context: If you've got a nagging pain on the outer part of your knee, especially if you're a runner, it could be a symptom of iliotibial band ( IT band) syndrome. It's an injury often caused by activities where you bend your knee repeatedly, like running, cycling, hiking, and walking long distances. Your IT band is a thick bunch of fibers that runs from the outside of your hips to the outside of your thigh and knee down to the top of your shinbone. If your IT band gets too tight, it can lead to swelling and pain around your knee. IT band syndrome usually gets better with time and treatment. You don't typically need surgery. The problem is friction where the IT band crosses over your knee. A fluid-filled sac called a bursa normally helps the IT band glide smoothly over your knee as you bend and straighten your leg. But if your IT band is too tight, bending your knee creates friction. Your IT band and the bursa can both start to swell, which leads to the pain of IT band syndrome. Several things can up your odds of getting it. Some you can help, and others you can't. Not using the right training techniques. Not doing enough to stretch, warm up, and cool down Pushing too hard -- you go too far or for too long Not resting long enough between workouts Wearing worn-out sneakers Running or training on the wrong surfaces. Running downhill Running only on one side of the road. Because roads slope toward the curb, your outside foot is lower, which tilts your hips and throws your body off. Training on banked, rather than flat, surfaces. Most running tracks are slightly banked. Certain physical conditions. Some traits raise your chances of getting IT band syndrome: Bowed legs Knee arthritis One leg that's longer than the other Rotating your foot or ankle inward when you walk or run Rotating your whole leg inward when you walk or run Weakness in your abs, glutes, or hip muscles The main symptom is pain on the outer side of your knee, just above the joint. Early on, the pain might go away after you warm up. Over time though, you may notice it gets worse as you exercise. Other symptoms include: Aching, burning, or tenderness on the outside of your knee Feeling a click, pop, or snap on the outside of your knee Pain up and down your leg Warmth and redness on the outside of your knee See your doctor if you have these symptoms, especially if any existing ones get worse. Typically, your doctor can tell you have IT band syndrome based on your symptoms, health history, and a physical exam. It's not the only cause of outer knee pain, so you may get an X-ray to rule out other causes. If you closely follow your doctor's orders and give yourself the rest you need, you can usually recover from it in about 6 weeks. Some basic steps can help ease the pain and swelling: Don't do activities that trigger the pain. Take over-the-counter pain relievers. Wrap an ice pack in a towel and put it on the outside of your knee for 10-15 minutes at a time. A physical therapist can: Give you tips for how to best warm up and cool down Help you choose footwear and, if you need them, shoe inserts Show you exercises to help strengthen and stretch your IT band and leg muscles Talk to you about how to adjust your training schedule Teach you how to improve your form to go easier on your body Use friction massage, ice, or ultrasound to help with pain and swelling That usually does the trick, though some people need cortisone injections to help with pain and swelling. To help prevent IT band syndrome, you can: Allow plenty of time to properly stretch, warm up, and cool down. Give your body enough time to recover between workouts or events. Run with a shorter stride. Run on flat surfaces or alternate which side of the road you run on. Replace your shoes regularly. Stretch your IT band, hip muscles, thigh muscles, and hamstrings often. Use a foam roller to loosen up your IT band.