December 8, 2022

4 reasons why people get runner's knee (patellofemoral pain syndrome)

In this article you will find the 4 main reasons why people get runner's knee, which is also known as patellofemoral pain syndrome

Runner’s knee, also known as patellofemoral pain syndrome (PFPS), is a common injury among runners and other athletes. It is characterized by pain and discomfort around the knee, particularly when running or participating in activities that involve repetitive knee flexion and extension. Here are four reasons why people may develop runner’s knee and how physical therapy can help.

1) Overload

One common cause of runner’s knee is overloading the patellofemoral joint (PFJ), which is the joint between the kneecap (patella) and the thigh bone (femur). This can happen when a person increases their training intensity or duration too quickly, causing excessive stress on the PFJ.

To determine if overload is a factor, a physical therapist can quantify the recent increase in PFJ loading and recommend load management techniques as part of the therapy plan. You can check out knee-safe activites that Meghan Taff, our certified coach and PT, recommends.

2) Muscle performance deficits

Another reason for runner’s knee is weak or imbalanced muscles around the hip and quadriceps. This can lead to improper alignment and tracking of the kneecap, resulting in pain and discomfort.

To figure out if muscle performance deficits are a factor, a physical therapist can use tests such as the Hip Stability Isometric Test (HipSIT) and thigh strength testing. If muscle performance is an issue, the therapy plan should focus on exercises that target the posterolateral hip musculature and the knee, such as weight-bearing squats or resisted knee extensions.

3) Movement coordination deficits:

Poor movement coordination can also lead to runner’s knee.

This can be observed with functional movements such as gait analysis, squatting, and step-down testing. If movement coordination deficits are present, therapy should focus on gait retraining and movement re-education to improve alignment and reduce stress on the knee.

4) Mobility impairments

Finally, mobility impairments in the foot and hip can contribute to runner’s knee. For example, a person may have a hypermobile foot, which can lead to excessive foot pronation and increased stress on the knee. On the other hand, a person may have a hypomobile foot, which can cause the kneecap to be pulled laterally and result in pain.

To determine if mobility impairments are a factor, a physical therapist can use tests such as the patellar tilt test and muscle length testing. If mobility impairments are present, the therapy plan should focus on stretching or strengthening the affected structures.


Runner’s knee can be caused by a variety of factors, including overload, muscle performance deficits, movement coordination deficits, and mobility impairments. Physical therapy can help by identifying the underlying causes of runner’s knee and creating a personalized therapy plan to address them. By addressing these issues, physical therapy can help alleviate pain and improve function, allowing people to continue participating in the activities they enjoy. Still not sure if physical therapy is something for you? Read one of our blogs about 4 reasons to schedule physical therapy. If you need more info on runner's knee while training for a marathon you can read this blog about runner's knee on our website.

Written and edited by Netic Team

Authors: Louis Vanwalleghem MD, Meghan Taff PT, Susan Nowell PT

Louis Vanwalleghem: MD, PT

Meghan Taff: PT & USAT certified coach, ironman athlete & participated in over 100 races.

Susan Nowell: PT & coach, ironman athlete.

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