Iliotibial band syndrome (ITBS) is a common running injury of the lateral knee, comprising approximately twelve percent of all injuries in runners. ITBS pain is normally experienced on the outer side and just above the knee joint.
What is the Iliotibial band (ITB)?
The ITB is not a muscle, but rather a thick band of connective tissue that runs down the outside of the thigh from the pelvis to the shin bone (tibia). It crosses both the hip and the knee joint, providing lateral stability. Near the hip, the ITB originates from the tensor fascia lata muscle and gluteus maximus muscle. As the ITB is a thick band of fascia, it is not possible to stretch the ITB itself.
What is Iliotibial Band Syndrome (ITBS)?
There is some debate with regard to the exact cause of ITBS. The longstanding theory has been that a tight ITB causes friction over the femoral condyle as the knee bends, which leads to inflammation and pain. Recent research, however, has challenged this view, with the current theory being that a highly innervated layer of fat gets compressed between the ITB and femoral condyle, causing inflammation and pain. However, further research is needed to confirm this theory.
What causes ITBS?
ITBS is classified as an overuse injury, with training error therefore being a significant cause. Increasing training volume (how much), intensity (how hard) and frequency (how often) too fast can lead to the capacity of the tissues being exceeded, resulting in inflammation and pain. Further contributing factors are poor movement control and gluteal weakness. Dynamic knee valgus, where the knee rolls in during an activity, will result in the insertion of the ITB moving away from the origin, causing more compression and load on the ITB at the knee joint.
How to treat ITBS?
ITBS has long been treated with stretching of the ITB and using foam rolling and deep tissue massage to loosen the tight ITB. However, the ITB is a non-contractile tissue, and has been shown to have the tensile strength of steel. The tension of the ITB, however, can be increased by the muscles that insert into it at the hip, being the tensor fascia lata and gluteus maximus. If these muscles cannot handle the load that is being exerted on them, they can tighten up as a result. Treatment of ITBS should initially focus on settling the symptoms, by resting (relatively) from the aggravating activity. Once symptoms have settled, exercises should be introduced to address muscle weakness and correct movement control.