The iliotibial band (IT band) is a thick band of connective tissue that runs along the outer thigh, extending from the hip to the knee. It plays a crucial role in stabilizing the knee during activities like walking, running, and cycling. The IT band helps maintain proper alignment of the knee joint and supports movements of the leg. Injuries to the iliotibial band, such as iliotibial band syndrome, can occur due to overuse or repetitive activities, often affecting runners and cyclists. Symptoms may include pain on the outer side of the knee. Stretching and strengthening exercises can help alleviate discomfort and prevent further issues.