Final answer:
Pain from ITB syndrome typically occurs as the knee flexes to approximately 30 degrees over the lateral condyle, often due to the iliotibial band irritating the lateral femoral epicondyle.
Step-by-step explanation:
With an ITB syndrome, pain occurs with the knee flexing to approximately 30 degrees over the lateral condyle. This pain is typically due to the irritation of the iliotibial band on the lateral femoral epicondyle during flexion and extension movements. The discomfort is often felt while the knee is in motion, especially when it reaches a semi-flexed position because the iliotibial band shifts over the lateral condyle, causing friction. It is important to note that this is a repetitive motion injury predominantly observed in runners and cyclists. Understanding the mechanics of knee movements and the role of supporting structures such as ligaments and menisci is critical for diagnosing and managing knee injuries effectively.