5 common injuries that cause knee pain while running and how to treat them, according to physical therapists

• Knee pain while running is often due to runner's knee, IT band syndrome, and knee bursitis.
• Most running-related knee injuries are the result of increasing your mileage or pace too quickly.
• If you feel knee pain when running, stop training, apply ice, and take over-the-counter pain medications.

Because running is a repetitive, weight-bearing form of exercise, there is a high risk for injuries, particularly involving the knee. In fact, knee injuries are incredibly common, accounting for up to 50% of all running injuries.

Here are five common injuries that might explain knee pain when running:

1. Runner's knee

Runner's knee, also known as patellofemoral pain syndrome, is the most common cause of knee pain among runners, says Robert Wilder, MD, chair of the Department of Physical Medicine and Rehabilitation at the University of Virginia.

Where it hurts: Pain manifests around the patella (kneecap), either when active or after sitting with your knees bent for a long time.

What causes it: As we run, the kneecap, the femur, and the tibia all move, putting pressure on the kneecap. When too much load is placed on the kneecap, the tissues can become inflamed and irritated, Wilder says. It can also be caused by tight muscles, poor running form, or a structural issue, like an abnormally high knee cap.

How to treat it: Stop running, apply cold packs, and take a pain reliever like ibuprofen until you are pain-free and ready to run again. Strengthening your knees, hips, feet, and ankles can also help treat and prevent runner's knee. Talk with a physical therapist to find the right treatment plan for you. If your pain does not go away after three or four weeks, Wilder says you should see a doctor.

2. Iliotibial (IT) band syndrome

Iliotibial (IT) band syndrome is another common running injury, especially amongst long-distance runners. It affects the iliotibial band - a layer of connective tissue that runs from the hip to just past the knee, says Steven Mayer, MD, a sports medicine physician at Northwestern Medicine Running Clinic.

Where it hurts: Pain is located on the outside of the knee.

What causes it: IT band syndrome is typically caused by overuse and tightness of the iliotibial band. Mayer says runners tend to experience tightness in the IT band because they are frequently moving backward and forwards (as opposed to side to side), which causes friction where the IT band meets the knee, producing inflammation and pain.

How to treat it: Stop running, try foam rolling, and strengthen your core and hips, Mayer says. You can also ice the outside of your knee or take over-the-counter medication for pain. IT band syndrome usually resolves in a few weeks, Mayer says. However, if pain persists see a doctor as IT band syndrome can sometimes become chronic, requiring a month or two of rehabilitation.

3. Patellar tendinitis

Patellar tendinitis, also known as jumper's knee, is another common running injury.

Where it hurts: Patellar tendinitis causes pain below the knee in the patellar tendon which connects the kneecap and shin. This tendon is what allows you to fully extend your knee.

What causes it: Patellar tendinitis is caused by overuse or suddenly increasing running distance or frequency. This places additional stress on the patellar tendon, causing tiny tears that result in pain and inflammation. Having tight quad muscles or hamstrings can also put added strain on the patellar tendon.

How to treat it: Wilder says the best way to treat patellar tendinitis is by taking a break, icing the affected area, and strengthening and stretching your thigh muscles. Flexibility and strengthening exercises can also stimulate tissue healing, Wilder says. It's also helpful to wear a patella brace to reduce the load on the tendon.

4. Meniscus tear

A meniscus tear is an injury in the piece of cartilage that sits between your shinbone and thighbone.

Where it hurts: Each of your knees has two menisci - one on the inside of the knee and one on the outside of the knee. A torn meniscus causes pain and inflammation around the knee which can make it hard to fully extend the joint.

What causes it: Meniscus tears are usually caused by repetitive use of the menisci or by activities that involve twisting, like when you stop suddenly while running or quickly change directions.

How to treat it: Stop running for a short period of time while the injury heals, Mayer says. In milder cases, rest, ice, and medication can help relieve the symptoms so it's safe to run again, even if they don't repair the tear itself. In extreme cases with persistent symptoms, you may need to undergo surgery.

5. Knee bursitis

Knee bursitis is inflammation or irritation of a small fluid-filled sac, called the bursae, located near your knee joint. Mayer says the most common types of knee bursitis in runners are Pes Anserine bursitis, which affects the inside of the knee near the hamstring, or Prepatellar bursitis, which affects the kneecap.

Where it hurts: It causes pain on the kneecap or just below the knee joint towards the inner side.

What causes it: Knee bursitis occurs when one of the bursae in your knee becomes inflamed because of repeated strain, Wilder says. This is usually because a runner decides to increase their mileage or speed suddenly.

How to treat it: Ice, rest, and pain medication are all helpful ways to relieve the pain. Mayer says it is sometimes possible to run through the pain as long as the knee is no longer swollen. Other treatment options for more severe cases include physical therapy, corticosteroid injections, or even surgery to remove the bursa. Sometimes, the bursa can become infected and cause a fever, which usually requires antibiotics to treat. See a doctor determine the right treatment plan for you.

Insider's Takeaway

Knee pain is common in runners, especially if they increase their mileage or pace suddenly. Most common knee injuries can be treated with rest, ice, and over-the-counter pain medication. However, if pain persists for more than a few weeks, reach out to your doctor as you may require more intensive treatment like physical therapy or surgery.

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