The Iliotibial tract band – IT band – is a long ligament that runs down the outside of your upper leg. This band of tissue connects to the hip via the tensor fascia latae (TFL) and the gluteus maximus and to the knee via the tibialis anterior and the peroneus longus. The IT band helps to stabilize and move the knee joint, and tightness or inflammation of this band can lead to problems like IT band syndrome and knee and hip pain.

A common misconception about the IT band is that you can stretch it. However, because the IT band is a ligament, not a muscle, you need to stretch the muscles connected to it. Stretching a tendon or ligament can lead to injury.