IT BAND SYNDROME
Knee pain is a common complaint in runners. The key to diagnosis lies in the location of the pain. If you have not had a fall or other type of trauma, then pain over the lateral (outside) knee is very commonly caused by iliotibial band syndrome.
The iliotibial (or IT) band is dense connective tissue that runs along the outside of the leg from the hip down to the knee. As it attaches to the tibia (the shin bone) it has to cross over a bony prominence. The IT band can get irritated at this crossing, and this is made worse with repetitive bending and straightening of the knee.
Runners with IT band syndrome frequently complain of more pain with running downhill as opposed to uphill or on flat surfaces. Pain may be worst when your foot strikes the ground. You may also have pain going up or down stairs. Some runners may also feel or hear a pop as they bend the knee.
Risk factors for developing IT band syndrome include high mileage, worn shoes and running on banked surfaces or always running in the same direction around a track. Over pronation of the feet has also been noted in runners with IT band syndrome. An overworked or tight tensor fascia lata (the muscle attachment of the IT Band at the hip) can predisposed to IT Band Syndrome; so can weakness of the gluteal muscles that work to pull the leg out to the side (hip abductors).
Generally rest, changing running surfaces, and stretching of the IT band are helpful in reducing symptoms. Some runners also find it useful to use a foam roller on the affected side for self-massage (warning: this is typically painful). Ice or ice massage after a run can help to decrease pain and inflammation. If you run on a track, be sure to run both clockwise and counter-clockwise. Cross training can be beneficial during the rest period, but be aware that for some people cycling can also irritate the IT band. Swimming and deep water jogging may be better choices.
If your symptoms are not improving with rest, or if you have a sense of locking or catching of the knee or a feeling that you cannot trust your knee to support you, then see your regular doctor or a sports medicine specialist for an evaluation. These symptoms may indicate a different problem in the knee and may require further investigation.