The iliotibial band (i.e. IT band) is a thick band of tissue that runs along the lateral thigh. It crosses the hip and knee joints while helping to control the leg angle leg when running. IT band friction syndrome occurs when there is pain over the outer side of the knee during running. Risk factors include a tight IT band, weak hip muscles or foot over-pronation. With activities such as running, the repetitive rubbing of the iliotibial band over bursae causes pain.
