The IT Band (a.k.a. iliotibial tract band) is a thick piece of fascia , or connective tissue, that runs from the side of the hip down to the side of the knee, says Bianca Spicer, exercise physiologist and owner of Spicer Fitness and Wellness in Atlanta, Georgia. You can think of it kind of like a rubber band, as it functions inside your body in a similar way.

Whenever your leg moves backwards, like during a stride, elastic energy is stored and then released as your leg swings forward again. The IT band ultimately helps your body save energy, especially during a run, according to research from scientists at Harvard University.

Given its important role in keeping your upright and moving, having healthy IT bands is super important. So is knowing when you're just stiff from, say, a hardcore sprint workout , and need to do some extra stretching or time to recoveror when you're actually hurt and need to give it time to heal.

Signs And Symptoms Of An IT Band Injury

As useful as the IT band is, its also easy to get it injured. That technical term for this is IT band syndrome, and it's the second most common running injury , according to research from the Physical Medicine and Rehabilitation Clinics of North America . Symptoms of IT band syndrome include:

  • Pain on the outside of your knee
  • Swelling
  • Pain when bending your knee

Common Causes Of IT Band Syndrome

Your glute muscles, hips, and hamstrings all run along your IT bands and work in tandem with it to help stabilize your knee. Because of this, after intense lower-body workouts, runs, jump training (a.k.a. plyometrics), or even a lot of brisk walking, the IT band may become inflamed.

In general, there are three usual suspects that cause IT band injuries:

What To Do If You Think You Have An IT Band Injury

If youre not sure whether your pain is IT band syndrome, Spicer recommends getting a formal diagnosis from a physical therapist. For mild pain, changes like better form, more rest, and rehab exercises (e.g. strengthening your hips, butt muscles, and outside of your thighs) should help.

One treatment Spicer doesnt recommend? Using the Instagram-famous foam rollers on your IT band. You want to make sure youre foam rolling the muscle, she says. The biggest mistake we see with adjusting the IT band is people mistaking the IT band for [muscle] and foam rolling the wrong thing. So stick to hitting your quads, hammies, glutes, and inner thighs and give your IT band a break.