Download Understanding the Tensor Fascia Lata

The Tensor Fascia Lata and Unequal Leg Length
© 2006 Lawrence Gold
The tensor fascia lata (TFL) is a muscle continuous with the fascia lata, a
tendon of unusual shape, that of a broad sheath that runs along the lateral aspect
of the thigh and inserts at the lateral epicondyle of the tibia.
Its function is distinct from those of neighboring muscles, the gluteus medius,
which abducts and extends the thigh, and gluteus minimus, which flexes and
internally rotates the thigh. Despite analysis based upon its location, the TFL functions
as neither an abductor nor flexor of the thigh at the hip, but elevates the opposite
side of the pelvis by pulling down on its attachment near the ASIS during the footdown phase of walking or running. That is, when ones weight is on one leg and
stabilized by the ground, the tensor fascia lata contracts, 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, contralateral movements of walking, than of training that addresses one leg at a time.
Problems of apparent unequal leg length may 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.
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 is a superior
approach to unequal leg length than massage, stretching, orthotics, icing, or
cortisone injections.