The Tensor Fascia Lata and Unequal Leg Length

The tensor fascia lata (TFL) is a muscle continuous with the fascia lata (iliotibial tract \ IT band), a tendon of unusual shape, a broad sheath that runs along the outside of the thigh and inserts at the side of the tibia near the knee.

Despite analysis based upon its location, the TFL functions as neither an abductor nor flexor of the thigh at the hip, but lifts the opposite side of the pelvis by pulling down on its attachment near the AIIS (anterior inferior iliac spine) during the foot-grounded period of walking or running. That is, when weight is on one leg and stabilized by the ground, the tensor fascia lata pulls down on its side of the pelvis and elevates the opposite side, as the opposite leg swings forward.

The action of the TFL is aided by the quadratus lumborum (QL) of the opposite side, contraction of which helps elevate that side of the pelvis.

In effect, the TFL and QL together cause a reaching action of the leg. The abdominal obliques of the QL (opposite) side usually participate, as well,

Movements of these muscles are synergistically aided by a movement of the opposite leg knee-forward in hip flexion, as the iliopsoas muscles and gluteus minimus bring the free leg forward.

This synergy is better understood not as "muscles helping each other," but as "the brain coordinating movements," since coordination is a brain function and coordinated leg action is inherent in organisms with legs. For movement education purposes, a higher level of brain-integration results from movement training that involves both legs at the same time, each leg doing its respective, opposite, contra-lateral movements of walking, than of training that addresses one leg at a time.

Problems of apparent unequal leg length often involve a habitually contracted TFL on the longer-leg side and contracted psoas and obliques on the shorter leg side. Hip joint compression due to contracted glutei may also be involved, a problem that often leads to hip joint replacement surgery. Heightened tension of the TFL places strain on the fascia lata, inducing "IT Band Syndrome," which can be relieved by freeing the person with a tight TFL from the reflexive muscular tension holding the TFL and its synergists tight, generally through sensory-motor training (a sub-speciality of somatic education).

Leg retraction (along its length - as would result from action of the same-side QL or obliques) inhibits or interferes with, or otherwise confuses the action of the same-side TFL and must be addressed for movement training to be optimally successful. That means the movements of both leg protraction (reaching) and retraction (pulling short) must be freed and improved, When working with the TFL of one side, a movement of knee toward chest of the other leg is useful.

Unequal leg length generally indicates an injury to one side of the body (not necessarily a lower extremity injury) at some time in life, where the change of leg length came not from the injury, but from the protective cringing at the site of injury, leading to retraction of the extremity. Activity in stressful athletic situations (such as downhill walking or running) may further trigger the retraction response.

With this understanding, it is evident why movement training via somatic education is a superior approach to unequal leg length than massage, stretching, orthotics, icing, or cortisone injections, and how somatic education can complement and accelerate progress in physical therapy.