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Posts tagged “anatomy

The Illiotibial Band: Nefarious Foe, or Misunderstood Friend?

Runners, cyclists, and just about anyone who moves their legs on a regular (or irregular) basis has probably encountered the Iliotibial Band: a dense, fibrous tract of tissue running from the outside of the hip along the side of the thigh to connect just below the knee. And if you have experienced sensation associated with this tissue structure, chances are high that it was not a good experience.

afp20050415p1545-f1IT Band pain symptoms and range of motion inhibition, often referred to under the umbrella term “IT Band Syndrome,” is a common condition among individuals who engage in repetitive leg flexion and extension, and while exact figures for the entire population are unknown, some studies estimate prevalence over 20% in people who run or walk long distances. Symptoms usually present with pain in the lateral hip or the attachment at the knee, although sometimes tissue adhesions in the side of the leg cause pain when the structure is stretched, as in running or cutting movements.

The IT Band is itself not a muscle — structurally, it can be thought of as a long tendon tail attaching at the bony prominence at the top of the lower leg, just below the knee (at the prominent knob of the lateral head of the Tibia bone; it probably hurts a bit if you press on it), running up the side of the thigh, and fanning out to blend into the Tensor Fascia Latae hip muscles and Gluteus Maximus, which finally attach at the Iliac Crest, the upper rim of the pelvis (hence ilio-tibial). Like all tendons, the IT Band has little blood supply and nerve innervation, and is primarily composed of collagen, elastin, and fibroblast cells. While it cannot contract on its own, the muscles at the top of the hip (primarily the Tensor Fascia Latae) put tension on the IT band to abduct (bring away from the body’s center line) the hip and leg. Think of a rope and pulley system — the rope in this case represents the passive IT Band structure, serving to distribute the force applied to it from the other side of the pulley. This is particularly important in walking and running, where the leg involved in stepping forward during the “swing” phase of gait relies on the abductors and deep lateral rotator muscles of the hip to keep the pelvis level and stable. You may have seen runners or walkers whose hips “dip” with every step — this often indicates dysfunction in the Tensor Fascia Latae and hip rotators.

It is important to view the above graphic as a representation of the actual structure within the body; I like how the artist has indicated that the white tendinous fibers of the IT Band blend into the muscle tissue at the hip, but I think the characterization of the IT Band as a separate bundle of tissue laying on top of the surrounding muscle is a common misunderstanding, and refining our concept of the IT Band as it actually exists and functions in the body has great implications for practitioners and athletes alike.

the_muscles_of_the_leg_919014Our understanding of human anatomy comes largely from dissection of cadavers, wherein individual muscles and anatomical structures are identified by being excised with a scalpel from the surrounding tissue. This gives us a detailed sense of the three-dimensional body, but by manually separating the tissue, we also often tend to mentally isolate these structures and forget that the elegant, intricate musculoskeletal system recruits fibers from a broad range of tissues for almost every motion. Take a look at Leonardo da Vinci’s drawing of a dissected leg to the right (click to expand to full size). This intricate and amazingly accurate drawing from the early days of human anatomical study indicates the same fanning connective tissue structure in the upper hip as it blends with the hip abductor muscles, but we don’t see the same IT band structure drawn separately from the surrounding tissue — it’s more of a thickened strip of tissue that forms a groove in the side of the thigh. You may have seen athletes with highly defined, sculpted musculature who exhibit the same structure; the IT Band appears as a groove along the side of the thigh and forms a tendon bundle at the tibia attachment. Just as the connective tissue structure of the IT Band blends into muscle at the hip attachment, there is also a great deal of “feathering” into the muscles of the lateral thigh — namely, the lateral quadriceps and hamstrings.

DSC_0151Why is this distinction important? To go back to the previous rope and pulley analogy, we can refine this understanding to not just a single rope pulling on a single endpoint in a single plane of movement, but a network of pulleys pulling on a web of ropes that disperses tension across a wide area, with each structure interacting as tension is applied and released. The interactions are so intricate that even the most sophisticated biomechanics models can only provide simplified schematics of the forces at work in the living body. You may have seen similar art and architectural structures, called “tensegrity models” that exemplify this concept. Below is a video of renowned bodywork practitioner, researcher, and teacher Tom Myers showing an example of a tensegrity structure and how it relates to the body:

Watch how the model moves when Tom pulls on a piece of the elastic thread — look closely and you will be able to see other elastic threads disperse tension, with some going taut and others going slack, which changes the position of the rigid dowels. The model demonstrates how a rigid structure with limited elasticity can affect the contractile structures it attaches to. An example of this in practice might be flexion of the hip to kick a soccer ball. As the leg is brought up and the angle of the hip becomes more acute, the quadriceps fire to extend the knee and flex the hip. Since these fibers tie into the IT band, this motion exerts force along the length of the IT band, which will functionally rotate the leg inward (medially). To prevent rotation, the deep lateral rotators that run across the glutes must fire to compensate. This is a simplified explanation of the processes at work, but is meant to demonstrate the kinetic chain of events that occurs with movement and the forces at work to stabilize and compensate to promote strength, accuracy, and protect against injury.

Taking this same example a step further, suppose one of the muscles working in concert to accomplish the kicking action is weak or impaired due to injury or improper training. The Piriformis, one of the deep lateral rotators of the hip that runs beneath the glutes from the Sacrum to the Femur, is a common offender for hip instability and insufficiency. Without the Piriformis firing properly to prevent medial rotation, other muscles that may not be as well adapted for hip rotation must be recruited to preserve stability, including the Tensor Fascia Latae. The IT Band, already under tension from its connection with the Quadriceps, comes under additional tension from the Tensor Fascia Latae to pull the leg into alignment, putting even greater stress on the IT Band attachment at the knee. Can you see how this could lay the groundwork for pain, inflammation, and chronic injury?

The prescribed treatment for pain and tightness in the IT Band has long been stretching, manual therapy, and foam rolling along the length of the outside of the leg, which still assumes the concept of the IT Band as its own discrete, free-gliding bundle of tissue and discounting the connectivity to the surrounding muscle. I’m making the argument that this isn’t necessarily the most effective nor the best biomechanically sound approach to treating IT Band Syndrome symptoms. Stick with me here.

Think again back to the tensegrity model Tom Myers was playing with. If one segment of the elastic thread was under significant tension, it would produce slack on other thread segments — that’s how vector energy dispersal works. What if, instead of approaching the problem by addressing the tight thread, we look for ways to bring appropriate tension into the slack threads? This accomplishes the same goal of dispersing tension equally, without further assaulting already inflamed, sensitive tissue.

In the case of the IT Band, this translates to gentle stretching and mobilization of the Tensor Fascia Latae — remember, the IT Band itself is essentially a passive structure and translates tension from other muscle attachments instead of exerting any force itself — and rehabilitative exercise to strengthen the deep lateral rotators in the hip and glutes. I am not recommending this as a cure-all approach for every presentation of hip and lateral knee pain; always seek evaluation from a medical practitioner to properly diagnose pathology and pursue the best course of treatment. For everyday tight, tender IT Bands, here are three exercises that target the supporting musculature to promote balance and optimal movement patterns:

First, the Clamshell — the model in the video is using a resistance band, which can be omitted and introduced later as strength and mobility progress.

Next, the Glute Bridge; I like this single-leg variation because it requires more global hip engagement than a symmetrical bridge hip raise. Adjusting the angle of the raised leg (pointing more toward the ceiling) will help to recruit more low back, hip flexors, and hamstrings to maintain balance.

Finally the Triplanar Hip Exercise (one of my clients fondly refers to this as the “fire hydrant;” if you are a dog owner, you will quickly recognize why!). The model in the video has good form but I would recommend slowing down the pace for more accurate muscle recruitment. The three elements are full extension of the leg, lateral rotation, and flexion pulling the knee into the torso.

These exercises are a great starting place to promote hip mobility and strength for runners, cyclists, swimmers, and active individuals in general. You can make them more difficult by taking away the stable base of the solid floor, for which Bosu Balls and wobble boards are excellent tools. These also make a great pre-activity warm-up or post-activity mobilization. If you have sciatica or back pain symptoms, consult a health professional before beginning these exercises, as excessive tension in the deep lateral rotator muscles can sometimes exacerbate nerve impingement symptoms. Always stop if you feel pain or pinching, and work within your abilities, progressing as your strength improves.

I hope this perspective on the IT Band sheds some light on its function and structures. This essential tissue mass in the leg is an important factor in all activity and movement, and healthy function will improve performance and prevent injury.