IT band syndrome: outer knee pain in runners

What IT band syndrome is

The iliotibial band (IT band) is a thick strip of connective tissue running down the outside of the thigh from the hip to just below the knee. It is not a muscle and cannot be stretched much; it acts more like a strong strap that helps stabilise the hip and knee.

IT band syndrome was once thought to be caused by the band rubbing back and forth over the bone at the outside of the knee. The current understanding is that the band compresses sensitive fatty and connective tissue underneath it, particularly when the knee is bent around 30 degrees, which is the angle your knee passes through as your foot hits the ground in running. Repeat that thousands of times with more load than the tissue is ready for, and it becomes irritated.

Common causes and who gets it

It is one of the most common running injuries and is also seen in cyclists, hikers and rowers. It usually follows a change in load rather than appearing out of nowhere.

• A quick increase in weekly mileage, or adding long runs too fast
• Lots of downhill running, or running on a cambered road always in the same direction
• A sudden increase in cycling, especially with a poorly set-up saddle height
• Low strength and endurance in the hip muscles
• A long hike with lots of descent, carrying a heavy pack

Training for a first half-marathon or a HYROX race, where weekly running volume often jumps quickly, is a common story.

Typical symptoms

The classic sign is sharp or burning pain on the outside of the knee that starts at a fairly predictable point in a run, for example after 3 or 4 km, and gets worse if you carry on, sometimes forcing you to stop or walk. Once you stop, it often settles quickly, but going down stairs or walking downhill afterwards can still hurt.

There is usually tenderness on the outside of the knee, just above the joint line. Swelling inside the knee, locking or giving way are not typical and suggest a different problem, such as a meniscus or ligament injury.

What a physio assessment looks at

Your physio will ask about your training history in detail, including recent changes in distance, terrain, shoes and pace. They will examine the knee to rule out a lateral meniscus or ligament problem, test hip strength and control, and may watch you run or do single-leg squats and hops.

Scans are rarely needed. The diagnosis is usually clear from the story and examination, and the most important information is often in your training log.

A physio will also look at the rest of your week. Hard strength sessions on the legs the day before a long run, poor sleep and a crowded schedule all reduce how much running load the knee can handle, and small changes to the order of sessions can make a surprising difference.

What usually helps

The first step is reducing the running or cycling load to a level the knee tolerates, not necessarily stopping completely. That might mean shorter runs that finish before the pain starts, flatter routes, avoiding downhill sections for a while, or swapping some runs for cross-training that does not provoke it. A small increase in step rate, around 5 to 10 percent, reduces the load on the knee for some runners.

Strengthening the hip muscles, particularly the side and back of the hip, helps the leg control load better. Exercises such as the side plank, side-lying leg raises, single-leg bridges and step-downs are common choices. Our guide to foam rolling explains why rolling the IT band may give brief relief but cannot lengthen it, so treat it as optional rather than the treatment.

What you can start with at home

1. Side-lying hip abduction, 3 sets of 12 to 15 each side, slow on the way down.
2. Side plank from the knees, then from the feet, 3 holds of 20 to 40 seconds each side.
3. Single-leg glute bridges, 3 sets of 8 to 12 each side.
4. Step-downs from a low step, keeping the pelvis level and knee in line, 3 sets of 8 to 10.
5. Run only up to the point just before pain normally starts, then stop, and build distance gradually over the weeks.

Our guide to returning to running after injury has a structured progression, and our guide to strength training for runners shows how to keep hips and legs resilient long term.

Cyclists should check their bike fit, particularly saddle height and cleat position, since small changes can reduce the load on the outside of the knee. If you ride and run, it is worth reducing whichever one aggravates it most first, rather than cutting both.

Recovery time and when to get help

Many people improve within 4 to 8 weeks when they adjust their training and build hip strength, although stubborn cases can take a few months. If it keeps coming back at the same point in your runs, a structured plan helps. The on-site physio at Lycan Strength can assess your running and training load, with 20% off for members; book a physio appointment online.

• Go to A&E if you cannot bear weight after an injury, or the knee swelled rapidly after a twist.
• Go to A&E if the knee is hot, red, very swollen and painful, especially with a fever.
• See a GP or physio promptly if the knee locks, gives way or keeps swelling.
• See a GP if you have numbness or tingling down the outside of the leg or foot.

Questions