Runner’s Knee (Patellofemoral Stress)

Runner’s knee means that you have dull pain around the front of the knee (patella). This is where the knee connects with the lower end of the thighbone (femur).

Runner’s knee or Patellofemoral Stress is when the kneecap (patella) rubs roughly against the end of the thighbone (femur) when the knee moves.


Runner’s knee may be caused by a structural defect, such as a kneecap located too high or too low in the knee joint, off-centre insertion of the muscles into the kneecap, tight hamstrings, tight Achilles tendons, and weak thigh muscles – which normally help stabilize the knee. Weak thigh muscles are the most common treatable cause of the runner’s knee; these weak muscles allow the kneecap to move sideways and rub against the thigh bone.

A second common treatable cause is rolling the feet onto the outside (pronation) excessively when walking or running while the front thigh muscles (quadriceps) pull the kneecap outward. Together, these forces cause the kneecap to rub against the end of the thighbone.

What causes the Runner’s knee?

Runner’s knee may be caused by a structural defect or a certain way of walking or running. Other causes may include:

  • A kneecap that is too high in the knee joint

  • Weak thigh muscles

  • Tight hamstrings

  • Tight Achilles tendons

  • Poor foot support

  • Walking or running with the feet rolling in while the thigh muscles pull the kneecap outward

  • Excessive training or overuse

  • Injury

What are the symptoms of a Runner’s knee?

These are the most common symptoms:

  • Pain in and around the kneecap that happens when you are active. Or pain after sitting for a long time with the knees bent. This sometimes causes weakness or feelings of instability.

  • Rubbing, grinding, or clicking sound of the kneecap that you hear when you bend and straighten your knee

  • Kneecap that is tender to the touch

The symptoms of a runner’s knee may look like other conditions and health problems. Always talk with your healthcare provider for a diagnosis.