Anatomical Factors
Certain anatomical factors can significantly increase an individual’s risk of developing Iliotibial Band Syndrome by altering lower limb biomechanics and increasing strain on the IT band. These are structural characteristics that a person is born with or develops over time.
While these factors do not guarantee that someone will get ITBS, they create a predisposition that makes the tissues more vulnerable to overuse, especially when combined with training errors. Key anatomical risk factors include high or low foot arches, a true leg-length discrepancy, and bow-leggedness (genu varum).
For example, high or low foot arches can affect the entire kinetic chain from the foot to the hip. Foot mechanics play a critical role in how forces are transmitted up the leg.
Individuals with high, rigid arches (pes cavus) often have feet that supinate or underpronate, meaning they don’t roll inward enough upon foot strike. This can increase shock transmission up the leg and place more stress on the lateral structures, including the IT band.
Conversely, those with flat feet or low arches (pes planus) tend to overpronate, causing the foot and lower leg to roll inward excessively. This internal rotation of the tibia can increase the angle at the knee and create a wringing effect on the IT band, pulling it tighter against the femur.
Besides, a true anatomical difference in the length of the leg bones can cause an imbalance in the pelvis and alter gait mechanics. The IT band on the longer leg may be subject to increased tension and friction due to the pelvic tilt and compensatory movements made during running or walking.
Specially, bow-leggedness (Genu Varum), where the knees angle outward, naturally increases the angle between the femur and the tibia on the outside of the knee. This greater angle can cause the IT band to be stretched more tightly across the lateral femoral epicondyle, increasing the compressive and frictional forces in this area with every step and predisposing the individual to irritation and inflammation.
Muscle Imbalances
Muscle imbalances, particularly weakness in the hip abductor muscles and poor core stability, are a primary contributor to the development of ITBS because they lead to faulty movement patterns that overload the iliotibial band.
When key stabilizing muscles are not doing their job correctly, other structures are forced to compensate, and the Iliotibial Band Syndrome often bears the brunt of this dysfunction. The most commonly implicated muscles are the gluteus medius, the other external rotators of the hip, and the deep core muscles that stabilize the pelvis and trunk.
More specifically, weak gluteus medius and hip abductors creates a cascade of biomechanical failures. The gluteus medius is the primary muscle responsible for stabilizing the pelvis when you are on one leg, as is the case during every step of running. When this muscle is weak, it cannot prevent the opposite side of the pelvis from dropping, a gait deviation known as a Trendelenburg sign.
To compensate for this pelvic instability, the tensor fasciae latae (TFL), a smaller muscle that attaches directly to the IT band, becomes overactive and tight. This overactivity increases tension along the entire IT band, pulling it taut and causing it to rub more forcefully against the outside of the knee.
In addition, weak core can cause this syndrome. The core muscles, including the abdominals, obliques, and lower back muscles, work to keep the torso and pelvis stable during dynamic movements.
A weak core allows for excessive trunk rotation and side-to-side motion while running. This instability forces the hip muscles to work harder to control the lower body, leading to fatigue and further contributing to poor running form.
The result is often increased adduction (inward movement) of the thigh and internal rotation of the femur, which places greater strain and compressive force on the IT band. Essentially, a lack of proximal stability at the core leads directly to distal problems at the knee.
