Fact: forty-two percent of all injuries from overuse affect the knee joint, and runner's knee (a.k.a. patellofemoral pain syndrome or PFPS), is the most common injury among runners.

PFPS can effect both knees, though more commonly it is more painful in one knee. According to the British Journal of Sports Medicine PFPS hinders more young and active people, and twice as many women as men. This is most likely because women tend to have wider hips, resulting in a greater angling of the thighbone to the knee, which puts the knee cap under more stress. The symptoms of PFPS are caused by the irregular tracking of the patella (kneecap) in the femoral groove.

What are the common symptoms of PFPS?

The most common complaint of those suffering with PFPS is tenderness behind and around the knee. Some also experience pain on the posterior side of the knee capsule as well. Instability and cracking could also be signs of PFPS. Although symptoms will be different in each case, running on hills and uneven surfaces often aggravates PFPS symptoms.

What are possible causes of PFPS?

Determining a single cause of your knee pain can be quite difficult. A good approach to eliminating your pain is having your knee assessed by a physical therapist. Anterior knee pain could be a biomechanical problem. Biomechanical issues that may be causing your pain include: excessive internal rotation of your hip, your knee cap may sit too high or too low in its groove, worn cartilage in the knee joint which reduces shock absorption, high arches of the feet providing less cushioning and flat feet, or knees that turn in or out excessively can pull the patella sideways. There could also be muscular issues contributing to your PFPS. Tight hamstrings and calf muscles, in particular, can put excessive pressures on the knee. Weak quadriceps muscles can also cause the patella to track out of alignment, creating painful friction and rubbing.

What can I do to help with PFPS?

A good physical therapist can perform a thorough assessment and determine what factors could be contributing to your knee pain. They would also evaluate your running stride while running on a treadmill to determine if there are any problems with your running technique and gait which may be the culprit of your pain. Treatment will likely consist of exercises to focus on correcting existing muscle imbalances and improving strength in weak muscles. You will also perform a flexibility program for the hamstrings, calves and hip flexors, and education on proper footwear and referral for orthotics to correct your foot positioning, if necessary. The rule is if your feet have good form, your knees will follow.

Some smart ways to prevent PFPS is to try running on softer surfaces like grass or trails. Also, don't do too much. Increasing your weekly mileage more than ten percent each week is too much. And lastly, running on hills can be good for your heart but hard on your knees; make sure to introduce a hill routine slowly! For the best advice contact a good physical therapist who can analyze your running gait and provide strengthening exercises to prevent future pain in your knees.