and debunked to explain this phenomenon, but the most likely reason why is due to differences in muscle definition, distribution of body fat, and hip movement.

Untrained leg muscles

A study conducted on runners and the cause of their knee-related injuries showed that poor definition in key leg muscles can cause patellofemoral pain syndrome. These muscle groups include the quadriceps and hamstrings, with improper levels of flexibility and overall strength contributing to knee pain and injury. Depending on levels of definition in these key muscle groups, the amount of weight loaded onto the knee joint or patella is affected, with too much pressure causing runner’s knee.

Unusually high activity

Another common cause for runner’s knee is engaging in a high level of activity very quickly, after a long period of inactivity. This is most commonly seen when adopting a high-intensity workout routine after a more sedentary lifestyle. Medical studies have shown this to be the case in up to 70% of all running related injuries, not just patellofemoral pain syndrome. Lack of proper stretching or other warm-up exercises can also contribute to injuries from high activity.

Worn cartilage

The meniscus is a piece of connecting cartilage located between the femur and tibia, or upper and lower leg bones. It is located underneath the patella, and extended stress or improper running methods can cause it to erode. When the meniscus is worn down to a certain point, pain can be felt in the kneecap of the affected leg. In cases like these, often surgery is required to repair the meniscus and stop the pain.

Step rate

A study conducted on high school track students discovered that one of the potential causes of patellofemoral pain syndrome is the rate of steps taken when running. After studying the students over an extended period, it was revealed that students that take fewer steps when running apply more pressure on each foot impact, which resulted in increased pressure on the patella. This increased pressure eventually led to misalignment, and subsequent pain.

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Flat feet

For runners with flatter arches, the force of impact when running can be disproportionately distributed to parts of the leg that can cause wear and pain over time. In addition to causing lower back pain, a medical study concluded that flat feet are more likely to cause patellofemoral pain than feet with higher arches. In this particular case, damage can be mitigated with the use of proper protective equipment such as arch-supporting insoles.

Degrees of severity for runner’s knee

Since patellofemoral pain syndrome encompasses many different possible afflictions and different areas of the knee, doctors have established different stages of runner’s knee. Divided into 4 grades, they are ordered from least severe to most severe, and different levels of pain and methods of treatment can result from each stage. Higher grades of runner’s knee will need more drastic treatment methods, and in some cases surgery is required.


Grade 1 
  • is the least severe stage, and it usually means some of the cartilage surrounding the knee has become softer.


Grade 2 
  • also involves the softening of cartilage, but also denotes additional wear and erosion of surrounding tissue.


Grade 3 
  • is where the softened cartilage starts to thin out, and the surrounding tissue begins to deteriorate.


Grade 4
  • is the most severe of patellofemoral conditions, where cartilage degradation gives way to bone exposure and direct contact with other bones.

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Part 2: How do you treat runner’s knee?

Once it has been established that the pain you are experiencing is a result of runner’s knee, treatment is the next step. There are a few methods runners can use to treat patellofemoral pain syndrome, varying in effectiveness and cost. A good starting point for treating runner’s knee, as is the case with many running injuries, is a period of extended rest. However, in situations where this isn’t possible, such as when training for an athletic competition, try some of these methods:


This is an important preventative measure for just about any running-related injury. However, there are specific stretches you can do to treat undue pressure or strain on the muscles and joints around your knee. There are many stretches that can be done without accessories, but some of the more powerful stretches may need extra materials. In general, it’s a good idea to invest in a resistance band, yoga mat, ball and/or step for these exercises.


In recent years, stretching as a vital part of a runner’s routine has fallen out of popularity. Some studies made into the validity of this practice concluded that it wasn’t very effective for treating injuries, and in some cases may even increase the risk of injury. These studies, while frequently quoted even to this day, had major flaws and inconsistencies in their data. A more rigorous study concluded that quad flexibility is very important to preventing runner’s knee, as well as other running injuries.


Stretches for treating runner’s knee:
Quad stretch:
  • Leaning against the wall at an arm’s length distance, grab your ankle and lift it against your butt. Hold for up to 30 seconds and repeat 3 times.
Hamstring stretch: 
  • Rest your heel on a 15″ high surface with your leg straight. Keeping your back straight, lean forward until you feel strain in your thigh. Hold for 30 seconds, repeat 3 times.
Calf stretch: 
  • Stand facing a wall, supporting yourself against it with both your arms fully extended. Bend one knee forward, close to the wall, and the other leg fully extended further away. Lean into the wall until pressure is felt in the extended leg. Hold for up to 30 seconds, repeat 3 times for each leg.
Leg lift: 
  • While lying on your side, tighten your thigh muscle and raise your leg in the air, lowering slowly. Do 2 sets of 15 or 3 sets of 10.
Leg raise: 
  • While lying on your back, bend one knee and rest your foot flat on the ground or mat. Tighten your thigh and lift your leg to 8″. Slowly lower back to starting position. 2 sets of 15, or 3 sets of 10.
Wall squat: 
  • Stand with your back against the wall, using a ball in between your back and the wall. Lower your body in a squat position until your legs reach a 45-degree angle. Hold for 10 seconds, then slowly raise back up. 2 sets of 15 or 3 sets of 10.
Resistance knee extension: 
  • Stretch a resistance band between your leg and a closed door. Facing toward the door, extend the leg attached to the resistance band to increase tension. Do 2 sets of 15, and repeat while turned to the side of the door and with your back to the door.
Step up: 
  • Place one leg on a step 3 to 5 inches off the ground, with your other leg flat on the ground. Shifting your weight to the elevated leg, straighten your leg while lifting the other leg off the ground. Slowly lower your leg back to the ground. Do 2 sets of 15 for each leg.

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Kinesio tape: 
  • Using kinesiology tape, or KT tape for short, many runners have managed to mitigate knee pressure and pain from runner’s knee. This practice is also backed by science, with a study conducted by China Medical University confirming that using KT tape can greatly reduce pain and improve stability in the knee when afflicted with patellofemoral pain syndrome. When applied around the knee, the mere presence of kinesio tape provides relief to the affected area, acting in a psychosomatic way as well.
  • The aid of orthotic products can greatly reduce problems brought about by runner’s knee. This includes insoles, compression sleeves or prescription orthotics from a podiatrist. In addition to being highly effective at treating patellofemoral pain syndrome, studies have shown that orthotic shoe inserts are highly effective at treating all manner of lower leg injuries from running: shin splints, plantar fasciitis, and Achilles tendonitis, among others. With these, runners can treat runner’s knee and even prevent it from cropping up again in the future.
  • This is obviously a worst-case scenario, but lower leg surgery is very effective if you’ve tried every other method with poor results. Often times, continued pain after trying these other methods most likely indicates severe damage, and a menisectomy may be required. Studies have been made comparing the effectiveness of surgery over standard exercise therapy, and there is a currently ongoing study further testing its effectiveness. Until further testing is finished, it is unclear if this is the most effective method of treatment, but current data makes it seem very likely that it is.


Part 3: How do you prevent runner’s knee?

Since patellofemoral pain syndrome is a very inconvenient injury, preventing further cases is just as important as treating onset cases of runner’s knee. For the sake of preserving hard work and training, and to prevent further deterioration of your legs, consider these methods. Keep in mind, some of them may require the use of additional materials, such as a treadmill, a step, a mat or a resistance band.


While it was invented as an aspect of ancient Indian spiritual practices, many athletes have adopted yoga for their own purposes. The relaxation and stress-reducing practices of this ancient art are easily translated to athletes and long-distance runners. In order to prevent wear and tear on any part of your body, regular stretching is very beneficial, and yoga involves some time-tested stretches that feel good and promote healthy living.

Yoga exercises to prevent runner’s knee:
  • Also referred to as Eka Pada Rajakapotasana, this is a hip opening exercise. From Downward Dog position, fold one leg so it rests under your stomach, with your toes pointing away from you. Stretch your other leg behind you, with your hands flat on the mat. Inhale and press into the mat, putting pressure on your spine.
Revolved Hand to Big Toe: 
  • The other name for this move is Parivrtta Hasta Padangusthasana. Lying on your back, bend one knee toward your chest. Fully extend the leg of your lifted knee into the air, forming a straight line, then cross it over your other leg. You may want to use a resistance band to aid you in this movement.
  • Also known as Parsvottanasana. Beginning in Mountain pose, move one foot behind you with the toes angled slightly outward. Square your hips and clasp your arms behind your back, grabbing your elbows. Bend your upper half at the hips, with your head over the leg in front of you.
Crescent Lunge: 
  • This exercise is also referred to as Anjaneyasana. Starting once again in Mountain pose, move one foot forward in a lunge, keeping your shin perpendicular to the floor. Put your hands together near your chest in a prayer-like position and twist from the waist, resting the opposite arm on the thigh of your forward facing leg. Hold for up to 30 seconds and then repeat with the other leg. This is great for your spine and lower back.
Half Monkey: 
  • A terrific stretch targeting the hamstrings, this is also called Ardha Hanumanasana. Spread your legs so that one is behind you and the other is outstretched in front. Make sure the back leg is bent, and your weight is distributed to your knee while your foot is flexed so that your toes are pointing away from your body. You can add a twist by rotating your upper body so that the opposite arm to your rear foot is outstretched in the air.


Strength Training

You may suspect that your case of patellofemoral pain syndrome was caused by exercising too much, or at too high a level of activity. In these cases, it’s important to gradually work your way up to higher activity levels, as your body needs some time to properly grow into these situations. This is the essence of physical training: slowly improving your abilities, with proper exercise and nutrition. Starting slow, and incorporating strength-building exercises in key areas, can be very effective in preventing runner’s knee.

Strengthening exercises for preventing runner’s knee:
  • While lying on your stomach, distribute your weight onto your toes and forearms. Form a straight line with your body, similar to a plank of wood, and hold for around 60 seconds. This will strengthen your abs and core.
Hip Hikes: 
  • With one foot on a step at least 4 inches off the ground, leave your other leg dangling free of the bench. Keeping both legs straight, lift the hip of your free leg upward, hold and slowly drop. Repeat with the other leg. Regularly performing this exercise will strengthen your glutes.
Resistance Leg Raises: 
  • Wrapping a resistance band between your legs, balance on one leg with your knees slightly bent. Lift the other leg forward, then to the side, then behind you, returning to the original position. Repeat with the other leg. This is another terrific exercise for your glutes and upper thighs.
  • While laying on your side, bend your knees to a 45 degree angle. Slowly lift your free knee into the air, pause and then lower back to starting position. Do this 10 to 15 times with each leg, and you will effectively strengthen your hips.
Back Extensions: 
  • Lie on your stomach, pressing your pelvis to the mat. With your hands behind your head, lift your entire upper half off the ground, bending at the back. Hold for five seconds and then slowly lower back to the ground. Repeat 10 times to strengthen your lower back.
  • Lying on your back, lift your hips off the ground and support your weight with your feet flat on the mat. Your body should be straight, except for your bent knees. Lift and extend one leg straight out, holding for five to ten seconds. Return to starting position and repeat seven to ten times for each leg. This will strengthen your core and glutes.


Gait Retraining

One of the most likely causes of runner’s knee, especially if it occurs to you multiple times, is your gait. The position of your feet and legs when making running strides is often the cause of debilitating injuries such as patellofemoral pain syndrome, as some studies have proven. Some of the damage caused by poor gait can be managed with the aid of orthotics, such as insoles for shoes. However, this is only a superficial solution for a much more serious issue, akin to putting a band-aid on a bullet hole. For this reason, engaging in some sort of gait retraining can go a long way towards preventing runner’s knee from happening again.


When it comes to runner’s knee, there are a lot of misconceptions masquerading as facts. It’s very important to locate the precise location and cause of any pain in your legs and knees if you want to fix the issue. For the most part, resting for a few days will cause minor cases of runner’s knee to subside. However, if you tried these techniques to prevent or treat patellofemoral pain syndrome and you still experience discomfort, contact a medical professional. With some forethought and training, you should be able to overcome this injury and continue training or simply running for fun.

Medical Sources

These are the sources cited throughout this article. Many of them are professionally published scientific studies, but this article shouldn’t be taken as scientific fact. With further research, some of these findings may be proven false, and the scientific community may change their positions on these issues. In any case, be sure to consult a doctor or other medical professional if you experience serious leg pain.


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