Iliotibial Band Syndrome (ITBS) is an overuse injury of the iliotibial band, a thick fascia that runs down the outside of the thigh. ITBS is caused by training errors like increasing mileage too quickly, running on uneven surfaces, or having poor form. Anatomical factors like tight muscles or leg length differences can also contribute. Diagnosis involves pain tests like the Renne Test or Noble Compression Test. Treatment starts with rest, ice, stretching, and anti-inflammatories. Later stages may include corticosteroid injections, surgery for refractory cases. Prevention focuses on gradual mileage increases, proper footwear, stretching, and avoiding uneven terrain.