Iliotibial Band Syndrome Iliotibial band syndrome (ITBS or ITBFS, for Iliotibial Band Friction Syndrome) is one of the main causes of lateral knee pain in runners but also associated with cycling, hiking and weight lifting, especially squats. The iliotibial band is a superficial thickening of tissue on the outside of the knee, extending from the outside of the pelvis, over the hip and knee, and …