The TFL: a Pesky Little Muscle

The TFL, or tensor fascia latae is a troublesome little muscle. It sits on the top and front portion of the pelvis. It attaches to the deep fascia of the leg. Fascia is a thin layer of connective tissue that encapsulates muscles like shrink wrap. It also attaches to the IT band (iliotibial band), along with the gluteus maximus. The IT band runs down the lateral part of the leg and inserts below the knee. The IT band is a dense fibrous connective tissue that feels like leather, and is tethered to the femur by a septum. It does not contract, so contrary to popular belief, it does not get tight. However, because of the TFL’s attachment to it, it can pull the leg outward into abduction and/or in front into flexion. Because of its functions, it can easily substitute for other muscles. Herein lies the problem.

The neighbors to the muscle are the high glutes (medius/minimus) and the hip flexors (psoas major/minor, rectus femoris, and iliacus) and the hip external rotators (there are lots of them). If any of these muscles are weak, the TFL kicks in and becomes overactive. Overactivity leads to trigger points and muscular stiffness. Not only that, it changes motor firing patterns. What does that mean? Human movement is complex with lots of parts moving in a sequence like an orchestra. When the sequence is altered, it can lead to dysfunction and injury. For example, it is common to be weak in the hip flexors. The hip flexors play a role in keeping the femoral head (top of your leg) centered in the socket. Remember how the TFL inserts on the IT band? Well the IT band is tethered to your femur by a septum. With an overactive TFL and a weak hip flexor, you have a situation where the hip flexor is not doing its job keeping the head of the femur centered in the socket and the TFL/IT band complex is now pulling your leg forward during hip flexion. This is what we mean by having altered motor firing patterns. This situation can lead to other problems such as instability and possibly labral tearing. 

Another problem that arises with an overactive TFL is that it internally rotates the femur and externally rotates the tibia (shin). One of the most common faults we see in a squat is called “genu valgus”. This means the knee bows inward like “knocked knee” which is what happens with these rotational forces on the leg. There are several causes and while all the actions of the TFL serve a purpose and are not inherently bad, if the muscle is outpowering other muscles then it can contribute to this compensated knee position. To see more on how this knee position can cause damage to the cartilage, read here .

So what can we do about this? You can take care of the trigger points that develop in an overused muscle and help elongate the muscle with a foam roller:

You can use a foam roller to calm the area down. Simply lay on a foam roller and SLOWLY move back and forth on the painful area. Do not roll over the bony area of your hip. Aim for about 2-3 minutes a day or until you feel a change.

You can improve the strength of hip flexors while minimizing the activation of the TFL like this: 

The TFL is an internal rotator of the femur, so by externally rotating, you are turning off the TFL.