Final answer:
Iliotibial band syndrome (ITBS) is primarily caused by the friction of the IT Band, especially during repetitive knee movements, and is also associated with weak glute muscles.
Step-by-step explanation:
Iliotibial band syndrome (ITBS) is often caused by friction of the IT Band as it moves over the lateral femoral epicondyle during repeated flexion and extension of the knee. The iliotibial tract muscle, which consists of the gluteus maximus and connective tissue from the tensor fasciae latae, inserts onto the tibia. When there's excessive friction, particularly due to overuse, the area can become inflamed, leading to ITBS. Additionally, weak glute muscles can contribute to the development of ITBS by causing an imbalance in muscle strength and gait that can increase stress on the IT band.